Network Working Group Tom Worster (Editor)
INTERNET DRAFT GDC
Expires Aug 1999 Feb 1999
General Switch Management Protocol
<draft-worster-gsmp-00.txt>
Status of this Memo
This document is an Internet-Draft and is in full conformance
with all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering
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"work in progress."
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Acknowledgement
GSMP was created by P. Newman, W. Edwards, R. Hinden, E. Hoffman,
F. Ching Liaw, T. Lyon, and G. Minshall (see [6] and [7]). This
version of GSMP is based on their work.
Abstract
This memo provides the first draft of the specification of a
proposed GSMP standard. It is based on GSMP V2 [7].
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Changes from the pervious draft
Relative to GSMP V2 [7], the changes are as follows:
- The protocol specification has been generalised from ATM
switches to label switches. The VPI/VCI fields in GSMP
messages have been generalised to Label fields. Currently
label formats and semantics and label specific procedures
are defined only for ATM ports.
- Label stacking is supported by the inclusion of up to two
Input Labels or two Output Labels in the connection
management messages.
- A placeholder has been crated for an IP encapsulation of
GSMP messages.
- The security considerations text has been deleted. Security
considerations will be updated in the future based on the
IP encapsulation work.
- Three QoS Models have been introduced: the Service Model,
the Simple Abstract Model and the QoS Profile Model.
- The Service Model has not be introduced to this draft yet.
Placeholders for Service Model definitions have been
created.
- A QoS Model Selector field has been added to the connection
management messages that distinguishes the three QoS
Models. A Service Selector Field repaces the Class of
Service field.
- The delay priorities of GSMP V1.1 [6] and V2 have been
retained in Simple Abstract Model.
- The QoS profiles of V2 have been retained in the QoS
Profile Model.
- Chapter 9, "QoS Messages" and its abstract model have been
deleted and replaced with a placeholder for Service Model
definitions.
- Space has been allocated at the end of Add Branch and Move
Branch Messages to accomodate traffic parameters in the
Service Model.
- The congestion indication flag has been removed.
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- Changed "Port Type" in V2 Port Config Messages to "Line
Type" and reused the name "PortType" to mean "ATM", "FR"
etc.
- Port and All Ports Configuration messages have been
generalised to allow port type specific port configuration
data. Space has been created in these messages for the
Service Model Data.
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Table of Contents
1. Introduction ..................................................... 5
2. GSMP Packet Encapsulation ........................................ 7
2.1 ATM Encapsulation ............................................ 7
2.2 Ethernet Encapsulation ....................................... 8
2.3 IP Encapsulation ............................................ 10
3. Common Definitions and Procedures ............................... 10
3.1 GSMP Packet Format .......................................... 11
3.2 Failure Response Messages ................................... 13
4. Connection Management Messages .................................. 18
4.1 General Message Definitions ................................. 18
4.2 Add Branch Message .......................................... 24
4.3 Delete Tree Message ......................................... 27
4.4 Verify Tree Message ......................................... 27
4.5 Delete All Message .......................................... 27
4.6 Delete Branches Message ..................................... 28
4.7 Move Branch Message ......................................... 30
5. Port Management Messages ........................................ 33
5.1 Port Management Message ..................................... 33
5.2 Label Range Message ......................................... 38
6. State and Statistics Messages ................................... 42
6.1 Connection Activity Message ................................. 42
6.2 Statistics Messages ......................................... 45
6.2.1 Port Statistics Message ............................... 48
6.2.2 Connection Statistics Message ......................... 48
6.2.3 QoS Class Statistics Message .......................... 48
6.3 Report Connection State Message ............................. 48
7. Configuration Messages .......................................... 54
7.1 Switch Configuration Message ................................ 54
7.2 Port Configuration Message .................................. 56
7.2.1 PortType Specific Data ................................ 57
7.3 All Ports Configuration Message ............................. 63
8. Event Messages .................................................. 64
8.1 Port Up Message ............................................. 66
8.2 Port Down Message ........................................... 66
8.3 Invalid Label Message ....................................... 66
8.4 New Port Message ............................................ 66
8.5 Dead Port Message ........................................... 67
9. Service Model Definition ........................................ 67
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10. Adjacency Protocol ............................................. 67
10.1 Packet Format .............................................. 67
10.2 Procedure .................................................. 70
10.3 Loss of Synchronization .................................... 73
11. Summary of Failure Response Codes .............................. 74
12. Summary of Message Set ......................................... 76
13. Security Considerations ........................................ 77
1. Introduction
The General Switch Management Protocol (GSMP), is a general
purpose protocol to control a label switch. GSMP allows a
controller to establish and release connections across the switch;
add and delete leaves on a multicast connection; manage switch
ports; request configuration information; and request statistics.
It also allows the switch to inform the controller of asynchronous
events such as a link going down. The GSMP protocol is asymmetric,
the controller being the master and the switch being the slave.
Multiple switches may be controlled by a single controller using
multiple instantiations of the protocol over separate control
connections.
GSMP may be transported in three ways:
- GSMP may run across an ATM link connecting the controller
to the switch, on a control connection (virtual channel)
established at initialization.
- GSMP operation across an Ethernet link is specified.
- GSMP operation across an IP network is specified.
A label switch is a frame or cell switch that supports connection
oriented switching using the exact match forwarding algorithm
based on labels attached to incomming cells or frames. A switch is
assumed to contain multiple "ports". Each port is a combination of
one "input port" and one "output port". Some GSMP requests refer
to the port as a whole whereas other requests are specific to the
input port or the output port. Cells or labeled frames arrive at
the switch from an external communication link on incoming labeled
channels at an input port. Cells or or labeled frames depart from
the switch to an external communication link on labeled channels
from an output port.
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A switch may support multiple label types, however, each switch
port can support only one label type. The label type supported by
a given port is indicated by the switch to the controller in a
port configuration message. Connections may be established between
ports supporting different label types. Label types include ATM,
Frame Relay and MPLS.
A connection across a switch is formed by connecting an incoming
labeled channel to one or more outgoing labeled channels.
Connections are referenced by the input port on which they arrive
and the Labels values of their incoming labeled channel.
GSMP supports point-to-point and point-to-multipoint connections.
A multipoint-to-point connection is specified by establishing
multiple point-to-point connections each of them specifying the
same output branch. A multipoint-to-multipoint connection is
specified by establishing multiple point-to-multipoint trees each
of them specifying the same output branches.
In general a connection is established with a certain quality of
service (QoS). This version of GSMP supports three QoS Models: a
Service Model, a Simple Abstract Model and a QoS Profile Model.
The Service Model is based on service definitions found external
to GSMP such as in Integrated Services or ATM Service Categories.
Each connection is assigned a specific service which defines the
handling of the connection by the switch. Additionally, traffic
parameters and traffic controls may be assigned to the connection
depending on the assigned service.
In the Simple Abstract Model a connection is assigned a priority
when it is established. It may be assumed that for connections
that share the same output port, an cell or frame on a connection
with a higher priority is much more likely to exit the switch
before a cell or frame on a connection with a lower priority if
they are both in the switch at the same time. The number of
priorities that each port of the switch supports may be obtained
from the port configuration message.
The QoS Profile Model provides a simple mechanism that allows
connection to be assigned QoS semantics defined external to GSMP.
GSMP contains an adjacency protocol. The adjacency protocol is
used to synchronize state across the link, to negotiate which
version of the GSMP protocol to use, to discover the identity of
the entity at the other end of a link, and to detect when it
changes.
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2. GSMP Packet Encapsulation
2.1 ATM Encapsulation
GSMP packets are variable length and for an ATM data link layer
they are encapsulated directly in an AAL-5 CPCS-PDU [3] with an
LLC/SNAP header as illustrated:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LLC (0xAA-AA-03) | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| SNAP (0x00-00-00-88-0C) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ GSMP Message ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Pad (0 - 47 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ AAL-5 CPCS-PDU Trailer (8 octets) +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
(The convention in the documentation of Internet Protocols [5] is
to express numbers in decimal. Numbers in hexadecimal format are
specified by prefacing them with the characters "0x". Data is
pictured in "big-endian" order. That is, fields are described left
to right, with the most significant octet on the left and the
least significant octet on the right. Whenever a diagram shows a
group of octets, the order of transmission of those octets is the
normal order in which they are read in English. Whenever an octet
represents a numeric quantity the left most bit in the diagram is
the high order or most significant bit. That is, the bit labeled 0
is the most significant bit. Similarly, whenever a multi-octet
field represents a numeric quantity the left most bit of the whole
field is the most significant bit. When a multi-octet quantity is
transmitted, the most significant octet is transmitted first. This
is the same coding convention as is used in the ATM layer [2] and
AAL-5 [3].)
The LLC/SNAP header contains the octets: 0xAA 0xAA 0x03 0x00 0x00
0x00 0x88 0x0C. (0x880C is the assigned Ethertype for GSMP.)
The maximum transmission unit (MTU) of the GSMP Message field is
1492 octets.
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The virtual channel over which a GSMP session is established
between a controller and the switch it is controlling is called
the GSMP control channel. The default VPI and VCI of the GSMP
control channel for LLC/SNAP encapsulated GSMP messages on an ATM
data link layer is:
VPI = 0
VCI = 15.
2.2 Ethernet Encapsulation
GSMP packets may be encapsulated on an Ethernet data link as
illustrated:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Address |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| Source Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Ethertype (0x88-0C) | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
~ GSMP Message ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sender Instance |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Receiver Instance |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Pad |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Frame Check Sequence |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Destination Address
For the SYN message of the adjacency protocol the
Destination Address is the broadcast address
0xFFFFFFFFFFFF. (Alternatively, it is also valid to
configure the node with the unicast 48-bit IEEE MAC
address of the destination. In this case the configured
unicast Destination Address is used in the SYN message.)
For all other messages the Destination Address is the
unicast 48- bit IEEE MAC address of the destination.
This address may be discovered from the Source Address
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field of messages received during synchronization of the
adjacency protocol.
Source Address
For all messages the Source Address is the 48-bit IEEE
MAC address of the sender.
Ethertype The assigned Ethertype for GSMP is 0x880C.
GSMP Message
The maximum transmission unit (MTU) of the GSMP Message
field is 1492 octets.
Sender Instance
The Sender Instance number for the link obtained from
the adjacency protocol. This field is already present in
the adjacency protocol message. It is appended to all
non- adjacency GSMP messages in the Ethernet
encapsulation to offer additional protection against the
introduction of corrupt state.
Receiver Instance
The Receiver Instance number is what the sender believes
is the current instance number for the link, allocated
by the entity at the far end of the link. This field is
already present in the adjacency protocol message. It is
appended to all non-adjacency GSMP messages in the
Ethernet encapsulation to offer additional protection
against the introduction of corrupt state.
Pad
The minimum length of the data field of an Ethernet
packet is 46 octets. If necessary, padding should be
added such that it meets the minimum Ethernet frame
size. This padding should be octets of zero and it is
not considered to be part of the GSMP message.
After the adjacency protocol has achieved synchronization, for
every GSMP message received with an Ethernet encapsulation, the
receiver must check the Source Address from the Ethernet MAC
header, the Sender Instance, and the Receiver Instance. The
incoming GSMP message must be discarded if the Sender Instance and
the Source Address do not match the values of Sender Instance and
Sender Name stored by the "Update Peer Verifier" operation of the
GSMP adjacency protocol. The incoming GSMP message must also be
discarded if it arrives over any port other than the port over
which the adjacency protocol has achieved synchronization. In
addition, the incoming message must also be discarded if the
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Receiver Instance field does not match the current value for the
Sender Instance of the GSMP adjacency protocol.
2.3 IP Encapsulation
3. Common Definitions and Procedures
GSMP is a master-slave protocol. The controller issues request
messages to the switch. Each request message indicates whether a
response is required from the switch and contains a transaction
identifier to enable the response to be associated with the
request. The switch replies with a response message indicating
either a successful result or a failure. There are five classes of
GSMP request-response message: Connection Management, Port
Management, State and Statistics, Configuration, and Quality of
Service. The switch may also generate asynchronous Event messages
to inform the controller of asynchronous events. Event messages
are not acknowledged by the controller. There is also an adjacency
protocol message used to establish synchronization across the link
and maintain a handshake.
For the request-response messages, each message type has a format
for the request message and a format for the success response.
Unless otherwise specified a failure response message is identical
to the request message that caused the failure, with the Code
field indicating the nature of the failure. Event messages have
only a single format defined as they are not acknowledged by the
controller.
Switch ports are described by a 32-bit port number. The switch
assigns port numbers and it may typically choose to structure the
32 bits into subfields that have meaning to the physical structure
of the switch (e.g. slot, port). In general, a port in the same
physical location on the switch will always have the same port
number, even across power cycles. The internal structure of the
port number is opaque to the GSMP protocol. However, for the
purposes of network management such as logging, port naming, and
graphical representation, a switch may declare the physical
location (physical slot and port) of each port. Alternatively,
this information may be obtained by looking up the product
identity in a database.
Each switch port also maintains a port session number assigned by
the switch. A message, with an incorrect port session number must
be rejected. This allows the controller to detect a link failure
and to keep state synchronized.
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Except for the adjacency protocol message, no GSMP messages may be
sent across the link until the adjacency protocol has achieved
synchronization, and all GSMP messages received on a link that
does not currently have state synchronization must be discarded.
3.1 GSMP Packet Format
All GSMP messages, except the adjacency protocol message, have the
following format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Message Type | Result | Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Message Body ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Version
The version number of the GSMP protocol being used in
this session. It should be set by the sender of the
message to the GSMP protocol version negotiated by the
adjacency protocol.
Message Type
The GSMP message type. GSMP messages fall into six
classes: Connection Management, Port Management, State
and Statistics, Configuration, Quality of Service, and
Events. Each class has a number of different message
types. In addition, one Message Type is allocated to the
adjacency protocol.
Result
Field in a Connection Management request message, a Port
Management request message, or a Quality of Service
request message is used to indicate whether a response
is required to the request message if the outcome is
successful. A value of "NoSuccessAck" indicates that the
request message does not expect a response if the
outcome is successful, and a value of "AckAll" indicates
that a response is expected if the outcome is
successful. In both cases a failure response must be
generated if the request fails. For Sate and Statistics,
and Configuration request messages, a value of
"NoSuccessAck" in the request message is ignored and the
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request message is handled as if the field were set to
"AckAll". (This facility was added to reduce the control
traffic in the case where the controller periodically
checks that the state in the switch is correct. If the
controller does not use this capability, all request
messages should be sent with a value of "AckAll.")
In a response message the result field can have three
values: "Success," "More," and "Failure". The "Success"
and "More" results both indicate a success response. The
"More" result indicates that the success response
exceeds the maximum transmission unit of the data link
and that one or more further messages will be sent to
complete the success response. All messages that belong
to the same success response will have the same
Transaction Identifier. The "Success" result indicates a
success response that may be contained in a single
message or the final message of a success response
spanning multiple messages.
The encoding of the result field is:
NoSuccessAck: Result = 1
AckAll: Result = 2
Success: Result = 3
Failure: Result = 4
More: Result = 5.
The Result field is not used in an adjacency protocol
message.
Code
Field gives further information concerning the result in
a response message. It is mostly used to pass an error
code in a failure response but can also be used to give
further information in a success response message or an
event message. In a request message the code field is
not used and is set to zero. In an adjacency protocol
message the Code field is used to determine the function
of the message.
Transaction Identifier
Used to associate a request message with its response
message. For request messages the controller may select
any transaction identifier. For response messages the
transaction identifier is set to the value of the
transaction identifier from the message to which it is a
response. For event messages the transaction identifier
should be set to zero. The Transaction Identifier is not
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used, and the field is not present, in the adjacency
protocol.
The following fields are frequently found in GSMP messages. They
are defined here to avoid repetition.
Port
Gives the port number of the switch port to which the
message applies.
Port Session Number
Each switch port maintains a Port Session Number
assigned by the switch. The port session number of a
port remains unchanged while the port is continuously in
the Available state and the link status is continuously
Up. When a port returns to the Available state after it
has been Unavailable or in any of the Loopback states,
or when the line status returns to the Up state after it
has been Down or in Test, or after a power cycle, a new
Port Session Number must be generated. Port session
numbers should be assigned using some form of random
number.
If the Port Session Number in a request message does not
match the current Port Session Number for the specified
port, a failure response message must be returned with
the Code field indicating, "Invalid port session
number." The current port session number for a port may
be obtained using a Port Configuration or an All Ports
Configuration message.
Any field in a GSMP message that is unused or defined as
"reserved" must be set to zero by the sender and ignored by the
receiver.
It is not an error for a GSMP message to contain additional data
after the end of the Message Body. This is to support development
and experimental purposes. However, the maximum transmission unit
of the GSMP message, as defined by the data link layer
encapsulation, must not be exceeded.
A success response message must not be sent until the requested
operation has been successfully completed.
3.2 Failure Response Messages
[Editor's note: this section has not been updated in this
revision. this section will be updated once more work on new
functions has been added.]
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A failure response message is formed by returning the request
message that caused the failure with the Result field in the
header indicating failure (Result = 4) and the Code field giving
the failure code. The failure code specifies the reason for the
switch being unable to satisfy the request message.
If the switch issues a failure response in reply to a request
message, no change should be made to the state of the switch as a
result of the message causing the failure. (For request messages
that contain multiple requests, such as the Delete Branches
message, the
failure response message will specify which requests were
successful and which failed. The successful requests may result in
changed state.)
If the switch issues a failure response it must choose the most
specific failure code according to the following precedence:
Invalid Message
Failure specific to the particular message type (failure code
16). (The meaning of this failure is dependent upon the
particular message type and is specified in the text
defining the message.)
A failure response specified in the text defining the message
type.
Connection Failures
Virtual Path Connection Failures
Multicast Failures
QoS Failures (QoS failures are specified in Section 9.7.)
General Failures
If multiple failures match in any of the following categories, the
one that is listed first should be returned. The following failure
response messages and failure codes are defined:
Invalid Message
3: The specified request is not implemented on this switch.
The Message Type field specifies a message that is not
implemented on the switch or contains a value that is
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not defined in the version of the protocol running in
this session of GSMP.
5: One or more of the specified ports does not exist.
At least one of the ports specified in the message is
invalid. A port is invalid if it does not exist or if
it has been removed from the switch.
4: Invalid Port Session Number.
The value given in the Port Session Number field does
not match the current Port Session Number for the
specified port.
Connection Failures
8: The specified connection does not exist.
An operation that expects a connection to be specified
cannot locate the specified connection. A connection
is specified by the input port and input label on
which it arrives. An ATM virtual path connection is
specified by the input port and input VPI on which it
arrives.
9: The specified branch does not exist.
An operation that expects a branch of an existing
connection to be specified cannot locate the specified
branch. A branch of a connection is specified by the
connection it belongs to and the output port and
output label on which it departs. A branch of an ATM
virtual path connection is specified by the virtual
path connection it belongs to and the output port and
output VPI on which it departs.
18: One or more of the specified input VPIs is invalid.
19: One or more of the specified Input Labels is invalid.
20: One or more of the specified output VPIs is invalid.
21: One or more of the specified Output Labelss is invalid.
22: Invalid Service Selector field in a Connection Management
message.
The value of the Service Selector field is invalid.
23: Insufficient resources for QoS Profile.
The resources requested by the QoS Profile in the
Service Selector field are not available.
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ATM Virtual Path Connections
24: ATM virtual path switching is not supported on this input
port.
25: Point-to-multipoint ATM virtual path connections are not
supported on either the requested input port or the
requested output port.
One or both of the requested input and output ports is
unable to support point-to-multipoint ATM virtual path
connections.
26: Attempt to add a ATM virtual path connection branch to an
existing virtual channel connection.
It is invalid to mix branches switched as virtual
channel connections with branches switched as ATM
virtual path connections on the same point-to-
multipoint connection.
27: Attempt to add a virtual channel connection branch to an
existing ATM virtual path connection.
It is invalid to mix branches switched as virtual
channel connections with branches switched as ATM
virtual path connections on the same point-to-
multipoint connection.
XX: ATM Virtual path switching is not supported on non-ATM
ports.
One or both of the requested input and output ports is
not an ATM port. ATM virtual path switching is only
supported on ATM ports.
Multicast Failures
10: A branch belonging to the specified point-to-multipoint
connection is already established on the specified
output port and the switch cannot support more than a
single branch of any point-to-multipoint connection on
the same output port.
11: The limit on the maximum number of point-to-multipoint
connections that the switch can support has been
reached.
12: The limit on the maximum number of branches that the
specified point-to-multipoint connection can support
has been reached.
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17: Cannot label each output branch of a point-to-multipoint
tree with a different label.
Some early designs, and some low-cost switch designs,
require all output branches of a multicast connection
to use the same value of Label.
28: Only point-to-point bidirectional connections may be
established.
It is an error to attempt to add an additional output
branch to an existing connection with the
bidirectional flag set.
13: Unable to assign the requested Label value to the
requested branch on the specified point-to-multipoint
connection.
Although the requested Labels are valid, the switch is
unable to support the request using the specified
Label values for some reason not covered by the above
failure responses. This message implies that a valid
value of Lable exists that the switch could support.
For example, some switch designs restrict the number
of distinct Label values available to a point-to-
multipoint connection. (Most switch designs will not
require this message.)
14: General problem related to the manner in which point-to-
multipoint is supported by the switch.
Use this message if none of the more specific
multicast failure messages apply. (Most switch designs
will not require this message.)
General Failures
2: Invalid request message.
There is an error in one of the fields of the message
not covered by a more specific failure message.
6: One or more of the specified ports is down.
A port is down if its Port Status is Unavailable.
Connection Management, Connection State, Port
Management, and Configuration operations are permitted
on a port that is Unavailable. Connection Activity and
Statistics operations are not permitted on a port that
is Unavailable and will generate this failure
response. A Port Management message specifying a Take
Down function on a port already in the Unavailable
state will also generate this failure response.
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15: Out of resources.
The switch has exhausted a resource not covered by a
more specific failure message, for example, running
out of memory.
1: Unspecified reason not covered by other failure codes.
The failure message of last resort.
The following failure response messages are only used by the Label
Range message. [Must come back and revise this --ed]
29: Cannot support requested VPI range.
30: Cannot support requested VCI range on all requested VPIs.
The following failure response messages are only used by the Set
Transmit Cell Rate function of the Port Management
message.
31: The transmit cell rate of this output port cannot be
changed.
32: Requested transmit cell rate out of range for this output
port.
4. Connection Management Messages
4.1 General Message Definitions
Connection management messages are used by the controller to
establish, delete, modify and verify connections across the
switch. The Add Branch, Delete Tree, and Delete All connection
management messages have the following format for both request and
response messages:
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Message Type | Result | Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Port Session Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Input Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|M|B|E|x| |
+-+-+-+-+ Input Label ~
~ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Output Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|QMS|E|x| |
+-+-+-+-+ Output Label ~
~ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number of Branches | Service Selector |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Input PortIdentifies a switch input port.
Flags
M: Multicast
Multicast flag is used as a hint for point-to-
multipoint connections in the Add Branch message. It
is not used in any other connection management
messages and in these messages it should be set to
zero. If set, it indicates that the virtual channel
connection or the virtual path connection is very
likely to be a point-to-multipoint connection. If
zero, it indicates that this connection is very likely
to be a point-to-point connection or is unknown.
The Multicast flag is only used in the Add Branch
message when establishing the first branch of a new
connection. It is not required to be set when
establishing subsequent branches of a point-to-
multipoint connection and on such connections it
should be ignored by the receiver. (On receipt of the
second and subsequent Add Branch messages the receiver
knows that this is a point-to-multipoint connection.)
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If it is known that this is the first branch of a
point-to-multipoint connection this flag should be
set. If it is unknown, or if it is known that the
connection is point-to-point this flag should be zero.
The use of this flag is not mandatory. It may be
ignored by the switch. If unused the flag should be
set to zero. Some switches use a different data
structure for point-to-multipoint connections than for
point-to-point connections. This flag avoids the
switch setting up a point-to-point structure for the
first branch of a point-to-multipoint connection which
must immediately be deleted and reconfigured as point-
to-multipoint when the second branch is established.
QMS: QoS Model Selector
The QoS Model Selector is used to specify a QoS Model
for connection. The value of QMS indicates the value in
the Service Selector should be interprested as a
priority, a QoS profile or a service specification as
shown:
QMS QoS Model Service Selector
--- --------- ----------------
00 Simple Abstract Model Priority
01 QoS Profile Model QoS Profile
10 Service Model Service Specification
11 Reserved N/A
B: Bidirectional
The Bidirectional flag applies only to the Add Branch
message. In all other Connection Management messages it
is not used. It may only be used when establishing a
point- to-point connection. The Bidirectional flag in an
Add Branch message, if set, requests that two
unidirectional virtual channels or virtual paths be
established, one in the forward direction, and one in
the reverse direction. It is equivalent to two Add
Branch messages, one specifying the forward direction,
and one specifying the reverse direction. The forward
direction uses the values of Input Port, Input Label,
Output Port and Output Label as specified in the Add
Branch message. The reverse direction is derived by
exchanging the values specified in the Input Port and
Input Label fields, with those of the Output Port and
Output Label fields respectively. Thus, a connection in
the reverse direction arrives at the input port
specified by the Output Port field, on the label
specified by the Output Label field. It departs from the
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output port specified by the Input Port field, on the
label specified by the Input Label field.
The Bidirectional flag is simply a convenience to
establish two unidirectional connections in opposite
directions between the same two ports, with identical
Labels, using a single Add Branch message. In all future
messages the two unidirectional connections must be
handled separately. There is no bidirectional delete
message. However, a single Delete Branches message with
two Delete Branch Elements, one for the forward
connection and one for the reverse, may be used.
E: Extension Label
The Extension Label flag if zero indicates that the
adjacent Label field is a 28 bit field. If the Extension
Label flag is set then the adjacent Label field is a 60
bit field structured as a 28 bit first level label field
followed by a 32 bit second level label field.
x: Unused
Input Label
Identifies an incomming labeled channel arriving at the
switch input port indicated by the Input Port field. The
value in the Input Label field must be interpreted
according to the Lable Type attribute of the switch
input port indicated by the Input Port field.
Output Port
Identifies a switch output port.
Output Label
Identifies an outgoing labeled channel departing at the
switch output port indicated by the Output Port field.
The value in the Output Label field must be interpreted
according to the Lable Type attribute of the switch
input port indicated by the Output Port field.
Number of Branches
In a success response message and a failure response
message, gives the number of output branches on a
connection after completion of the requested operation.
(A point-to-point connection will have one branch, a
point-to-multipoint connection will have two or more
branches.) If the switch is unable to keep track of the
number of branches on a virtual path connection or a
virtual channel connection it must respond with the
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value 0xFFFF meaning: "number of branches unknown". This
field is not used in the request message.
Service Selector
This field can contain either a QoS Profile Identifier,
a Priority, or a Service Specification. If the QoS Model
Selector is set to 0b00, the Service Selector field
contains a Priority. If the QoS Model Selector is set to
0b01, the Service Selector field contains a QoS Profile.
If the QoS Model Selector is set to 0b10, the Service
Selector field contains a Service Specification. The
Service Selector field is only used in the Add Branch
and Move Branch messages.
A Priority specifies the priority of the connection for
Add Branch and Move Branch messages that choose not to
use a QoS profile, or the QoS capabilities defined in
Section 9, "Quality of Service Messages." The highest
priority is numbered zero and the lowest priority is
numbered "Q-1" where "Q" is the number of priorities
that the output port can support. The ability to offer
different qualities of service to different connections
based upon their priority is assumed to be a property of
the output port of the switch. It is assumed that for
virtual path connections or virtual channel connections
that share the same output port, a cell or frame on a
connection with a higher priority is much more likely to
exit the switch before a cell or frame on a connection
with a lower priority, if they are both in the switch at
the same time. The number of priorities that each output
port can support is given in the Port Configuration
message.
A QoS Profile Identifier is an opaque 16-bit value. It
is used to identify a QoS profile in the switch which
specifies the Quality of Service required by the
connection. QoS profiles are established by a mechanism
external to GSMP.
A Service Specification is an alternative method of
communicating the QoS requirements of a connection. The
Service Specification is defined in Section 9 "Service
Model Definition".
For all connection management messages, except the Delete Branches
message, the success response message is a copy of the request
message returned with the Result field indicating success and the
Number of Branches field indicating the number of branches on the
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connection after completion of the operation. The Code field is
not used in a connection management success response message.
The failure response message is a copy of the request message
returned with a Result field indicating failure and the Number of
Branches field indicating the number of branches on the
connection.
Fundamentally, no distinction is made between point-to-point and
point-to-multipoint connections. By default, the first Add Branch
message for a particular Input Port and Input Label will establish
a point-to-point connection. The second Add Branch message with
the same Input Port and Input Label fields will convert the
connection to a point-to-multipoint connection with two branches.
However, to avoid possible inefficiency with some switch designs,
the Multicast Flag is provided. If the controller knows that a new
connection is point-to-multipoint when establishing the first
branch, it may indicate this in the Multicast Flag. Subsequent Add
Branch messages with the same Input Port and Input Label fields
will add further branches to the point-to-multipoint connection.
Use of the Delete Branch message on a point-to-multipoint
connection with two branches will result in a point-to-point
connection. However, the switch may structure this connection as a
point-to-multipoint connection with a single output branch if it
chooses. (For some switch designs this structure may be more
convenient.) Use of the Delete Branch message on a point-to-point
connection will delete the point-to-point connection. There is no
concept of a connection with zero output branches. All connections
are unidirectional, one input labeled channel to one or more
output labeled channels.
GSMP supports point-to-point and point-to-multipoint connections.
A multipoint-to-point connection is specified by establishing
multiple point-to-point connections each of them specifying the
same output branch. (An output branch is specified by an output
port and output label.)
Label stacking is a technique used in MPLS that allows
hierarchical labeling. MPLS label staching is similar to but
subtley different from the VPI/VCI hierarchy of labels in ATM. ...
[Must add blah --Ed]
The connection management messages may be issued regardless of the
Port Status of the switch port. Connections may be established or
deleted when a switch port is in the Available, Unavailable, or
any of the Loopback states. However, all connection state on an
input port will be deleted when the port returns to the Available
state from any other state, i.e. when a Port Management message is
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received for that port with the Function field indicating either
Bring Up, or Reset Input Port.
ATM Labels
If a port's attribute PortType=ATM then that port's labels
must be interpreted as ATM Labels as shown:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ - - -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | VPI | VCI |
+ - - -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
ATM ports do not support Extension Lables so the VPI and
VCI values always occupy the 28 bits following the flags in
a connection management message.
ATM distinguishes between virtual path connections and
virtual channel connections. The connection management
messages apply both to virtual channel connections and
virtual path connections. The Add Branch and Move Branch
connection management messages have two Message Types. One
Message Type indicates that a virtual channel connection is
required, and the other Message Type indicates that a
virtual path connection is required. The Delete Branches,
Delete Tree, and Delete All connection management messages
have only a single Message Type because they do not need to
distinguish between virtual channel connections and virtual
path connections. For virtual path connections, neither
Input VCI fields nor Output VCI fields are required. They
should be set to zero by the sender and ignored by the
receiver. Virtual channel branches may not be added to an
existing virtual path connection. Conversely, virtual path
branches may not be added to an existing virtual channel
connection. In the Port Configuration message each switch
input port may declare whether it is capable of supporting
virtual path switching (i.e. accepting connection
management messages requesting virtual path connections).
Other Labels
[Editor's Note: No other label types are currently
defined.]
4.2 Add Branch Message
The Add Branch message is a connection management message used to
establish a connection or to add an additional branch to an
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existing connection. It may also be used to check the connection
state stored in the switch. The connection is specified by the
Input Port and Input Label fields. The output branch is specified
by the Output Port and Output Label fields. The quality of service
requirements of the connection are specified by the QoS Model
Selector and Service Selector fields. To request a connection the
Add Branch message is:
Message Type = 16
If the connection specified by the Input Port and Input Label
fields does not already exist, it must be established with the
single output branch specified in the request message. If the
Bidirectional Flag in the Flags field is set, the reverse
connection must also be established. The output branch should have
the QoS attributes specified by the Class of Service field.
If the connection specified by the Input Port and Input Label
fields already exists, but the specified output branch does not,
the new output branch must be added. The new output branch should
have the QoS attributes specified by the Class of Service field.
If the connection specified by the Input Port and Input Label
fields already exists and the specified output branch also already
exists, the QoS attributes of the connection, specified by the
Class of Service field, if different from the request message,
should be changed to that in the request message. A success
response message must be sent if the Result field of the request
message is "AckAll". This allows the controller to periodically
reassert the state of a connection or to change its priority. If
the result field of the request message is "NoSuccessAck" a
success response message should not be returned. This may be used
to reduce the traffic on the control link for messages that are
reasserting previously established state. For messages that are
reasserting previously established state, the switch must always
check that this state is correctly established in the switch
hardware (i.e. the actual connection tables used to forward
cells).
If the output branch specified by the Output Port and Output Label
fields is already in use by any connection other than that
specified by the Input Port and Input Label fields, then the
resulting output branch will have multiple input branches. If
multiple point-to-point connections share the same output branch
the result will be a multipoint-to-point connection.
If the connection specified by the Input Port and Input Label
fields already exists, and the Bidirectional Flag in the Flags
field is set, a failure response must be returned indicating:
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"Only point-to-point bidirectional connections may be
established."
It should be noted that different switches support multicast in
different ways. There will be a limit to the total number of
point- to-multipoint connections any switch can support, and
possibly a limit on the maximum number of branches that a point-
to-multipoint connection may specify. Some switches also impose a
limit on the number of different Label values that may be assigned
to the output branches of a point-to-multipoint connection. Many
switches are incapable of supporting more than a single branch of
any particular point-to-multipoint connection on the same output
port. Specific failure codes are defined for some of these
conditions.
ATM specific procedures:
To request an ATM virtual path connection the ATM Virtual
Path Connection (VPC) Add Branch message is:
Message Type = 26
An ATM virtual path connection can only be established
between ATM ports, i.e. ports with the "ATM" Label Type
attribute. If an ATM VPC Add Branch message is received and
either the switch input port specified by the Input Port
field or the switch output port specified by the Output
Port field is not an ATM port, a failure response message
must be returned indicating, "Virtual path switching is not
supported on non-ATM ports."
If an ATM VPC Add Branch message is received and the switch
input port specified by the Input Port field does not
support virtual path switching, a failure response message
must be returned indicating, "Virtual path switching is not
supported on this input port."
If an ATM virtual path connection already exists on the
virtual path specified by the Input Port and Input VPI
fields, a failure response message must be returned
indicating, "Attempt to add a virtual channel connection
branch to an existing virtual path connection." For the VPC
Add Branch message, if a virtual channel connection already
exists on any of the virtual channels within the virtual
path specified by the Input Port and Input VPI fields, a
failure response message must be returned indicating,
"Attempt to add a virtual path connection branch to an
existing virtual channel connection."
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4.3 Delete Tree Message
The Delete Tree message is a connection management message used to
delete an entire connection. All remaining branches of the
connection are deleted. A connection is specified by the Input
Port and Input Label fields. The Output Port and Output Label
fields are not used in this message. The Delete Tree message is:
Message Type = 18
If the Result field of the request message is "AckAll" a success
response message must be sent upon successful deletion of the
specified connection. The success message must not be sent until
the delete operation has been completed and if possible, not until
all data on the connection, queued for transmission, has been
transmitted. The Number of Branches field is not used in either
the request or response messages of the Delete Tree message.
4.4 Verify Tree Message
The Verify Tree message has been removed from this version of
GSMP. Its function has been replaced by the Number of Branches
field in the success response to the Add Branch message which
contains the number of branches on a connection after successful
completion of an add branch operation.
Message Type = 19 is reserved.
If a request message is received with Message Type = 19 a failure
response must be returned with the Code field indicating: "The
specified request is not implemented in this version of the
protocol."
4.5 Delete All Message
The Delete All message is a connection management message used to
delete all connections on a switch input port. All connections
that arrive at the specified input port must be deleted. On
completion of the operation all dynamically assigned Label values
for the specified port must be unassigned, i.e. there must be no
connections established in the Label space that GSMP controls on
this port. The Input Label and Output Label fields are not used in
this message. The Delete All message is:
Message Type = 20
If the Result field of the request message is "AckAll" a success
response message must be sent upon completion of the operation.
The Number of Branches field is not used in either the request or
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response messages of the Delete All message. The success response
message must not be sent until the operation has been completed.
The following failure response messages may be returned to a
Delete All request.
The specified request is not implemented on this switch.
One or more of the specified ports does not exist.
Invalid Port Session Number.
If any field in a Delete All message not covered by the above
failure codes is invalid, a failure response must be returned
indicating: "Invalid request message." Else, the delete all
operation must be completed successfully and a success message
returned. No other failure messages are permitted.
4.6 Delete Branches Message
The Delete Branches message is a connection management message
used to request one or more delete branch operations. Each delete
branch operation deletes a branch of a channel, or in the case of
the last branch of a connection, it deletes the connection. The
Delete Branches message is:
Message Type = 17
The request message has the following format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Message Type | Result | Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Number of Elements |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Delete Branch Elements ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Number of Elements
Specifies the number of Delete Branch Elements to follow
in the message. The number of Delete Branch Elements in
a Delete Branches message must not cause the packet
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length to exceed the maximum transmission unit defined
by the encapsulation.
Each Delete Branch Element specifies an output branch to be
deleted and has the following structure:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Port Session Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Input Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|x x|I|O| |
+-+-+-+-+ Input Label ~
~ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Output Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error | |
+-+-+-+-+ Output Label ~
~ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
I: Input Extension Label
The Input Extension Label flag if zero indicates that
the Input Label field is a 28 bit field. If the Input
Extension Label flag is set then the Input Label field
is a 60 bit field structured as a 28 bit first level
label field followed by a 32 bit second level label
field.
O: Output Extension Label
The Output Extension Label flag if zero indicates that
the Output Label field is a 28 bit field. If the Output
Extension Label flag is set then the Output Label field
is a 60 bit field structured as a 28 bit first level
label field followed by a 32 bit second level label
field.
Error
Is used to return a failure code indicating the reason
for the failure of a specific Delete Branch Element in a
Delete Branches failure response message. The Error
field is not used in the request message and must be set
to zero. A value of zero is used to indicate that the
delete operation specified by this Delete Branch Element
was successful. Values for the other failure codes are
specified in Section 3.2, "Failure Response Messages."
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All other fields of the Delete Branch Element have the
same definition as specified for the other connection
management messages.
In each Delete Branch Element, a connection is specified by the
Input Port and Input Label fields. The specific branch to be
deleted is indicated by the Output Port and Output Label fields.
If the Result field of the Delete Branches request message is
"AckAll" a success response message must be sent upon successful
deletion of the branches specified by all of the Delete Branch
Elements. The success response message must not be sent until all
of the delete branch operations have been completed. The success
response message is only sent if all of the requested delete
branch operations were successful. No Delete Branch Elements are
returned in a Delete Branches success response message and the
Number of Elements field must be set to zero.
If there is a failure in any of the Delete Branch Elements a
Delete Branches failure response message must be returned. The
Delete Branches failure response message is a copy of the request
message with the Code field of the entire message set to, "Failure
specific to the particular message type," and the Error field of
each Delete Branch Element indicating the result of each requested
delete operation. A failure in any of the Delete Branch Elements
must not interfere with the processing of any other Delete Branch
Elements.
4.7 Move Branch Message
The Move Branch message is used to move a branch of an existing
connection from its current output port label to a new output port
label in a single atomic transaction. The Move Branch connection
management message has the following format for both request and
response messages:
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Message Type | Result | Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Port Session Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Input Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|x x|E|x| |
+-+-+-+-+ Input Label ~
~ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Old Output Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|x x|E|x| |
+-+-+-+-+ Old Output Label ~
~ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| New Output Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|QMS|E|x| |
+-+-+-+-+ New Output Label ~
~ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number of Branches | Service Selector |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The E, QMS and Service Selector fields are as defined in the Add
Branch message.
The Move Branch message is a connection management message used to
move a single output branch of connection from its current output
port and Output Label, to a new output port and Output Label on
the same connection. None of the connection's other output
branches are modified. When the operation is complete the original
Output Label on the original output port will be deleted from the
connection.
The Move Branch message is:
Message Type = 22
For the Move Branch message, if the connection specified by the
Input Port and Input Label fields already exists, and the output
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branch specified by the Old Output Port and Old Output Label
fields exists as a branch on that connection, the output branch
specified by the New Output Port and New Output Label fields is
added to the connection and the branch specified by the Old Output
Port and Old Output Label fields is deleted. If the Result field
of the request message is "AckAll" a success response message must
be sent upon successful completion of the operation. The success
response message must not be sent until the Move Branch operation
has been completed.
For the Move Branch message, if the connection specified by the
Input Port and Input Label fields already exists, but the output
branch specified by the Old Output Port and Old Output Label
fields does not exist as a branch on that connection, a failure
response must be returned with the Code field indicating, "The
specified branch does not exist."
For the Move Branch message, if the connection specified by the
Input Port and Input Label fields already exists, and the output
branch specified by the Old Output Port and Old Output Label
fields exists as a branch on that connection, the output branch
specified by the New Output Port and New Output Label fields is
added to the connection and the branch specified by the Old Output
Port and Old Output Label fields is deleted. If the Result field
of the request message is "AckAll" a success response message must
be sent upon successful completion of the operation. The success
response message must not be sent until the Move Branch operation
has been completed.
ATM Specific Procedures:
The ATM VPC Move Branch message is a connection management
message used to move a single output branch of a virtual
path connection from its current output port and output
VPI, to a new output port and output VPI on the same
virtual channel connection. None of the other output
branches are modified. When the operation is complete the
original output VPI on the original output port will be
deleted from the connection.
The VPC Move Branch message is:
Message Type = 27
For the VPC Move Branch message, if the virtual path
connection specified by the Input Port and Input VPI fields
already exists, and the output branch specified by the Old
Output Port and Old Output VPI fields exists as a branch on
that connection, the output branch specified by the New
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Output Port and New Output VPI fields is added to the
connection and the branch specified by the Old Output Port
and Old Output VPI fields is deleted. If the Result field
of the request message is "AckAll" a success response
message must be sent upon successful completion of the
operation. The success response message must not be sent
until the Move Branch operation has been completed.
For the VPC Move Branch message, if the virtual path
connection specified by the Input Port and Input VPI fields
already exists, but the output branch specified by the Old
Output Port and Old Output VPI fields does not exist as a
branch on that connection, a failure response must be
returned with the Code field indicating, "The specified
branch does not exist."
If the virtual channel connection specified by the Input
Port and Input Label fields; or the virtual path connection
specified by the Input Port and Input VPI fields; does not
exist, a failure response must be returned with the Code
field indicating, "The specified connection does not
exist."
If the output branch specified by the New Output Port, New
Output VPI, and New Output VCI fields for a virtual channel
connection; or the output branch specified by the New
Output Port and New Output VPI fields for a virtual path
connection; is already in use by any connection other than
that specified by the Input Port and Input Label fields
then the resulting output branch will have multiple input
branches. If multiple point-to-point connections share the
same output branch the result will be a multipoint-to-point
connection. If multiple point-to-multipoint trees share the
same output branches the result will be a multipoint-to-
multipoint connection.
5. Port Management Messages
5.1 Port Management Message
The Port Management message allows a port to be brought into
service, taken out of service, looped back, reset, or the transmit
cell rate changed. Only the Bring Up and the Reset Input Port
functions change the connection state (established connections) on
the input port. Only the Bring Up function changes the value of
the Port Session Number. If the Result field of the request
message is "AckAll" a success response message must be sent upon
successful completion of the operation. The success response
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message must not be sent until the operation has been completed.
The Port Management Message is:
Message Type = 32
The Port Management message has the following format for the
request and success response messages:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Message Type | Result | Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Port Session Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Event Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Event Flags | Duration | Function |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Transmit Cell Rate |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Event Sequence Number
In the success response message gives the current value
of the Event Sequence Number of the switch port
indicated by the Port field. The Event Sequence Number
is set to zero when the port is initialized. It is
incremented by one each time the port detects an
asynchronous event that the switch would normally report
via an Event message. If the Event Sequence Number in
the success response differs from the Event Sequence
Number of the most recent Event message received for
that port, events have occurred that were not reported
via an Event message. This is most likely to be due to
the flow control that restricts the rate at which a
switch can send Event messages for each port. In the
request message this field is not used.
Event FlagsField in the request message is used to reset the Event
Flags in the switch port indicated by the Port field.
Each Event Flag in a switch port corresponds to a type
of Event message. When a switch port sends an Event
message it sets the corresponding Event Flag on that
port. The port is not permitted to send another Event
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message of the same type until the Event Flag has been
reset. If the Function field in the request message is
set to "Reset Event Flags," for each bit that is set in
the Event Flags field, the corresponding Event Flag in
the switch port is reset.
The Event Flags field is only used in a request message
with the Function field set to "Reset Event Flags." For
all other values of the Function field, the Event Flags
field is not used. In the success response message the
Event Flags field must be set to the current value of
the Event Flags for the port, after the completion of
the operation specified by the request message, for all
values of the Function field. Setting the Event Flags
field to all zeros in a "Reset Event Flags" request
message allows the controller to obtain the current
state of the Event Flags and the current Event Sequence
Number of the port without changing the state of the
Event Flags.
The correspondence between the types of Event message
and the bits of the Event Flags field is as follows:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|U|D|I|N|Z|x x x|
+-+-+-+-+-+-+-+-+
U: Port Up Bit 0, (most significant bit)
D: Port Down Bit 1,
I: Invalid Label Bit 2,
N: New Port Bit 3,
Z: Dead Port Bit 4,
x: Unused Bits 5--7.
Duration Is the length of time, in seconds, that any of the
loopback states remain in operation. When the duration
has expired the port will automatically be returned to
service. If another Port Management message is received
for the same port before the duration has expired, the
loopback will continue to remain in operation for the
length of time specified by the Duration field in the
new message. The Duration field is only used in request
messages with the Function field set to Internal
Loopback, External Loopback, or Bothway Loopback.
Function Specifies the action to be taken. The specified action
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will be taken regardless of the current status of the
port (Available, Unavailable, or any Loopback state). If
the specified function requires a new Port Session
Number to be generated, the new Port Session Number must
be returned in the success response message. The defined
values of the Function field are:
Bring Up:
Function = 1. Bring the port into service. All
connections that arrive at the specified input port
must be deleted and a new Port Session Number must
be selected using some form of random number. On
completion of the operation all dynamically
assigned Label values for the specified input port
must be unassigned, i.e. no connections will be
established in the Label space that GSMP controls
on this input port. The Port Status of the port
afterwards will be Available.
Take Down:
Function = 2. Take the port out of service. Any
cells received at this port will be discarded. No
cells will be transmitted from this port. The Port
Status of the port afterwards will be Unavailable.
The behavior is undefined if the port is taken down
over which the GSMP session that controls the
switch is running. (In this case the most probable
behavior would be for the switch either to ignore
the message or to terminate the current GSMP
session and to initiate another session, possibly
with the backup controller, if any.) The correct
method to reset the link over which GSMP is running
is to issue an RSTACK message in the adjacency
protocol.
Internal Loopback:
Function = 3. Cells arriving at the output port
from the switch fabric are looped through to the
input port to return to the switch fabric. All of
the ATM functions of the input port above the
physical layer, e.g. header translation, are
performed upon the looped back cells. The Port
Status of the port afterwards will be Internal
Loopback.
External Loopback:
Function = 4. Cells arriving at the input port from
the external communications link are immediately
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looped back to the communications link at the
physical layer without entering the input port.
None of the ATM functions of the input port above
the physical layer are performed upon the looped
back cells. The Port Status of the port afterwards
will be External Loopback.
Bothway Loopback:
Function = 5. Both internal and external loopback
are performed. The Port Status of the port
afterwards will be Bothway Loopback.
Reset Input Port:
Function = 6. All connections that arrive at the
specified input port must be deleted and the input
and output port hardware re-initialized. On
completion of the operation all dynamically
assigned Label values for the specified input port
must be unassigned, i.e. no connections will be
established in the Label space that GSMP controls
on this input port. The range of VPIs and VCIs that
may be controlled by GSMP on this port will be set
to the default values specified in the Port
Configuration message. The transmit cell rate of
the output port must be set to its default value.
The Port Session Number is not changed by the Reset
Input Port function. The Port Status of the port
afterwards will be Unavailable.
Reset Event Flags:
Function = 7. For each bit that is set in the Event
Flags field, the corresponding Event Flag in the
switch port must be reset. The Port Status of the
port is not changed by this function.
Set Transmit Cell Rate:
Function = 8. Sets the transmit cell rate of the
output port as close as possible to the rate
specified in the Transmit Cell Rate field. In the
success response message the Transmit Cell Rate
must indicate the actual transmit cell rate of the
output port. If the transmit cell rate of the
requested output port cannot be changed, a failure
response must be returned with the Code field
indicating: "The transmit cell rate of this output
port cannot be changed." If the transmit cell rate
of the requested output port can be changed, but
the value of the Transmit Cell Rate field is beyond
the range of acceptable values, a failure response
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must be returned with the Code field indicating:
"Requested transmit cell rate out of range for this
output port." In the failure response message the
Transmit Cell Rate must contain the same value as
contained in the request message that caused the
failure. The transmit cell rate of the output port
is not changed by the Bring Up, Take Down, or any
of the Loopback functions. It is returned to the
default value by the Reset Input Port function.
Transmit Cell Rate
This field is only used in request and success response
messages with the Function field set to "Set Transmit
Cell Rate." It is used to set the output cell rate of
the output port. It is specified in cells/s. If the
Transmit Cell Rate field contains the value 0xFFFFFFFF
the transmit cell rate of the output port should be set
to the highest valid value.
5.2 Label Range Message
[Editor's note: this message is ATM specific. It needs to be
decided if we need such flexibility for non ATM ports. If so, we
could either generalise this message or add similar messages for
non ATM ports.]
The default label range, Min VPI to Max VPI and Min VCI to Max
VCI, is specified for each port by the Port Configuration or the
All Ports Configuration messages. When the protocol is
initialized, before the transmission of any Label Range messages,
the label range of each port will be set to the default label
range. (The default label range is dependent upon the switch
design and configuration and is not specified by the GSMP
protocol.) The Label Range message allows the range of VPIs
supported by a specified port, or the range of VCIs supported by a
specified VPI on a specified port, to be changed. Each switch port
must declare whether it supports the Label Range message in the
Port Configuration or the All Ports Configuration messages. The
Label Range message is:
Message Type = 33
The Label Range message has the following format for the request
and success response messages:
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Message Type | Result | Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Port Session Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Q|V|x x| Min VPI |x x x x| Max VPI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Min VCI | Max VCI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Remaining VPIs | Remaining VCIs |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Flags
Q: Query
If the Query flag is set in a request message, the
switch must respond with the current range of valid
VPIs, or the current range of valid VCIs on a specified
VPI, according to the Label flag. The current label
range is not changed by a request message with the Query
flag set. If the Query flag is zero, the message is
requesting a label change operation.
V: Label
If the Label flag is set, the message refers to a range
of VPIs only. The Min VCI and Max VCI fields are unused.
If the Label flag is zero the message refers to a range
of VCIs on either one VPI or on a range of VPIs.
x: Unused
Min VPI
Max VPI
Specify a range of VPI values, Min VPI to Max VPI
inclusive. A single VPI may be specified with a Min VPI
and a Max VPI having the same value. In a request
message, if the value of the Max VPI field is less than
or equal to the value of the Min VPI field, the
requested range is a single VPI with a value equal to
the Min VPI field. Zero is a valid value. In a request
message, if the Query flag is set, and the Label flag is
zero, the Max VPI field specifies a single VPI and the
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Min VPI field is not used. The maximum valid value of
these fields for both request and response messages is
0xFFF.
Min VCI
Max VCI
Specify a range of VCI values, Min VCI to Max VCI
inclusive. A single VCI may be specified with a Min VCI
and a Max VCI having the same value. In a request
message, if the value of the Max VCI field is less than
or equal to the value of the Min VCI field, the
requested range is a single VCI with a value equal to
the Min VCI field. Zero is a valid value. (However,
VPI=0, VCI=0 is not available as a virtual channel
connection as it is used as a special value in ATM to
indicate an unassigned cell.)
Remaining VPIs
Remaining VCIs
These fields are unused in the request message. In the
success response message and in the failure response
message these fields give the maximum number of
remaining VPIs and VCIs that could be requested for
allocation on the specified port (after completion of
the requested operation in the case of the success
response). It gives the switch controller an idea of how
many VPIs and VCIs it could request. The number given is
the maximum possible given the constraints of the switch
hardware. There is no implication that this number of
VPIs and VCIs is available to every switch port.
If the Query flag and the Label flag are set in the request
message, the switch must reply with a success response message
containing the current range of valid VPIs that are supported by
the port. The Min VPI and Max VPI fields are not used in the
request message.
If the Query flag is set and the Label flag is zero in the request
message, the switch must reply with a success response message
containing the current range of valid VCIs that are supported by
the VPI specified by the Max VPI field. If the requested VPI is
invalid, a failure response must be returned indicating: "One or
more of the specified input VPIs is invalid." The Min VPI field is
not used in either the request or success response messages.
If the Query flag is zero and the Label flag is set in the request
message, the Min VPI and Max VPI fields specify the new range of
VPIs to be allocated to the input port specified by the Port
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field. Whatever the range of VPIs previously allocated to this
port it should be increased or decreased to the specified value.
If the Query flag and the Label flag are zero in the request
message, the Min VCI and Max VCI fields specify the range of VCIs
to be allocated to each of the VPIs specified by the VPI range.
Whatever the range of VCIs previously allocated to each of the
VPIs within the specified VPI range on this port, it should be
increased or decreased to the specified value. The allocated VCI
range must be the same on each of the VPIs within the specified
VPI range.
The success response to a Label Range message requesting a change
of label range is a copy of the request message with the Remaining
VPIs and Remaining VCIs fields updated to the new values after the
Label Range operation.
If the switch is unable to satisfy a request to change the VPI
range, it must return a failure response message with the Code
field set to "Cannot support requested VPI range." In this failure
response message the switch must use the Min VPI and Max VPI
fields to suggest a VPI range that it would be able to satisfy.
If the switch is unable to satisfy a request to change the VCI
range on all VPIs within the requested VPI range, it must return a
failure response message with the Code field set to "Cannot
support requested VCI range on all requested VPIs." In this
failure response message the switch must use the Min VPI, Max VPI,
Min VCI, and Max VCI fields to suggest a VPI and VCI range that it
would be able to satisfy.
In all other failure response messages for the label range
operation the switch must return the values of Min VPI, Max VPI,
Min VCI, and Max VCI from the request message.
While switches can typically support all 256 or 4096 VPIs the VCI
range that can be supported is often more constrained. Often the
Min VCI must be 0 or 32. Typically all VCIs within a particular
VPI must be contiguous. The hint in the failure response message
allows the switch to suggest a label range that it could satisfy
in view of its particular architecture.
While the Label Range message is defined to specify both a range
of VPIs and a range of VCIs within each VPI, the most likely use
is to change either the VPI range or the range of VCIs within a
single VPI. It is possible for a VPI to be valid but to be
allocated no valid VCIs. Such a VPI could be used for a virtual
path connection but to support virtual channel connections it
would need to be allocated a range of VCIs.
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A Label Range request message may be issued regardless of the Port
Status or the Line Status of the target switch port. If the Port
field of the request message contains an invalid port (a port that
does not exist or a port that has been removed from the switch) a
failure response message must be returned with the Code field set
to, "One or more of the specified ports does not exist."
6. State and Statistics Messages
The state and statistics messages permit the controller to request
the values of various hardware counters associated with the switch
input and output ports and connections. They also permit the
controller to request the connection state of a switch input port.
The Connection Activity message is used to determine whether one
or more specific connections have recently been carrying traffic.
The Statistics message is used to query the various port and
connection traffic and error counters.
The Report Connection State message is used to request an input
port to report the connection state for a single connection, a
single ATM virtual path connection, or for the entire input port.
6.1 Connection Activity Message
The Connection Activity message is used to determine whether one
or more specific connections have recently been carrying traffic.
The Connection Activity message contains one or more Activity
Records. Each Activity Record is used to request and return
activity information concerning a single connection. Each
connection is specified by its input port and Input Label which
are specified in the Input Port and Input Label fields of each
Activity Record.
Two forms of activity detection are supported. If the switch
supports per connection traffic accounting, the current value of
the traffic counter for each specified connection must be
returned. The units of traffic counted are not specified but will
typically be either cells or frames. The controller must compare
the traffic counts returned in the message with previous values
for each of the specified connections to determine whether each
connection has been active in the intervening period. If the
switch does not support per connection traffic accounting, but is
capable of detecting per connection activity by some other
unspecified means, the result may be indicated for each connection
using the Flags field. The Connection Activity message is:
Message Type = 48
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The Connection Activity request and success response messages have
the following format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Message Type | Result | Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number of Records | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Activity Records ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Number of Records
Field specifies the number of Activity Records to
follow. The number of Activity records in a single
Connection Activity message must not cause the packet
length to exceed the maximum transmission unit defined
by the encapsulation.
Each Activity Record has the following format:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Input Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|V|C|A|E| |
+-+-+-+-+ Input Label ~
~ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Traffic Count +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Input Port
Identifies the port number of the input port on which
the connection of interest arrives in order to identify
the connection (regardless of whether the traffic count
for the connection is maintained on the input port or
the output port).
Input Label
Fields identify the specific connection for which
statistics are being requested.
Flags
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V: Valid Record
In the success response message the Valid Record flag is
used to indicate an invalid Activity Record. The flag
must be zero if any of the fields in this Activity
Record are invalid, if the input port specified by the
Input Port field does not exist, or if the specified
connection does not exist. If the Valid Record flag is
zero in a success response message, the Counter flag,
the Activity flag, and the Traffic Count field are
undefined. If the Valid Record flag is set, the Activity
Record is valid, and the Counter and Activity flags are
valid. The Valid Record flag is not used in the request
message.
C: Counter
In a success response message, if the Valid Record flag
is set, the Counter flag, if zero, indicates that the
value in the Traffic Count field is valid. If set, it
indicates that the value in the Activity flag is valid.
The Counter flag is not used in the request message.
A: Activity
In a success response message, if the Valid Record and
Counter flags are set, the Activity flag, if set,
indicates that there has been some activity on this
connection since the last Connection Activity message
for this connection. If zero, it indicates that there
has been no activity on this connection since the last
Connection Activity message for this connection. The
Activity flag is not used in the request message.
E: Extension Label
The Extension Label flag if zero indicates that the
Input Label field is a 28 bit field. If the Extension
Label flag is set then the Input Label field is a 60 bit
field structured as a 28 bit first level label field
followed by a 32 bit second level label field.
Traffic Count
Field is not used in the request message. In the success
response message, if the switch supports per connection
traffic counting, the Traffic Count field must be set to
the value of a free running, connection specific, 64-bit
traffic counter counting traffic flowing across the
specified connection. The value of the traffic counter
is not modified by reading it. If per connection traffic
counting is supported, the switch must report the
Connection Activity result using the traffic count
rather than using the Activity flag.
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The format of the failure response is the same as the request
message with the Number of Records field set to zero and no
Connection Activity records returned in the message. If the switch
is incapable of detecting per connection activity, a failure
response must be returned indicating, "The specified request is
not implemented on this switch."
6.2 Statistics Messages
The Statistics messages are used to query the various port and
connection and error counters.
The Statistics request messages have the following format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Message Type | Result | Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|x x x|E| |
+-+-+-+-+ Label ~
~ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
E: Extension Label
The Extension Label flag if zero indicates that the
Label field is a 28 bit field. If the Extension Label
flag is set then the Label field is a 60 bit field
structured as a 28 bit first level label field followed
by a 32 bit second level label field.
Label
The Label Field identifies the specific connection for
which statistics are being requested.
The success response for the Statistics message has the following
format:
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Message Type | Result | Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|x x x|E| |
+-+-+-+-+ Label ~
~ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Input Cell Count +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Input Frame Count +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Input Cell Discard Count +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Input Frame Discard Count +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ ATM HEC Error Count +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Input Invalid Label Count +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Output Cell Count +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Output Frame Count +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Output Cell Discard Count +
| |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Output Frame Discard Count +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
EPort
Label
Fields are the same as those of the request message.
Input Cell Count
Output Cell Count
Give the value of a free running 64-bit counter counting
cells arriving at the input or departing from the output
respectively.
Input Frame Count
Output Frame Count
Give the value of a free running 64-bit counter counting
frames (packets) arriving at the input or departing from
the output respectively.
Input Cell Discard Count
Output Cell Discard Count
Give the value of a free running 64-bit counter counting
cells discarded due to queue overflow on an input port
or on an output port respectively.
Input Frame Discard Count
Output Frame Discard Count
Give the value of a free running 64-bit counter counting
frames discarded due to congestion on an input port or
on an output port respectively.
ATM HEC Error Count
Gives the value of a free running 64-bit counter
counting ATM cells discarded due to header checksum
errors on arrival at an input port.
Invalid Label Count
Gives the value of a free running 64-bit counter
counting cells or frames discarded because their Label
is invalid on arrival at an input port.
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6.2.1 Port Statistics Message
The Port Statistics message requests the statistics for the switch
port specified in the Port field. The contents of the Label field
in the Port Statistics request message is ignored. All of the
count fields in the success response message refer to per-port
counts regardless of the connection to which the cells or frames
belong. Any of the count fields in the success response message
not supported by the port must be set to zero. The Port Statistics
message is:
Message Type = 49
6.2.2 Connection Statistics Message
The Connection Statistics message requests the statistics for the
connection specified in the Label field that arrives on the switch
input port specified in the Port field. All of the count fields in
the success response message refer only to the specified
connection. The ATM HEC Error Count and Invalid Label Count fields
are not connection specific and must be set to zero. Any of the
other count fields not supported on a per connection basis must be
set to zero in the success response message. The Connection
Statistics message is:
Message Type = 50
6.2.3 QoS Class Statistics Message
The QoS Class Statistics message is not supported in this version
of GSMP.
Message Type = 51 is reserved.
6.3 Report Connection State Message
The Report Connection State message is used to request an input
port to report the connection state for a single connection, a
single ATM virtual path connection, or for the entire input port.
The Report Connection State message is:
Message Type = 52
The Report Connection State request message has the following
format:
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Message Type | Result | Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Input Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A|V|x|E| |
+-+-+-+-+ Input Label ~
~ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Input PortIdentifies the port number of the input port for which
the connection state is being requested.
Flags
A: All Connections
If the All Connections flag is set, the message requests
the connection state for all connections that arrive at
the input port specified by the Input Port field. In
this case the Input Label field and the Label flag are
unused.
V: ATM VPI
The ATM VPI flag may only be set for ports with
PortType=ATM. If the switch recieves a Report Connection
State message in which the ATM VPI flag set and in which
the input port specified by the Input Port field does
not have PortType=ATM, the switch must return an Error
Message "xxxxxx".
If the All Connections flag is zero and the ATM VPI flag
is also zero, the message requests the connection state
for the connection that arrives at the input port
specified by the Port and Input Label fields.
ATM specific procedures:
If the All Connections flag is zero and the ATM VPI
flag is set and the input port specified by the Input
Port field has LabelType=ATM, the message requests
the connection state for the virtual path connection
that arrives at the input port specified by the Input
Port and Input VPI fields. If the specified Input VPI
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identifies an ATM virtual path connection (i.e. a
single switched virtual path) the state for that
connection is requested. If the specified Input VPI
identifies a virtual path containing virtual channel
connections, the message requests the connection
state for all virtual channel connections that belong
to the specified virtual path.
x: Unused.
E: Extension Label
The Extension Label flag if zero indicates that the
Input Label field is a 28 bit field. If the Extension
Label flag is set then the Input Label field is a 60 bit
field structured as a 28 bit first level label field
followed by a 32 bit second level label field.
Input Label
Field identifies the specific connection for which
connection state is being requested. For a virtual path
connection (switched as a single virtual path
connection) or a virtual path (switched as one or more
virtual channel connections within the virtual path) the
Input VCI field is not used. For requests that do not
require a virtual path connection or virtual channel
connection to be specified, the Input VPI and Input VCI
fields are not used.
The Report Connection State success response message has the
following format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Message Type | Result | Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Input Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Connection Records ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Input PortIs the same as the Input Port field in the request
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message. It identifies the port number of the input port
for which the connection state is being reported.
Sequence Number
In the case that the requested connection state cannot
be reported in a single success response message, each
successive success response message in reply to the same
request message must increment the Sequence Number. The
Sequence Number of the first success response message,
in response to a new request message, must be zero.
Connection Records
Each success response message must contain one or more
Connection Records. Each Connection Record specifies a
single point-to-point or point-to-multipoint connection.
The number of Connection Records in a single Report
Connection State success response must not cause the
packet length to exceed the maximum transmission unit
defined by the encapsulation. If the requested
connection state cannot be reported in a single success
response message, multiple success response messages
must be sent. All success response messages that are
sent in response to the same request message must have
the same Input Port and Transaction Identifier fields as
the request message. A single Connection Record must not
be split across multiple success response messages. The
More flag of the last Connection Record in a success
response message indicates whether the response to the
request has been completed or whether one or more
further success response messages should be expected in
response to the same request message.
Each Connection Record has the following format:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A|V|P|M| Input VPI | Input VCI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Output Branch Records ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
[Editor's note: help, where do i put the extension label flag?]
Flags
A: All Connections
V: ATM VPI
For the first Connection Record in each success response
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message the All Connections and the ATM VPI flags must
be the same as those of the request message. For
successive Connection Records in the same success
response message these flags are not used.
P: ATM VPC
The ATM VPC flag, if set and only if set, indicates that
the Connection Record refers to an ATM virtual path
connection.
M: More
If the More flag is set, it indicates that another
Connection Record, in response to the same request
message, will follow either in the same success response
message or in a successive success response message. If
the More flag is zero it indicates that this is the last
Connection record in this success response message and
that no further success response messages will be sent
in response to the current request message. It indicates
that the response to the request message is now
complete.
Input Label
The input label of the connection specified in this
Connection Record. If this Connection Record specifies a
virtual path connection (the VPC flag is set) the Input
VCI field is unused.
Output Branch Records
Each Connection Record must contain one or more Output
Branch Records. Each Output Branch Record specifies a
single output branch belonging to the connection
identified by the Input Label field of the Connection
Record and the Input Port field of the Report Connection
State message. A point-to-point connection will require
only a single Output Branch Record. A point-to-
multipoint connection will require multiple Output
Branch Records. The last Output Branch Record of each
Connection Record is indicated by the Last Branch flag
of the Output Branch Record. If a point-to-multipoint
connection has more output branches than can fit in a
single Connection Record contained within a single
success response message, that connection may be
reported using multiple Connection Records in multiple
success response messages.
Each Output Branch Record has the following format:
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Output Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L|x x|E| |
+-+-+-+-+ Output Label ~
~ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Output PortThe output port of the switch to which this output
branch is routed.
Flags
L: Last Branch
The Last Branch flag, if set, indicates that this is the
last Output Branch Record of this Connection Record. If
zero, it indicates that one or more further Output
Branch Records are to follow. If this is the last Output
Branch Record in the message and the Last Branch flag is
zero, further output branches belonging to the same
connection will be given in another Connection Record.
This Connection Record will be the first Connection
Record in the next success response message. This
Connection Record must have the same Input VPI and Input
VCI values as the current Connection Record.
E: Extension Label
The Extension Label flag if zero indicates that the
Output Label field is a 28 bit field. If the Extension
Label flag is set then the Input Label field is a 60 bit
field structured as a 28 bit first level label field
followed by a 32 bit second level label field.
x: Unused.
Output Label
The output label of the output branch specified in this
Output Branch Record.
ATM specific procedures:
If this Output Branch Record is part of a
Connection Record that specifies a virtual path
connection (the ATM VPC flag is set) the Output VCI
field is unused.
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A Report Connection State request message may be issued regardless
of the Port Status or the Line Status of the target switch port.
If the Input Port of the request message is valid, and the All
Connections flag is set, but there are no connections established
on that port, a failure response message must be returned with the
code field set to, "Failure specific to the particular message
type." For the Report Connection State message, this failure code
indicates that no connections matching the request message were
found. This failure message should also be returned if the Input
Port of the request message is valid, the All Connections flag is
zero, and no connections are found on that port matching the
specified virtual path connection, virtual path, or virtual
channel connection.
7. Configuration Messages
The configuration messages permit the controller to discover the
capabilities of the switch. Three configuration request messages
have been defined: Switch, Port, and All Ports.
All configuration request messages have the following format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Message Type | Result | Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
7.1 Switch Configuration Message
The Switch Configuration message requests the global (non port-
specific) configuration for the switch. The Switch Configuration
message is:
Message Type = 64
The Port field is not used in the request message.
The Switch Configuration success response message has the
following format:
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Message Type | Result | Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Firmware Version Number | Window Size |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Switch Type | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| Switch Name |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Firmware Version Number
The version number of the switch control firmware
installed.
Window Size
The maximum number of unacknowledged request messages
that may be transmitted by the controller without the
possibility of loss. This field is used to prevent
request messages being lost in the switch because of
overflow in the receive buffer. The field is a hint to
the controller. If desired, the controller may
experiment with higher and lower window sizes to
determine heuristically the best window size.
[editor's note: some text may be added here with regard
to the tcp/ip encapsulation since if tcp is used then
the switch may adjust the reciever window size.]
Switch Type
A 16-bit field allocated by the manufacturer of the
switch. (For these purposes the manufacturer of the
switch is assumed to be the organization identified by
the OUI in the Switch Name field.) The Switch Type
identifies the product. When the Switch Type is combined
with the OUI from the Switch Name the product is
uniquely identified. Network Management may use this
identification to obtain product related information
from a database.
Switch Name
A 48-bit quantity that is unique within the operational
context of the device. A 48-bit IEEE 802 MAC address, if
available, may be used as the Switch Name. The most
significant 24 bits of the Switch Name must be an
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Organizationally Unique Identifier (OUI) that identifies
the manufacturer of the switch.
7.2 Port Configuration Message
The Port Configuration message requests the switch for the
configuration information of a single switch port. The Port field
in the request message specifies the port for which the
configuration is requested. The Port Configuration message is:
Message Type = 65.
The Port Configuration success response message has the following
format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Message Type | Result | Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Port Session Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PortType |S|x x x x x x x| Data Fields Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ PortType Specific Data ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Service Model Data ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Port
The switch port to which the configuration information
refers. Configuration information relating to both the
input and the output sides of the switch port is given.
Port numbers are 32 bits wide and allocated by the
switch. The switch may choose to structure the 32 bits
into subfields that have meaning to the physical
structure of the switch hardware (e.g. physical slot and
port). This structure may be indicated in the Physical
Slot Number and Physical Port Number fields.
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PortType
[Editor's note: words to be written. also, somewhere in
chapter 1 or so we will need text that explains that
certain protocol elements depend on the PortType value.]
PortType = 0d01 = ATM
S: Service Model
If set, indicates that service model data follows the
PortSpecific port configuration data.
Data Fields Length
The total length in bytes of the combined PortType
Specific Data and Service Model Data fields. The length
of each of these fields may be derived from the other
data so the value of Data Fields Length serves primarily
as a check and to assist parsing of the All Ports
Configuration message success response.
PortType Specific Data
This field contains the configuration data specific to
the particular port type as specified by the PortType
field. The field format and length depends also on the
value of PortType. PortType Specific Data is defined
below.
Service Model Data
This field contains data that describes the services
within the Service Model that can be supported by the
port. The length of this field is variable.
[Editor's note: beyond the above sentences no definition
of the service model has been provided in this revision
of the draft. this will be extended in future
revisions.]
7.2.1 PortType Specific Data
The length, format and semantics of the PortType Specific Data
field in the Port Configuration message suffess response and in
the Port Records of the All Port Configuration message success
response all depend on the PortType value of the same message or
record respectively. The specification of the PortType Specific
Data field for each defined PortType value are given in the
subsequent subsections.
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7.2.1.1 PortType Specific Data for PortType=ATM
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|V|M|L|R| Min VPI |Q|x x x| Max VPI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Min VCI | Max VCI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Receive Cell Rate |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Transmit Cell Rate |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Port Status | Line Type | Line Status | Priorities |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Physical Slot Number | Physical Port Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Flags
V: VP Switching
The VP Switching flag, if set, indicates that this input
port is capable of supporting virtual path switching.
Else, if zero, it indicates that this input port is only
capable of virtual channel switching.
M: Multicast Labels
The Multicast Labels flag, if set, indicates that this
output port is capable of labelling each output branch
of a point-to-multipoint tree with a different label. If
zero, it indicates that this output port is not able to
label each output branch of a point-to-multipoint tree
with a different label.
L: Logical Multicast
The Logical Multicast flag, if set, indicates that this
output port is capable of supporting more than a single
branch from any point-to-multipoint connection. This
capability is often referred to as logical multicast. If
zero, it indicates that this output port can only
support a single output branch from each point-to-
multipoint connection.
R: Label Range
The Label Range flag, if set, indicates that this switch
port is capable of reallocating its VPI label range or
its VCI label range and therefore accepts the Label
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Range message. Else, if zero, it indicates that this
port does not accept Label Range messages.
Q: QoS
The QoS flag, if set, indicates that this switch port is
capable of handling the Quality of Service messages
defined in section 9 of this specification. Else, if
zero, it indicates that this port does not accept the
Quality of Service messages.
x: Unused
Min VPI
The default minimum value of dynamically assigned
incoming VPI that the connection table on the input port
supports and that may be controlled by GSMP. This value
is not changed as a result of the Label Range message.
Max VPI
The default maximum value of dynamically assigned
incoming VPI that the connection table on the input port
supports and that may be controlled by GSMP. This value
is not changed as a result of the Label Range message.
At power-on, after a hardware reset, and after the Reset
Input Port function of the Port Management message, the
input port must handle all values of VPI within the
range Min VPI to Max VPI inclusive and GSMP must be able
to control all values within this range. It should be
noted that the range Min VPI to Max VPI refers only to
the incoming VPI range that can be supported by the
associated port. No restriction is placed on the values
of outgoing
VPIs that may be written into the cell header. If the
switch does not support virtual paths it is acceptable
for both Min VPI and Max VPI to specify the same value,
most likely zero.
Use of the Label Range message allows the range of VPIs
supported by the port to be changed. However, the Min
VPI and Max VPI fields in the Port Configuration and All
Ports Configuration messages always report the same
default values regardless of the operation of the Label
Range message.
Min VCI
The default minimum value of dynamically assigned
incoming VCI that the connection table on the input port
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can support and may be controlled by GSMP. This value is
not changed as a result of the Label Range message.
Max VCI
The default maximum value of dynamically assigned
incoming VCI that the connection table on the input port
can support and may be controlled by GSMP. This value is
not changed as a result of the Label Range message.
At power-on, after a hardware reset, and after the Reset
Input Port function of the Port Management message, the
input port must handle all values of VCI within the
range Min VCI to Max VCI inclusive, for each of the
virtual paths in the range Min VPI to Max VPI inclusive,
and GSMP must be able to control all values within this
range. It should be noted that the range Min VCI to Max
VCI refers only to the incoming VCI range that can be
supported by the associated port on each of the virtual
paths in the range Min VPI to Max VPI. No restriction is
placed on the values of outgoing VCIs that may be
written into the cell header.
Use of the Label Range message allows the range of VCIs
to be changed on each VPI supported by the port.
However, the Min VCI and Max VCI fields in the Port
Configuration and All Ports Configuration messages
always report the same default values regardless of the
operation of the Label Range message.
For a port over which the GSMP protocol is operating,
the VCI of the GSMP control channel may or may not be
reported as lying within the range Min VCI to Max VCI. A
switch should honor a connection request message that
specifies the VCI value of the GSMP control channel even
if it lies outside the range Min VCI to Max VCI.
Receive Cell Rate
The maximum rate of cells that may arrive at the input
port in cells/s.
Transmit Cell Rate
The maximum rate of cells that may depart from the
output port in cells/s. (The transmit cell rate of the
output port may be changed by the Set Transmit Cell Rate
function of the Port Management message.)
Port Status
Gives the administrative state of the port. The defined
values of the Port Status field are:
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Available:
Port Status = 1. The port is available to both send
and receive cells. When a port changes to the
Available state from any other administrative
state, all dynamically assigned connections must be
cleared and a new Port Session Number must be
generated.
Unavailable:
Port Status = 2. The port has intentionally been
taken out of service. No cells will be transmitted
from this port. No cells will be received by this
port.
Internal Loopback:
Port Status = 3. The port has intentionally been
taken out of service and is in internal loopback:
cells arriving at the output port from the switch
fabric are looped through to the input port to
return to the switch fabric. All of the ATM
functions of the input port above the physical
layer, e.g. header translation, are performed upon
the looped back cells.
External Loopback:
Port Status = 4. The port has intentionally been
taken out of service and is in external loopback:
cells arriving at the input port from the external
communications link are immediately looped back to
the communications link at the physical layer
without entering the input port. None of the ATM
functions of the input port above the physical
layer are performed upon the looped back cells.
Bothway Loopback:
Port Status = 5. The port has intentionally been
taken out of service and is in both internal and
external loopback.
The Port Status of the port over which the GSMP session
controlling the switch is running, must be declared
Available. The controller will ignore any other Port
status for this port. The Port Status of switch ports
after power-on initialization is not defined by GSMP.
Line Type
The type of physical transmission interface for this
port. The values for this field are defined by the
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atmIfType object specified in the Ipsilon IP Switch MIB
[4].
Line Status
The status of the physical transmission medium connected
to the port. The defined values of the Line Status field
are:
Up: Line Status = 1. The line is able to both send and
receive cells. When the Line Status changes to Up
from either the Down or Test states, a new Port
Session Number must be generated.
Down:Line Status = 2. The line is unable either to send
or receive cells or both.
Test:Line Status = 3. The port or line is in a test
mode, for example, power-on test.
PrioritiesThe number of different priority levels that this output
port can assign to connections. Zero is invalid in this
field. If an output port is able to support "Q"
priorities, the highest priority is numbered zero and
the lowest priority is numbered "Q-1". The ability to
offer different qualities of service to different
connections based upon their priority is assumed to be a
property of the output port of the switch. It may be
assumed that for connections that share the same output
port, an ATM cell on a connection with a higher priority
is much more likely to exit the switch before an ATM
cell on a connection with a lower priority if they are
both in the switch at the same time.
Physical Slot Number
The physical location of the slot in which the port is
located. It is an unsigned 16-bit integer that can take
any value except 0xFFFF. The value 0xFFFF is used to
indicate "unknown." The Physical Slot Number is not used
by the GSMP protocol. It is provided to assist network
management in functions such as logging, port naming,
and graphical representation.
Physical Port Number
The physical location of the port within the slot in
which the port is located. It is an unsigned 16-bit
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integer that can take any value except 0xFFFF. The value
0xFFFF is used to indicate "unknown." The Physical Port
Number is not used by the GSMP protocol. It is provided
to assist network management in functions such as
logging, port naming, and graphical representation.
There must be a one to one mapping between Port Number
and the Physical Slot Number and Physical Port Number
combination. Two different Port Numbers must not yield
the same Physical Slot Number and Physical Port Number
combination. The same Port Number must yield the same
Physical Slot Number and Physical Port Number within a
single GSMP session. If both Physical Slot Number and
Physical Port Number indicate "unknown" the physical
location of switch ports may be discovered by looking up
the product identity in a database to reveal the
physical interpretation of the 32-bit Port Number.
7.3 All Ports Configuration Message
The All Ports Configuration message requests the switch for the
configuration information of all of its ports. The All Ports
Configuration message is:
Message Type = 66
The Port field is not used in the request message.
The All Ports Configuration success response message has the
following format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Message Type | Result | Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number of Records | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Port Records ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Number of Records
Field gives the total number of Port Records to be
returned in response to the All Ports Configuration
request message. The number of port records in a single
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All Ports Configuration success response must not cause
the packet length to exceed the maximum transmission
unit defined by the encapsulation. If a switch has more
ports than can be sent in a single success response
message it must send multiple success response messages.
All success response messages that are sent in response
to the same request message must have the same
Transaction Identifier as the request message and the
same value in the Number of Records field. All success
response messages that are sent in response to the same
request message, except for the last message, must have
the result field set to "More." The last message, or a
single success response message, must have the result
field set to "Success." All Port records within a
success response message must be complete, i.e. a single
Port record must not be split across multiple success
response messages.
Port Records
Follow in the remainder of the message. Each port record
has the following format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Port Session Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PortType |S|x x x x x x x| Data Fields Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ PortType Specific Data ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Service Model Data ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The definition of the fields in the Port Record is exactly the
same as that of the Port Configuration message.
8. Event Messages
Event messages allow the switch to inform the controller of
certain asynchronous events. Event messages are not acknowledged.
The Result field and the Code field in the message header are not
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used and should be set to zero. Event messages are not sent during
initialization. Event messages have the following format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Message Type | Result | Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Port Session Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Event Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|x x x|E| |
+-+-+-+-+ Label ~
~ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Event Sequence Number
The current value of the Event Sequence Number for the
specified port. The Event Sequence Number is set to zero
when the port is initialized. It is incremented by one
each time the port detects an asynchronous event that
the switch would normally report via an Event message.
The Event Sequence Number must be incremented each time
an event occurs even if the switch is prevented from
sending an Event message due to the action of the flow
control.
E: Extension Label
The Extension Label flag if zero indicates that the
Label field is a 28 bit field. If the Extension Label
flag is set then the Label field is a 60 bit field
structured as a 28 bit first level label field followed
by a 32 bit second level label field.
Label
Field gives the Label to which the event message refers.
If this field is not required by the event message it is
set to zero.
Each switch port must maintain an Event Sequence Number and a set
of Event Flags, one Event Flag for each type of Event message.
When a switch port sends an Event message it must set the Event
Flag on that port corresponding to the type of the event. The port
is not permitted to send another Event message of the same type
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until the Event Flag has been reset. Event Flags are reset by the
"Reset Event Flags" function of the Port Management message. This
is a simple flow control preventing the switch from flooding the
controller with event messages. The Event Sequence Number of the
port must be incremented every time an event is detected on that
port even if the port is prevented from reporting the event due to
the action of the flow control. This allows the controller to
detect that it has not been informed of some events that have
occurred on the port due to the action of the flow control.
8.1 Port Up Message
The Port Up message informs the controller that the Line Status of
a port has changed from either the Down or Test state to the Up
state. When the Line Status of a switch port changes to the Up
state from either the Down or Test state a new Port Session Number
must be generated, preferably using some form of random number.
The new Port Session Number is given in the Port Session Number
field. The Label field is not used and is set to zero. The Port Up
message is:
Message Type = 80
8.2 Port Down Message
The Port Down message informs the controller that the Line Status
of a port has changed from the Up state to the Down state. This
message will be sent to report link failure if the switch is
capable of detecting link failure. The port session number that
was valid before the port went down is reported in the Port
Session Number field. The Label field is not used and is set to
zero. The Port Down message is:
Message Type = 81
8.3 Invalid Label Message
The Invalid Label message is sent to inform the controller that
one or more cells or frames have arrived at an input port with a
Label that is currently not allocated to an assigned connection.
The input port is indicated in the Port field, and the Label in
the Label field. The Invalid Label message is:
Message Type = 82
8.4 New Port Message
The New Port message informs the controller that a new port has
been added to the switch. The port number of the new port is given
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in the Port field. A new Port Session Number must be assigned,
preferably using some form of random number. The new Port Session
Number is given in the Port Session Number field. The state of the
new port is undefined so the Label field is not used and is set to
zero. The New Port message is:
Message Type = 83
8.5 Dead Port Message
The Dead Port message informs the controller that a port has been
removed from the switch. The port number of the port is given in
the Port field. The Port Session Number that was valid before the
port was removed is reported in the Port Session Number field. The
Label fields are not used and are set to zero. The Dead Port
message is:
Message Type = 84
9. Service Model Definition
10. Adjacency Protocol
The adjacency protocol is used to synchronize state across the
link, to agree on which version of the protocol to use, to
discover the identity of the entity at the other end of a link,
and to detect when it changes. GSMP is a hard state protocol. It
is therefore important to detect loss of contact between switch
and controller, and to detect any change of identity of switch or
controller. No GSMP messages other than those of the adjacency
protocol may be sent across the link until the adjacency protocol
has achieved synchronization.
10.1 Packet Format
All GSMP messages belonging to the adjacency protocol have the
following structure:
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Message Type | Timer |M| Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sender Name |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| Receiver Name |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sender Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Receiver Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sender Instance |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Receiver Instance |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Version
In the adjacency protocol the Version field is used for
version negotiation. In a SYN message the Version field
always contains the highest version understood by the
sender. A receiver receiving a SYN message with a
version higher than understood will ignore that message.
A receiver receiving a SYN message with a version lower
than its own highest version, but a version that it
understands, will reply with a SYNACK with the version
from the received SYN in its GSMP Version field. This
defines the version of the GSMP protocol to be used
while the adjacency protocol remains synchronized. All
other messages will use the agreed version in the
Version field.
The version number for the version of the GSMP protocol
defined by this specification is Version = 2.
Message Type
The adjacency protocol is:
Message Type = 10
Timer
The Timer field is used to inform the receiver of the
timer value used in the adjacency protocol of the
sender. The timer specifies the nominal time between
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periodic adjacency protocol messages. It is a constant
for the duration of a GSMP session. The timer field is
specified in units of 100ms.
M-Flag
The M-Flag is used in the SYN message to indicate
whether the sender is a master or a slave. If the M-Flag
is set in the SYN message, the sender is a master. If
zero, the sender is a slave. The GSMP protocol is
asymmetric, the controller being the master and the
switch being the slave. The M-Flag prevents a master
from synchronizing with another master, or a slave with
another slave. If a slave receives a SYN message with a
zero M-Flag, it must ignore that SYN message. If a
master receives a SYN message with the M-Flag set, it
must ignore that SYN message. In all other messages the
M-Flag is not used.
Code
Field specifies the function of the message. Four Codes
are defined for the adjacency protocol:
SYN: Code = 1
SYNACK: Code = 2
ACK: Code = 3
RSTACK: Code = 4.
Sender Name
For the SYN, SYNACK, and ACK messages, is the name of
the entity sending the message. The Sender Name is a 48-
bit quantity that is unique within the operational
context of the device. A 48-bit IEEE 802 MAC address, if
available, may be used for the Sender Name. If the
Ethernet encapsulation is used the Sender Name must be
the Source Address from the MAC header. For the RSTACK
message, the Sender Name field is set to the value of
the Receiver Name field from the incoming message that
caused the RSTACK message to be generated.
Receiver Name
For the SYN, SYNACK, and ACK messages, is the name of
the entity that the sender of the message believes is at
the far end of the link. If the sender of the message
does not know the name of the entity at the far end of
the link, this field should be set to zero. For the
RSTACK message, he Receiver Name field is set to the
value of the Sender Name field from the incoming message
that caused the RSTACK message to be generated.
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Sender Port
For the SYN, SYNACK, and ACK messages, is the local port
number of the link across which the message is being
sent. For the RSTACK message, the Sender Port field is
set to the value of the Receiver Port field from the
incoming message that caused the RSTACK message to be
generated.
Receiver Port
For the SYN, SYNACK, and ACK messages, is what the
sender believes is the local port number for the link,
allocated by the entity at the far end of the link. If
the sender of the message does not know the port number
at the far end of the link, this field should be set to
zero. For the RSTACK message, the Receiver Port field is
set to the value of the Sender Port field from the
incoming message that caused the RSTACK message to be
generated.
Sender Instance
For the SYN, SYNACK, and ACK messages, is the sender's
instance number for the link. It is used to detect when
the link comes back up after going down or when the
identity of the entity at the other end of the link
changes. The instance number is a 32-bit number that is
guaranteed to be unique within the recent past and to
change when the link or node comes back up after going
down. Zero is not a valid instance number. For the
RSTACK message, the Sender Instance field is set to the
value of the Receiver Instance field from the incoming
message that caused the RSTACK message to be generated.
Receiver Instance
For the SYN, SYNACK, and ACK messages, is what the
sender believes is the current instance number for the
link, allocated by the entity at the far end of the
link. If the sender of the message does not know the
current instance number at the far end of the link, this
field should be set to zero. For the RSTACK message, the
Receiver Instance field is set to the value of the
Sender Instance field from the incoming message that
caused the RSTACK message to be generated.
10.2 Procedure
The adjacency protocol is described by the following rules and
state tables.
The rules and state tables use the following operations:
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o The "Update Peer Verifier" operation is defined as storing the
values of the Sender Instance, Sender Port, and Sender Name
fields from a SYN or SYNACK message received from the entity at
the far end of the link.
o The procedure "Reset the link" is defined as:
1. Generate a new instance number for the link
2. Delete the peer verifier (set to zero the values of
Sender Instance, Sender Port, and Sender Name previously
stored by the Update Peer Verifier operation)
3. Send a SYN message
4. Enter the SYNSENT state.
o The state tables use the following Boolean terms and operators:
A The Sender Instance in the incoming message matches the
value stored from a previous message by the "Update Peer
Verifier" operation.
B The Sender Instance, Sender Port, and Sender Name fields
in the incoming message match the values stored from a
previous message by the "Update Peer Verifier"
operation.
C The Receiver Instance, Receiver Port, and Receiver Name
fields in the incoming message match the values of the
Sender Instance, Sender Port, and Sender Name currently
sent in outgoing SYN, SYNACK, and ACK messages.
"&&" Represents the logical AND operation
"||" Represents the logical OR operation
"!" Represents the logical negation (NOT) operation.
o A timer is required for the periodic generation of SYN, SYNACK,
and ACK messages. The value of the timer is announced in the
Timer field. The period of the timer is unspecified but a value
of one second is suggested.
There are two independent events: the timer expires, and a
packet arrives. The processing rules for these events are:
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Timer Expires: Reset Timer
If state = SYNSENT Send SYN
If state = SYNRCVD Send SYNACK
If state = ESTAB Send ACK
Packet Arrives:
If incoming message is an RSTACK:
If (A && C && !SYNSENT) Reset the link
Else Discard the message.
If incoming message is a SYN, SYNACK, or ACK:
Response defined by the following State Tables.
If incoming message is any other GSMP message and
state != ESTAB:
Discard incoming message.
If state = SYNSENT Send SYN (Note 1)
If state = SYNRCVD Send SYNACK (Note 1)
Note 1: No more than two SYN or SYNACK messages should
be sent within any time period of length defined by
the timer.
o State synchronization across a link is considered to be
achieved when the protocol reaches the ESTAB state. All GSMP
messages, other than adjacency protocol messages, that are
received before synchronization is achieved will be discarded.
State Tables
State: SYNSENT
+======================================================================+
| Condition | Action | New State |
+====================+=====================================+===========+
| SYNACK && C | Update Peer Verifier; Send ACK | ESTAB |
+--------------------+-------------------------------------+-----------+
| SYNACK && !C | Send RSTACK | SYNSENT |
+--------------------+-------------------------------------+-----------+
| SYN | Update Peer Verifier; Send SYNACK | SYNRCVD |
+--------------------+-------------------------------------+-----------+
| ACK | Send RSTACK | SYNSENT |
+======================================================================+
State: SYNRCVD
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+======================================================================+
| Condition | Action | New State |
+====================+=====================================+===========+
| SYNACK && C | Update Peer Verifier; Send ACK | ESTAB |
+--------------------+-------------------------------------+-----------+
| SYNACK && !C | Send RSTACK | SYNRCVD |
+--------------------+-------------------------------------+-----------+
| SYN | Update Peer Verifier; Send SYNACK | SYNRCVD |
+--------------------+-------------------------------------+-----------+
| ACK && B && C | Send ACK | ESTAB |
+--------------------+-------------------------------------+-----------+
| ACK && !(B && C) | Send RSTACK | SYNRCVD |
+======================================================================+
State: ESTAB
+======================================================================+
| Condition | Action | New State |
+====================+=====================================+===========+
| SYN || SYNACK | Send ACK (note 2) | ESTAB |
+--------------------+-------------------------------------+-----------+
| ACK && B && C | Send ACK (note 3) | ESTAB |
+--------------------+-------------------------------------+-----------+
| ACK && !(B && C) | Send RSTACK | ESTAB |
+======================================================================+
Note 2: No more than two ACKs should be sent within any time
period of length defined by the timer. Thus, one ACK must be sent
every time the timer expires. In addition, one further ACK may be
sent between timer expirations if the incoming message is a SYN or
SYNACK. This additional ACK allows the adjacency protocol to reach
synchronization more quickly.
Note 3: No more than one ACK should be sent within any time period
of length defined by the timer.
10.3 Loss of Synchronization
If after synchronization is achieved, no valid GSMP messages are
received in any period of time in excess of three times the value
of the Timer field announced in the incoming adjacency protocol
messages, loss of synchronization may be declared.
The preferred procedure for a switch to use when it looses
synchronization with its active controller is to attempt to
establish synchronization with (one of) its backup controller(s).
However, in this preferred approach, it must not reset its state
until it achieves synchronization with a backup controller. This
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means that if, before achieving synchronization with a backup
controller, it regains synchronization with its original
controller, it may continue the original session (and cease
attempting to establish synchronization with a backup controller).
If synchronization with the original session is regained it is the
responsibility of the controller to ensure consistent state
between the switch and controller.
While the above is the preferred procedure, it is also the case
that the simplest procedure when declaring loss of synchronization
with the active controller is to reset the switch state, and start
searching for a controller. This simple procedure is legitimate.
11. Summary of Failure Response Codes
[Editor's note: this section is currently out of whack w.r.t. the
rest of the spec and will be updated in a future revision of the
draft.]
The following list gives a summary of the failure codes defined
for failure response messages:
1: Unspecified reason not covered by other failure codes.
2: Invalid request message.
3: The specified request is not implemented on this switch.
4: Invalid Port Session Number.
5: One or more of the specified ports does not exist.
6: One or more of the specified ports is down.
7: Unused. (This failure code has been replaced by failure
codes 18--21.)
8: The specified connection does not exist.
9: The specified branch does not exist.
10: A branch belonging to the specified point-to-multipoint
connection is already established on the specified
output port and the switch cannot support more than a
single branch of any point-to-multipoint connection on
the same output port.
11: The limit on the maximum number of point-to-multipoint
connections that the switch can support has been
reached.
12: The limit on the maximum number of branches that the
specified point-to-multipoint connection can support has
been reached.
13: Unable to assign the requested Label value to the
requested branch on the specified point-to-multipoint
connection.
14: General problem related to the manner in which point-to-
multipoint is supported by the switch.
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15: Out of resources (e.g. memory exhausted, etc.).
16: Failure specific to the particular message type. (The
meaning of this failure code depends upon the Message
Type. It is defined within the description of any
message that uses it.)
17: Cannot label each output branch of a point-to-multipoint
tree with a different label.
18: One or more of the specified input VPIs is invalid.
19: One or more of the specified input VCIs is invalid.
20: One or more of the specified output VPIs is invalid.
21: One or more of the specified output VCIs is invalid.
22: Invalid Class of Service field in a Connection Management
message.
23: Insufficient resources for QoS Profile.
24: Virtual path switching is not supported on this input
port.
25: Point-to-multipoint virtual path connections are not
supported on either the requested input port or the
requested output port.
26: Attempt to add a virtual path connection branch to an
existing virtual channel connection.
27: Attempt to add a virtual channel connection branch to an
existing virtual path connection.
28: Only point-to-point bidirectional connections may be
established.
29: Cannot support requested VPI range.
30: Cannot support requested VCI range on all requested VPIs.
31: The transmit cell rate of this output port cannot be
changed.
32: Requested transmit cell rate out of range for this output
port.
128: Weighted scheduling within this waiting room is
unavailable.
129: This waiting room is unable to offer weighted sharing for
a QoS class.
130: This waiting room is unable to offer weighted sharing for
a connection.
131: Scheduler Identifier still in use.
132: QoS Class Identifier still in use.
133: Invalid QoS parameter.
134: Insufficient QoS resources.
135: Any point-to-multipoint connection arriving on this input
port must use the same QoS parameters for all output
branches.
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12. Summary of Message Set
[Editor's note: this section is currently out of whack w.r.t. the
rest of the spec and will be updated in a future revision of the
draft.]
The following table gives a summary of the messages defined in
this version of the specification. It also indicates which
messages must be supported in a minimal implementation of the
protocol. Those messages marked as "Required" must be supported by
the switch for an implementation to be considered to conform to
this specification. (While the controller should also implement
those messages marked "Required," conformance cannot be tested for
the controller due to the Master-Slave nature of the protocol.)
Message Name Message Type Status
Connection Management Messages
Add Branch VCC....................16 Required
VPC....................26
Delete Tree.......................18
Delete All........................20
Delete Branches...................17 Required
Move Branch VCC...................22
VPC...................27
Port Management Messages
Port Management...................32 Required
Label Range.......................33
State and Statistics Messages
Connection Activity...............48
Port Statistics...................49 Required
Connection Statistics.............50
QoS Class Statistics..............51
Report Connection State...........52
Configuration Messages
Switch Configuration..............64 Required
Port Configuration................65 Required
All Ports Configuration...........66 Required
Event Messages
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Port Up...........................80
Port Down.........................81
Invalid Label...................82
New Port..........................83
Dead Port.........................84
Quality of Service Messages
QoS Configuration.................96
Scheduler Establishment...........97
QoS Class Establishment...........98
QoS Release.......................99
QoS Connection Management VCC....100
VPC....101
Adjacency Protocol....................10 Required
13. Security Considerations
Security considrations are not addressed in the current revision
of the draft.
References
[1] ATM Forum Traffic Management Specification 4.0, af-tm-
0056.000, April 1996.
[2] "B-ISDN ATM Layer Specification," International
Telecommunication Union, ITU-T Recommendation I.361, Mar.
1993.
[3] "B-ISDN ATM Adaptation Layer (AAL) Specification,"
International Telecommunication Union, ITU-T
Recommendation I.363, Mar. 1993.
[4] Ipsilon IP Switch MIB,
http://www.ipsilon.com/products/ips.mib.
[Editor's note: this reference is obsolete. The reference
must be removed if a suitable updated publication cannot
be found as a replacement.]
[5] Reynolds, J., and J. Postel, "Assigned Numbers," STD 2,
RFC 1700, October 1994.
[6] Newman, P, Edwards, W., Hinden, R., Hoffman, E. Ching
Liaw, F., Lyon, T. and Minshall, G., "Ipsilon's General
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Switch Management Protocol Specification," Version 1.1,
RFC 1987, August 1996.
[7] Newman, P, Edwards, W., Hinden, R., Hoffman, E., Ching
Liaw, F., Lyon, T. and Minshall, G., "Ipsilon's General
Switch Management Protocol Specification," Version 2.0,
RFC 2397, March 1998.
Authors' Addresses
Tom Worster
GDC
199 W Newton St
Boston MA 02116 USA
617 247 2624
tom.worster@gdc.com
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