Network Working Group J. Lang, Editor
Internet Draft Calient Networks
Category: Standards Track August 2002
Expires: February 2003
Link Management Protocol (LMP)
draft-ietf-ccamp-lmp-05.txt
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
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Abstract
For scalability purposes, multiple data links can be combined to
form a single traffic engineering (TE) link. Furthermore, the
management of TE links is not restricted to in-band messaging, but
instead can be done using out-of-band techniques. This document
specifies a link management protocol (LMP) that runs between
neighboring nodes and is used to manage TE links. Specifically, LMP
will be used to maintain control channel connectivity, verify the
physical connectivity of the data links, correlate the link property
information, suppress downstream alarms, and localize link failures
for protection/restoration purposes in multiple kinds of networks.
J. Lang, Editor Standards Track [Page 1]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
Table of Contents
1 Introduction ................................................ 5
1.1 Terminology ............................................. 5
2 LMP Overview ................................................ 8
3 Control Channel Management .................................. 10
3.1 Parameter Negotiation ................................... 11
3.2 Hello Protocol .......................................... 12
3.2.1 Hello Parameter Negotiation ...................... 12
3.2.2 Fast Keep-alive .................................. 13
3.2.3 Control Channel Down ............................. 13
3.2.4 Degraded State ................................... 14
4 Link Property Correlation ................................... 14
5 Verifying Link Connectivity ................................. 16
5.1 Example of Link Connectivity Verification ............... 18
6 Fault Management ............................................ 20
6.1 Fault Detection ......................................... 20
6.2 Fault Localization Procedure ............................ 20
6.3 Examples of Fault Localization .......................... 21
6.4 Channel Activation Indication ........................... 22
6.5 Channel Deactivation Indication ......................... 22
7 Message_Id Usage ............................................ 23
8 Graceful Restart ............................................ 24
9 Addressing .................................................. 25
10 Exponential Back-off Procedures ............................. 25
10.1 Operation............................................... 25
10.2 Retransmission Algorithm ............................... 26
11 LMP Finite State Machines ................................... 27
11.1 Control Channel FSM .................................... 27
11.1.1 Control Channel States .......................... 27
11.1.2 Control Channel Events .......................... 28
11.1.3 Control Channel FSM Description ................. 30
11.2 TE Link FSM ............................................ 31
11.2.1 TE Link States .................................. 31
11.2.2 TE Link Events .................................. 31
11.2.3 TE Link FSM Description ......................... 32
11.3 Data Link FSM .......................................... 32
11.3.1 Data Link States ................................ 33
11.3.2 Data Link Events ................................ 33
11.3.3 Active Data Link FSM Description ................ 35
11.3.4 Passive Data Link FSM Description ............... 36
12 LMP Message Formats ......................................... 37
12.1 Common Header .......................................... 37
12.2 LMP Object Format ...................................... 38
12.3 Parameter Negotiation Messages ......................... 39
12.4 Hello Message .......................................... 41
12.5 Link Verification Messages ............................. 41
12.6 Link Summary Messages .................................. 45
12.7 Fault Management Messages .............................. 46
13 LMP Object Definitions ...................................... 47
14 Intellectual Property Considerations ........................ 65
15 References .................................................. 65
16 Security Considerations ..................................... 66
J. Lang, Editor Standards Track [Page 2]
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16.1 Security Requirements .................................. 66
16.2 Security Mechanisms .................................... 67
17 IANA Considerations ......................................... 68
18 Acknowledgements ............................................ 71
19 Contributors ................................................ 72
20 Contact Address ............................................. 72
21 Full Copyright Statement .................................... 73
J. Lang, Editor Standards Track [Page 3]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
[Editor's note: ææChanges from previous versionÆÆ notes can be removed
prior to publication as an RFC.]
Changes from previous version:
o Editorial changes.
o Added a terminology section
o Added text to the Security Considerations section.
o Removed discussion of the BeginVerifyTransport flags for specific
Encoding Types to a separate Internet Draft.
o Added a terminology section.
o Removed the LMP checksum.
o Clarified the IANA Considerations section with assignment rules
and suggested values.
J. Lang, Editor Standards Track [Page 4]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
1. Introduction
Networks are being developed with routers, switches, crossconnects,
DWDM systems, and add-drop multiplexors (ADMs) that use a common
control plane [e.g., Generalized MPLS (GMPLS)] to dynamically
allocate resources and to provide network survivability using
protection and restoration techniques. A pair of nodes may have
thousands of interconnects, where each interconnect may consist of
multiple data links when multiplexing (e.g., Frame Relay DLCIs at
Layer 2, or TDM slots or WDM wavelengths at Layer 1) is used. For
scalability purposes, multiple data links may be combined into a
single traffic-engineering (TE) link.
To enable communication between nodes for routing, signaling, and
link management, there must be a pair of IP interfaces that are
mutually reachable. We call such a pair of interfaces a control
channel. Note that "mutually reachable" does not imply that these
two interfaces are (directly) connected by an IP link; there may be
an IP network between the two. Furthermore, the interface over
which the control messages are sent/received may not be the same
interface over which the data flows. This document specifies a link
management protocol (LMP) that runs between neighboring nodes and is
used to manage TE links and verify reachability of the control
channel.
In GMPLS, the control channels between two adjacent nodes are no
longer required to use the same physical medium as the data links
between those nodes. For example, a control channel could use a
separate virtual circuit, wavelength, fiber, Ethernet link, an IP
tunnel routed over a separate management network, or a multi-hop IP
network. A consequence of allowing the control channel(s) between
two nodes to be logically or physically diverse from the associated
data links is that the health of a control channel does not
necessarily correlate to the health of the data links, and vice-
versa. Therefore, a clean separation between the fate of the
control channel and data links must be made. New mechanisms must be
developed to manage the data links, both in terms of link
provisioning and fault management.
Among the tasks that LMP accomplishes is checking that the grouping
of links into TE links as well as the properties of those links are
the same at both end points of the links -- this is called "link
property correlation". Also, LMP can communicate these link
properties to the IGP module, which can then announce them to other
nodes in the network. LMP can also tell the signaling module the
mapping between TE links and control channels. Thus, LMP performs a
valuable "glue" function in the control plane.
Note that while the existence of the control network (single or
multi-hop) is necessary for enabling communication, it is by no
means sufficient. For example, if the two interfaces are separated
by an IP network, faults in the IP network may result in the lack of
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an IP path from one interface to another, and therefore in an
interruption of communication between the two interfaces. On the
other hand, not every failure in the control network affects a given
control channel, hence the need for establishing and managing
control channels.
For the purposes of this document, a data link may be considered by
each node that it terminates on as either a 'port' or a 'component
link' depending on the multiplexing capability of the endpoint on
that link; component links are multiplex capable, whereas ports are
not multiplex capable. This distinction is important since the
management of such links (including, for example, resource
allocation, label assignment, and their physical verification) is
different based on their multiplexing capability. For example, a
Frame Relay switch is able to demultiplex an interface into virtual
circuits based on DLCIs; similarly, a SONET crossconnect with OC-192
interfaces may be able to demultiplex the OC-192 stream into four
OC-48 streams. If multiple interfaces are grouped together into a
single TE link using link bundling [BUNDLE], then the link resources
must be identified using three levels: Link_Id, component interface
Id, and label identifying virtual circuit, timeslot, etc. Resource
allocation happens at the lowest level (labels), but physical
connectivity happens at the component link level. As another
example, consider the case where an optical switch (e.g., PXC)
transparently switches OC-192 lightpaths. If multiple interfaces
are once again grouped together into a single TE link, then link
bundling [BUNDLE] is not required and only two levels of
identification are required: Link_Id and Port_Id. In this case,
both resource allocation and physical connectivity happen at the
lowest level (i.e. port level).
To ensure interworking between data links with different
multiplexing capabilities, LMP capable devices SHOULD allow sub-
channels of a component link to be locally configured as (logical)
data links. For example, if a Router with 4 OC-48 interfaces is
connected through a 4:1 MUX to an OXC with OC-192c interfaces, the
OXC SHOULD be able to configure each OC-48 sub-channel as a data
link.
LMP is designed to support aggregation of one or more data links
into a TE link (either ports into TE links, or component links into
TE links). The purpose of forming a TE link is to group/map the
information about certain physical resources (and their properties)
into the information that is used by Constrained SPF for the purpose
of path computation, and by GMPLS signaling.
1.1. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
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The reader is assumed to be familiar with the terminology in [GMPLS-
SIG], [GMPLS-RTG], and [BUNDLE].
Bundled Link:
As defined in [BUNDLE], a bundled link is a TE link such that for
the purpose of GMPLS signaling a combination of <link identifier,
label> is not sufficient to unambiguously identify the
appropriate resources used by an LSP. A bundled link is composed
of two or more component links.
Control Channel:
A control channel is a pair of mutually reachable interfaces that
are used to enable communication between nodes for routing,
signaling, and link management.
Component Link:
As defined in [BUNDLE], a component link is a subset of resources
of a TE Link such that (a) the partition is minimal, and (b)
within each subset a label is sufficient to unambiguously
identify the appropriate resources used by an LSP.
Data Link:
A data link is a pair of interfaces that are used to transfer
user data. Note that in GMPLS, the control channel(s) between
two adjacent nodes are no longer required to use the same
physical medium as the data links between those nodes.
Link Property Correlation:
This is a procedure to correlate the local and remote properties
of a TE link.
Multiplex Capability:
The ability to multiplex/demultiplex a data stream into sub-rate
streams for switching purposes.
Port:
An interface that terminates a data link.
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TE Link:
As defined in [GMPLS-RTG], a TE link is a logical construct that
represents a way to group/map the information about certain
physical resources (and their properties) that interconnect LSRs
into the information that is used by Constrained SPF for the
purpose of path computation, and by GMPLS signaling.
Transparent:
A device is called X-transparent if it forwards incoming signals
from input to output without examining or modifying the X aspect
of the signal. For example, a Frame Relay switch is network-
layer transparent; an all-optical switch is electrically
transparent.
2. LMP Overview
The two core procedures of LMP are control channel management and
link property correlation. Control channel management is used to
establish and maintain control channels between adjacent nodes.
This is done using a Config message exchange and a fast keep-alive
mechanism between the nodes. The latter is required if lower-level
mechanisms are not available to detect control channel failures.
Link property correlation is used to synchronize the TE link
properties and verify the TE link configuration.
LMP requires that a pair of nodes have at least one active bi-
directional control channel between them. Each direction of the
control channel is identified by a Control Channel Id (CC_Id), and
the two directions are coupled together using the LMP Config message
exchange. All LMP packets are run over UDP with an LMP port number
[except in some cases, the Test Message which may be limited by the
transport mechanism for in-band messaging]. The link level encoding
of the control channel is outside the scope of this document.
An "LMP adjacency" is formed between two nodes when at least one bi-
directional control channel is established between them. Multiple
control channels may be active simultaneously for each adjacency;
control channel parameters, however, MUST be individually negotiated
for each control channel. If the LMP fast keep-alive is used over a
control channel, LMP Hello messages MUST be exchanged over the
control channel. Other LMP messages MAY be transmitted over any of
the active control channels between a pair of adjacent nodes. One
or more active control channels may be grouped into a logical
control channel for signaling, routing, and link property
correlation purposes.
The link property correlation function of LMP is designed to
aggregate multiple data links (ports or component links) into a TE
link and to synchronize the properties of the TE link. As part of
the link property correlation function, a LinkSummary message
exchange is defined. The LinkSummary message includes the local and
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remote Link_Ids, a list of all data links that comprise the TE link,
and various link properties. A LinkSummaryAck or LinkSummaryNack
message MUST be sent in response to the receipt of a LinkSummary
message indicating agreement or disagreement on the link properties.
LMP messages are transmitted reliably using Message_Ids and
retransmissions. Message_Ids are carried in MESSAGE_ID objects. No
more than one MESSAGE_ID object may be included in an LMP message.
For control channel specific messages, the Message_Id is within the
scope of the control channel over which the message is sent. For TE
link specific messages, the Message_Id is within the scope of the
LMP adjacency. The value of the Message_Id is monotonically
increasing and only decreases when the value wraps.
In this document, two additional LMP procedures are defined: link
connectivity verification and fault management. These procedures
are particularly useful when the control channels are physically
diverse from the data links. Link connectivity verification is used
for data plane discovery, Interface_Id exchange (Interface_Ids are
used in GMPLS signaling, either as port labels or component link
identifiers, depending on the configuration), and physical
connectivity verification. This is done by sending Test messages
over the data links and TestStatus messages back over the control
channel. Note that the Test message is the only LMP message that
must be transmitted over the data link. The ChannelStatus message
exchange is used between adjacent nodes for both the suppression of
downstream alarms and the localization of faults for protection and
restoration.
For LMP link connectivity verification, the Test message is
transmitted over the data links. For X-transparent devices, this
requires examining and modifying the X aspect of the signal. The
LMP link connectivity verification procedure is coordinated using a
BeginVerify message exchange over a control channel. To support
various aspects of transparency, a Verify Transport Mechanism is
included in the BeginVerify and BeginVerifyAck messages. Note that
there is no requirement that all data links must lose their
transparency simultaneously, but at a minimum, it must be possible
to terminate them one at a time. There is also no requirement that
the control channel and TE link use the same physical medium;
however, the control channel MUST terminate on the same two nodes
that the TE link spans. Since the BeginVerify message exchange
coordinates the Test procedure, it also naturally coordinates the
transition of the data links in and out of the transparent mode.
The LMP fault management procedure is based on a ChannelStatus
message exchange using the following messages: ChannelStatus,
ChannelStatusAck, ChannelStatusRequest, and ChannelStatusResponse.
The ChannelStatus message is sent unsolicited and is used to notify
an LMP neighbor about the status of one or more data channels of a
TE link. The ChannelStatusAck message is used to acknowledge
receipt of the ChannelStatus message. The ChannelStatusRequest
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message is used to query an LMP neighbor for the status of one or
more data channels of a TE Link. The ChannelStatusResponse message
is used to acknowledge receipt of the ChannelStatusRequest message
and indicate the states of the queried data links.
3. Control Channel Management
To initiate an LMP adjacency between two nodes, one or more bi-
directional control channels MUST be activated. The control
channels can be used to exchange control-plane information such as
link provisioning and fault management information (implemented
using a messaging protocol such as LMP, proposed in this document),
path management and label distribution information (implemented
using a signaling protocol such as RSVP-TE [RFC3209]), and network
topology and state distribution information (implemented using
traffic engineering extensions of protocols such as OSPF [OSPF-TE]
and IS-IS [ISIS-TE]).
For the purposes of LMP, the exact implementation of the control
channel is not specified; it could be, for example, a separate
wavelength or fiber, an Ethernet link, an IP tunnel through a
separate management network, or the overhead bytes of a data link.
Rather, a node-wide unique 32-bit non-zero integer control channel
identifier (CC_Id) is assigned at each end of the control channel.
This identifier comes from the same space as the unnumbered
interface Id. Furthermore, LMP packets are run over UDP with an LMP
port number. Thus, the link level encoding of the control channel
is not part of the LMP specification.
To establish a control channel, the destination IP address on the
far end of the control channel must be known. This knowledge may be
manually configured or automatically discovered. Note that for in-
band signaling, a control channel could be explicitly configured on
a particular data link. In this case, the Config message exchange
can be used to dynamically learn the IP address on the far end of
the control channel. This is done by sending the Config message to
the Multicast address (224.0.0.1). The ConfigAck and ConfigNack
messages MUST be sent to the source IP address found in the IP
header of the received Config message.
Control channels exist independently of TE links and multiple
control channels may be active simultaneously between a pair of
nodes. Individual control channels can be realized in different
ways; one might be implemented in-fiber while another one may be
implemented out-of-fiber. As such, control channel parameters MUST
be negotiated over each individual control channel, and LMP Hello
packets MUST be exchanged over each control channel to maintain LMP
connectivity if other mechanisms are not available. Since control
channels are electrically terminated at each node, it may be
possible to detect control channel failures using lower layers
(e.g., SONET/SDH).
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There are four LMP messages that are used to manage individual
control channels. They are the Config, ConfigAck, ConfigNack, and
Hello messages. These messages MUST be transmitted on the channel
to which they refer. All other LMP messages may be transmitted over
any of the active control channels between a pair of LMP adjacent
nodes.
In order to maintain an LMP adjacency, it is necessary to have at
least one active control channel between a pair of adjacent nodes
(recall that multiple control channels can be active simultaneously
between a pair of nodes). In the event of a control channel
failure, alternate active control channels can be used and it may be
possible to activate additional control channels as described below.
3.1. Parameter Negotiation
Control channel activation begins with a parameter negotiation
exchange using Config, ConfigAck, and ConfigNack messages. The
contents of these messages are built using LMP objects, which can be
either negotiable or non-negotiable (identified by the N bit in the
object header). Negotiable objects can be used to let LMP peers
agree on certain values. Non-negotiable objects are used for the
announcement of specific values that do not need, or do not allow,
negotiation.
To activate a control channel, a Config message MUST be transmitted
to the remote node, and in response, a ConfigAck message MUST be
received at the local node. The Config message contains the Local
Control Channel Id (CC_Id), the sender's Node_Id, a Message_Id for
reliable messaging, and a CONFIG object. It is possible that both
the local and remote nodes initiate the configuration procedure at
the same time. To avoid ambiguities, the node with the higher
Node_Id wins the contention; the node with the lower Node_Id MUST
stop transmitting the Config message and respond to the Config
message it received.
The ConfigAck message is used to acknowledge receipt of the Config
message and express agreement on ALL of the configured parameters
(both negotiable and non-negotiable).
The ConfigNack message is used to acknowledge receipt of the Config
message, indicate which (if any) non-negotiable CONFIG objects are
unacceptable, and propose alternate values for the negotiable
parameters.
If a node receives a ConfigNack message with acceptable alternate
values for negotiable parameters, the node SHOULD transmit a Config
message using these values for those parameters.
If a node receives a ConfigNack message with unacceptable alternate
values, the node MAY continue to retransmit Config messages. Note
that the problem may be solved by an operator changing parameters.
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In the case where multiple control channels use the same physical
interface, the parameter negotiation exchange is performed for each
control channel. The various LMP parameter negotiation messages are
associated with their corresponding control channels by their node-
wide unique identifiers (CC_Ids).
3.2. Hello Protocol
Once a control channel is activated between two adjacent nodes, the
LMP Hello protocol can be used to maintain control channel
connectivity between the nodes and to detect control channel
failures. The LMP Hello protocol is intended to be a lightweight
keep-alive mechanism that will react to control channel failures
rapidly so that IGP Hellos are not lost and the associated link-
state adjacencies are not removed unnecessarily.
3.2.1. Hello Parameter Negotiation
Before sending Hello messages, the HelloInterval and
HelloDeadInterval parameters MUST be agreed upon by the local and
remote nodes. These parameters are exchanged in the Config message.
The HelloInterval indicates how frequently LMP Hello messages will
be sent, and is measured in milliseconds (ms). For example, if the
value were 150, then the transmitting node would send the Hello
message at least every 150ms. The HelloDeadInterval indicates how
long a device should wait to receive a Hello message before
declaring a control channel dead, and is measured in milliseconds
(ms).
The HelloDeadInterval MUST be greater than the HelloInterval, and
SHOULD be at least 3 times the value of HelloInterval. If the fast
keep-alive mechanism of LMP is not used, the HelloInterval and
HelloDeadInterval parameters MUST be set to zero.
Suggested default values for the HelloInterval is 5 ms and for the
HelloDeadInterval is 18 ms.
When a node has either sent or received a ConfigAck message, it may
begin sending Hello messages. Once it has sent a Hello message and
received a valid Hello message (i.e., with expected sequence
numbers; see Section 3.2.2), the control channel moves to the up
state. (It is also possible to move to the up state without sending
Hellos if other methods are used to indicate bi-directional control-
channel connectivity.) If, however, a node receives a ConfigNack
message instead of a ConfigAck message, the node MUST not send Hello
messages and the control channel SHOULD NOT move to the up state.
See Section 11.1 for the complete control channel FSM.
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3.2.2. Fast Keep-alive
Each Hello message contains two sequence numbers: the first sequence
number (TxSeqNum) is the sequence number for the Hello message being
sent and the second sequence number (RcvSeqNum) is the sequence
number of the last Hello message received from the adjacent node
over this control channel.
There are two special sequence numbers. TxSeqNum MUST NOT ever be
0. TxSeqNum = 1 is used to indicate that the sender has just
started or has restarted and has no recollection of the last
TxSeqNum that was sent. Thus, the first Hello sent has a TxSeqNum
of 1 and an RxSeqNum of 0. When TxSeqNum reaches 2^32 -1, the next
sequence number used is 2, not 0 or 1, as these have special
meanings.
Under normal operation, the difference between the RcvSeqNum in a
Hello message that is received and the local TxSeqNum that is
generated will be at most 1. This difference can be more than one
only when a control channel restarts or when the values wrap.
Since the 32-bit sequence numbers may wrap, the following expression
may be used to test if a newly received TxSeqNum value is less than
a previously received value:
If ((int) old_id - (int) new_id > 0) {
New value is less than old value;
}
Having sequence numbers in the Hello messages allows each node to
verify that its peer is receiving its Hello messages. By including
the RcvSeqNum in Hello packets, the local node will know which Hello
packets the remote node has received.
The following example illustrates how the sequence numbers operate.
Note that only the operation at one node is shown, and alternative
scenarios are possible:
1) After completing the configuration stage, Node A sends Hello
messages to Node B with {TxSeqNum=1;RcvSeqNum=0}.
2) When Node A receives a Hello from Node B with
{TxSeqNum=1;RcvSeqNum=1}, it sends Hellos to Node B with
{TxSeqNum=2;RcvSeqNum=1}.
3) When Node A receives a Hello from Node B with
{TxSeqNum=2;RcvSeqNum=2}, it sends Hellos to Node B with
{TxSeqNum=3;RcvSeqNum=2}.
3.2.3. Control Channel Down
To allow bringing a control channel down gracefully for
administration purposes, a ControlChannelDown flag is available in
the Common Header of LMP packets. When data links are still in use
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between a pair of nodes, a control channel SHOULD only be taken down
administratively when there are other active control channels that
can be used to manage the data links.
When bringing a control channel down administratively, a node MUST
set the ControlChannelDown flag in all LMP messages sent over the
control channel. The node that initiated the control channel down
procedure may stop sending Hello messages after HelloDeadInterval
seconds have passed, or if it receives an LMP message over the same
control channel with the ControlChannelDown flag set.
When a node receives an LMP packet with the ControlChannelDown flag
set, it SHOULD send a Hello message with the ControlChannelDown flag
set and move the control channel to the down state.
3.2.4. Degraded State
A consequence of allowing the control channels to be physically
diverse from the associated data links is that there may not be any
active control channels available while the data links are still in
use. For many applications, it is unacceptable to tear down a link
that is carrying user traffic simply because the control channel is
no longer available; however, the traffic that is using the data
links may no longer be guaranteed the same level of service. Hence
the TE link is in a Degraded state.
When a TE link is in the Degraded state, routing and signaling
SHOULD be notified so that new connections are not accepted and the
TE link is advertised with no unreserved resources.
4. Link Property Correlation
As part of LMP, a link property correlation exchange is defined for
TE links using the LinkSummary, LinkSummaryAck, and LinkSummaryNack
messages. The contents of these messages are built using LMP
objects, which can be either negotiable or non-negotiable
(identified by the N flag in the object header). Negotiable objects
can be used to let both sides agree on certain link parameters.
Non-negotiable objects are used for announcement of specific values
that do not need, or do not allow, negotiation.
Each TE link has an identifier (Link_Id) that is assigned at each
end of the link. These identifiers MUST be the same type (i.e,
IPv4, IPv6, unnumbered) at both ends. If a LinkSummary message is
received with different local and remote TE link types, then a
LinkSummaryNack message MUST be sent with Error Code "Bad TE Link
Object". Similarly, each data link is assigned an identifier
(Interface_Id) at each end. These identifiers MUST also be the same
type at both ends. If a LinkSummary message is received with
different local and remote Interface_Id types then a LinkSummaryNack
message MUST be sent with Error Code "Bad Data Link Object".
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Link property correlation SHOULD be done before the link is brought
up and MAY be done at any time a link is up and not in the
Verification process.
The LinkSummary message is used to verify for consistency the TE and
data link information on both sides. Link Summary messages are also
used to aggregate multiple data links (either ports or component
links) into a TE link; exchange, correlate (to determine
inconsistencies), or change TE link parameters; and exchange,
correlate (to determine inconsistencies), or change Interface_Ids
(used either Port_Ids or component link identifiers).
The LinkSummary message includes a TE_LINK object followed by one or
more DATA_LINK objects. The TE_LINK object identifies the TE link's
local and remote Link_Id and indicates support for fault management
and link verification procedures for that TE link. The DATA_LINK
objects are used to characterize the data links that comprise the TE
link. These objects include the local and remote Interface_Ids, and
may include one or more sub-objects further describing the
properties of the data links.
If the LinkSummary message is received from a remote node and the
Interface_Id mappings match those that are stored locally, then the
two nodes have agreement on the Verification procedure (see Section
5) and data link identification configuration. If the verification
procedure is not used, the LinkSummary message can be used to verify
agreement on manual configuration.
The LinkSummaryAck message is used to signal agreement on the
Interface_Id mappings and link property definitions. Otherwise, a
LinkSummaryNack message MUST be transmitted, indicating which
Interface mappings are not correct and/or which link properties are
not accepted. If a LinkSummaryNack message indicates that the
Interface_Id mappings are not correct and the link verification
procedure is enabled, the link verification process SHOULD be
repeated for all mismatched free data links; if an allocated data
link has a mapping mismatch, it SHOULD be flagged and verified when
it becomes free. If a LinkSummaryNack message includes negotiable
parameters, then acceptable values for those parameters MUST be
included. If a LinkSummaryNack message is received and includes
negotiable parameters, then the initiator of the LinkSummary message
SHOULD send a new LinkSummary message. The new LinkSummary message
SHOULD include new values for the negotiable parameters. These
values SHOULD take into account the acceptable values received in
the LinkSummaryNack message.
It is possible that the LinkSummary message could grow quite large
due to the number of DATA LINK objects. An LMP implementation
SHOULD be able to fragment when transmitting LMP messages, and MUST
be able to re-assemble IP fragments when receiving LMP messages.
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5. Verifying Link Connectivity
In this section, an optional procedure is described that may be used
to verify the physical connectivity of the data links and
dynamically learn (i.e., discover) the TE link and Interface_Id
associations. The procedure SHOULD be done when establishing a TE
link, and subsequently, on a periodic basis for all unallocated
(free) data links of the TE link.
Support for this procedure is indicated by setting the "Link
Verification Supported" flag in the TE_LINK object of the
LinkSummary message.
If a BeginVerify message is received and link verification is not
supported for the TE link, then a BeginVerifyNack message MUST be
transmitted with Error Code indicating, "Link Verification Procedure
not supported for this TE Link."
A unique characteristic of transparent devices is that the data is
not modified or examined in normal operation. This characteristic
poses a challenge for validating the connectivity of the data links
and establish the label mappings. Therefore, to ensure proper
verification of data link connectivity, it is required that until
the data links are allocated for user traffic, they must be opaque
(i.e., lose their transparency). To support various degrees of
opaqueness (e.g., examining overhead bytes, terminating the IP
payload, etc.), and hence different mechanisms to transport the Test
messages, a Verify Transport Mechanism field is included in the
BeginVerify and BeginVerifyAck messages.
There is no requirement that all data links be terminated
simultaneously, but at a minimum, the data links MUST be able to be
terminated one at a time. Furthermore, for the link verification
procedure it is assumed that the nodal architecture is designed so
that messages can be sent and received over any data link. Note
that this requirement is trivial for opaque devices since each data
link is electrically terminated and processed before being forwarded
to the next opaque device, but that in transparent devices this is
an additional requirement.
To interconnect two nodes, a TE link is defined between them, and at
a minimum, there MUST be at least one active control channel between
the nodes. For link verification, a TE link MUST include at least
one data link.
Once a control channel has been established between the two nodes,
data link connectivity can be verified by exchanging Test messages
over each of the data links specified in the TE link. It should be
noted that all LMP messages except the Test message are exchanged
over the control channels and that Hello messages continue to be
exchanged over each control channel during the data link
verification process. The Test message is sent over the data link
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that is being verified. Data links are tested in the transmit
direction as they are unidirectional, and therefore, it may be
possible for both nodes to (independently) exchange the Test
messages simultaneously.
To initiate the link verification procedure, the local node MUST
send a BeginVerify message over a control channel. To limit the
scope of Link Verification to a particular TE Link, the local
Link_Id MUST be non-zero. If this field is zero, the data links can
span multiple TE links and/or they may comprise a TE link that is
yet to be configured. For the case where the local Link_Id field is
zero, the "Verify all Links" flag of the BEGIN_VERIFY object is used
to distinguish between data links that span multiple TE links and
those that have not yet been assigned to a TE link. Specifically,
verification of data links that span multiple TE links is indicated
by setting the local Link_Id field to zero and setting the "Verify
all Links" flag. Verification of data links that have not yet been
assigned to a TE link is indicated by setting the local Link_Id
field to zero and clearing the "Verify all Links" flag.
The BeginVerify message also contains the number of data links that
are to be verified; the interval (called VerifyInterval) at which
the Test messages will be sent; the encoding scheme and transport
mechanisms that are supported; the data rate for Test messages; and,
when the data links correspond to fibers, the wavelength identifier
over which the Test messages will be transmitted.
If the remote node receives a BeginVerify message and it is ready to
process Test messages, it MUST send a BeginVerifyAck message back to
the local node specifying the desired transport mechanism for the
TEST messages. The remote node includes a 32-bit node unique
Verify_Id in the BeginVerifyAck message. The Verify_Id is then used
in all corresponding verification messages to differentiate them
from different LMP peers and/or parallel Test procedures. When the
local node receives a BeginVerifyAck message from the remote node,
it may begin testing the data links by transmitting periodic Test
messages over each data link. The Test message includes the
Verify_Id and the local Interface_Id for the associated data link.
The remote node MUST send either a TestStatusSuccess or a
TestStatusFailure message in response for each data link. A
TestStatusAck message MUST be sent to confirm receipt of the
TestStatusSuccess and TestStatusFailure messages.
It is also permissible for the sender to terminate the Test
procedure anytime after sending the BeginVerify message. An
EndVerify message SHOULD be sent for this purpose.
Message correlation is done using message identifiers and the
Verify_Id; this enables verification of data links, belonging to
different link bundles or LMP sessions, in parallel.
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When the Test message is received, the received Interface_Id (used
in GMPLS as either a Port label or component link identifier
depending on the configuration) is recorded and mapped to the local
Interface_Id for that data link, and a TestStatusSuccess message
MUST be sent. The TestStatusSuccess message includes the local
Interface_Id along with the Interface_Id and Verify_Id received in
the Test message. The receipt of a TestStatusSuccess message
indicates that the Test message was detected at the remote node and
the physical connectivity of the data link has been verified. When
the TestStatusSuccess message is received, the local node SHOULD
mark the data link as up and send a TestStatusAck message to the
remote node. If, however, the Test message is not detected at the
remote node within an observation period (specified by the
VerifyDeadInterval), the remote node MUST send a TestStatusFailure
message over the control channel indicating that the verification of
the physical connectivity of the data link has failed. When the
local node receives a TestStatusFailure message, it SHOULD mark the
data link as FAILED and send a TestStatusAck message to the remote
node. When all the data links on the list have been tested, the
local node SHOULD send an EndVerify message to indicate that testing
is complete on this link.
If the local/remote data link mappings are known, then the link
verification procedure can be optimized by testing the data links in
a defined order known to both nodes. The suggested criterion for
this ordering is in increasing value of the remote Interface_Id.
Both the local and remote nodes SHOULD maintain the complete list of
Interface_Id mappings for correlation purposes.
5.1. Example of Link Connectivity Verification
Figure 1 shows an example of the link verification scenario that is
executed when a link between Node A and Node B is added. In this
example, the TE link consists of three free ports (each transmitted
along a separate fiber) and is associated with a bi-directional
control channel (indicated by a "c"). The verification process is
as follows:
o A sends a BeginVerify message over the control channel to B
indicating it will begin verifying the ports that form the TE
link. The LOCAL_LINK_ID object carried in the BeginVerify
message carries the identifier (IP address or interface index)
that A assigns to the link.
o Upon receipt of the BeginVerify message, B creates a Verify_Id
and binds it to the TE Link from A. This binding is used later
when B receives the Test messages from A, and these messages
carry the Verify_Id. B discovers the identifier (IP address or
interface index) that A assigns to the TE link by examining the
LOCAL_LINK_ID object carried in the received BeginVerify
message. (If the data ports are not yet assigned to the TE
Link, the binding is limited to the Node_Id of A.) In response
to the BeginVerify message, B sends to A the BeginVerifyAck
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message. The LOCAL_LINK_ID object carried in the
BeginVerifyAck message is used to carry the identifier (IP
address or interface index) that B assigns to the TE link. The
REMOTE_LINK_ID object carried in the BeginVerifyAck message is
used to bind the Link_Ids assigned by both A and B. The
Verify_Id is returned to A in the BeginVerifyAck message over
the control channel.
o When A receives the BeginVerifyAck message, it begins
transmitting periodic Test messages over the first port
(Interface Id=1). The Test message includes the Interface_Id
for the port and the Verify_Id that was assigned by B.
o When B receives the Test messages, it maps the received
Interface_Id to its own local Interface_Id = 10 and transmits a
TestStatusSuccess message over the control channel back to Node
A. The TestStatusSuccess message includes both the local and
received Interface_Ids for the port as well as the Verify_Id.
The Verify_Id is used to determine the local/remote TE link
identifiers (IP addresses or interface indices) for which the
data links belong.
o A will send a TestStatusAck message over the control channel
back to B indicating it received the TestStatusSuccess message.
o The process is repeated until all of the ports are verified.
o At this point, A will send an EndVerify message over the
control channel to B to indicate that testing is complete.
o B will respond by sending an EndVerifyAck message over the
control channel back to A.
Note that this procedure can be used to "discover" the
connectivity of the data ports.
+---------------------+ +---------------------+
+ + + +
+ Node A +<-------- c --------->+ Node B +
+ + + +
+ + + +
+ 1 +--------------------->+ 10 +
+ + + +
+ + + +
+ 2 + /---->+ 11 +
+ + /----/ + +
+ + /---/ + +
+ 3 +----/ + 12 +
+ + + +
+ + + +
+ 4 +--------------------->+ 14 +
+ + + +
+---------------------+ +---------------------+
Figure 1: Example of link connectivity between Node A and Node B.
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6. Fault Management
In this section, an optional LMP procedure is described that is used
to manage failures by rapid notification of the status of one or
more data channels of a TE Link. The scope of this procedure is
within a TE link, and as such, the use of this procedure is
negotiated as part of the LinkSummary exchange. The procedure can
be used to rapidly isolate link failures and is designed to work for
both unidirectional and bi-directional LSPs.
An important implication of using transparent devices is that
traditional methods that are used to monitor the health of allocated
data links in may no longer be appropriate. Instead, fault
detection is delegated to the physical layer (i.e., loss of light or
optical monitoring of the data) instead of layer 2 or layer 3.
Recall that a TE link connecting two nodes may consist of a number
of data links. If one or more data links fail between two nodes, a
mechanism must be used for rapid failure notification so that
appropriate protection/restoration mechanisms can be initiated. If
the failure is subsequently cleared, then a mechanism must be used
to notify that the failure is clear and the channel status is OK.
6.1. Fault Detection
Fault detection should be handled at the layer closest to the
failure; for optical networks, this is the physical (optical) layer.
One measure of fault detection at the physical layer is detecting
loss of light (LOL). Other techniques for monitoring optical
signals are still being developed and will not be further considered
in this document. However, it should be clear that the mechanism
used for fault notification in LMP is independent of the mechanism
used to detect the failure, but simply relies on the fact that a
failure is detected.
6.2. Fault Localization Procedure
In some situations, a data link failure between two nodes is
propagated downstream such that all the downstream nodes detect the
failure without localizing the failure. To avoid multiple alarms
stemming from the same failure, LMP provides failure notification
through the ChannelStatus message. This message may be used to
indicate that a single data channel has failed, multiple data
channels have failed, or an entire TE link has failed. Failure
correlation is done locally at each node upon receipt of the failure
notification.
To localize a fault to a particular link between adjacent nodes, a
downstream node (downstream in terms of data flow) that detects data
link failures will send a ChannelStatus message to its upstream
neighbor indicating that a failure has been detected (bundling
together the notification of all of the failed data links). An
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upstream node that receives the ChannelStatus message MUST send a
ChannelStatusAck message to the downstream node indicating it has
received the ChannelStatus message. The upstream node should
correlate the failure to see if the failure is also detected locally
for the corresponding LSP(s). If, for example, the failure is clear
on the input of the upstream node or internally, then the upstream
node will have localized the failure. Once the failure is
correlated, the upstream node SHOULD send a ChannelStatus message to
the downstream node indicating that the channel is failed or is ok.
If a ChannelStatus message is not received by the downstream node,
it SHOULD send a ChannelStatusRequest message for the channel in
question. Once the failure has been localized, the signaling
protocols may be used to initiate span or path protection and
restoration procedures.
If all of the data links of a TE link have failed, then the upstream
node MAY be notified of the TE link failure without specifying each
data link of the failed TE link. This is done by sending failure
notification in a ChannelStatus message identifying the TE Link
without including the Interface_Ids in the CHANNEL_STATUS object.
6.3. Examples of Fault Localization
In Fig. 2, a sample network is shown where four nodes are connected
in a linear array configuration. The control channels are bi-
directional and are labeled with a "c". All LSPs are also bi-
directional.
In the first example [see Fig. 2(a)], there is a failure on one
direction of the bi-directional LSP. Node 4 will detect the failure
and will send a ChannelStatus message to Node 3 indicating the
failure (e.g., LOL) to the corresponding upstream node. When Node 3
receives the ChannelStatus message from Node 4, it returns a
ChannelStatusAck message back to Node 4 and correlates the failure
locally. When Node 3 correlates the failure and verifies that the
failure is clear, it has localized the failure to the data link
between Node 3 and Node 4. At that time, Node 3 should send a
ChannelStatus message to Node 4 indicating that the failure has been
localized.
In the second example [see Fig. 2(b)], a single failure (e.g., fiber
cut) affects both directions of the bi-directional LSP. Node 2
(Node 3) will detect the failure of the upstream (downstream)
direction and send a ChannelStatus message to the upstream (in terms
of data flow) node indicating the failure (e.g., LOL).
Simultaneously (ignoring propagation delays), Node 1 (Node 4) will
detect the failure on the upstream (downstream) direction, and will
send a ChannelStatus message to the corresponding upstream (in terms
of data flow) node indicating the failure. Node 2 and Node 3 will
have localized the two directions of the failure.
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+-------+ +-------+ +-------+ +-------+
+ Node1 + + Node2 + + Node3 + + Node4 +
+ +-- c ---+ +-- c ---+ +-- c ---+ +
----+---\ + + + + + + +
<---+---\\--+--------+-------+---\ + + + /--+--->
+ \--+--------+-------+---\\---+-------+---##---+---//--+----
+ + + + \---+-------+--------+---/ +
+ + + + + + (a) + +
----+-------+--------+---\ + + + + +
<---+-------+--------+---\\--+---##---+--\ + + +
+ + + \--+---##---+--\\ + + +
+ + + + (b) + \\--+--------+-------+--->
+ + + + + \--+--------+-------+----
+ + + + + + + +
+-------+ +-------+ +-------+ +-------+
Figure 2: Two types of data link failures are shown
(indicated by ## in the figure): (A) a data link
corresponding to the downstream direction of a bi-directional
LSP fails, (B) two data links corresponding to both
directions of a bi-directional LSP fail. The control channel
connecting two nodes is indicated with a "c".
6.4. Channel Activation Indication
The ChannelStatus message may also be used to notify an LMP neighbor
that the data link should be actively monitored. This is called
Channel Activation Indication. This is particularly useful in
networks with transparent nodes where the status of data links may
need to be triggered using control channel messages. For example,
if a data link is pre-provisioned and the physical link fails after
verification and before inserting user traffic, a mechanism is
needed to indicate the data link should be active or the failure may
not be able to be detected.
The ChannelStatus message is used to indicate that a channel or
group of channels are now active. The ChannelStatusAck message MUST
be transmitted upon receipt of a ChannelStatus message. When a
ChannelStatus message is received, the corresponding data link(s)
MUST be put into the Active state. If upon putting them into the
Active state, a failure is detected, the ChannelStatus message
SHOULD be transmitted as described in Section 6.2.
6.5. Channel Deactivation Indication
The ChannelStatus message may also be used to notify an LMP neighbor
that the data link no longer needs to be actively monitored. This
is the counterpart to the Channel Active Indication.
When a ChannelStatus message is received with Channel Deactive
Indication, the corresponding data link(s) MUST be taken out of the
Active state.
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7. Message_Id Usage
The MESSAGE_ID and MESSAGE_ID_ACK objects are included in LMP
messages to support reliable message delivery. This section
describes the usage of these objects. The MESSAGE_ID and
MESSAGE_ID_ACK objects contain a Message_Id field.
Only one MESSAGE_ID/MESSAGE_ID_ACK object may be included in any LMP
message.
For control channel specific messages, the Message_Id field is
within the scope of the CC_Id. For TE link specific messages, the
Message_Id field is within the scope of the LMP adjacency.
The Message_Id field of the MESSAGE_ID object contains a generator-
selected value. This value MUST be monotonically increasing. A
value is considered to be previously used when it has been sent in
an LMP message with the same CC_Id (for control channel specific
messages) or LMP adjacency (for TE Link specific messages). The
Message_Id field of the MESSAGE_ID_ACK object contains the
Message_Id field of the message being acknowledged.
Unacknowledged messages sent with the MESSAGE_ID object SHOULD be
retransmitted until the message is acknowledged or until a retry
limit is reached (see also Section 10).
Note that the 32-bit Message_Id value MAY wrap. The following
expression may be used to test if a newly received Message_Id value
is less than a previously received value:
If ((int) old_id - (int) new_id > 0) {
New value is less than old value;
}
Nodes processing incoming messages SHOULD check to see if a newly
received message is out of order and can be ignored. Out-of-order
messages can be identified by examining the value in the Message_Id
field. If a message is determined to be out-of-order, that message
should be silently dropped.
If the message is a Config message, and the Message_Id value is less
than the largest Message_Id value previously received from the
sender for the CC_Id, then the message SHOULD be treated as being
out-of-order.
If the message is a LinkSummary message and the Message_Id value is
less than the largest Message_Id value previously received from the
sender for the TE Link, then the message SHOULD be treated as being
out-of-order.
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If the message is a ChannelStatus message and the Message_Id value
is less than the largest Message_Id value previously received from
the sender for the specified TE link, then the receiver SHOULD check
the Message_Id value previously received for the state of each data
channel included in the ChannelStatus message. If the Message_Id
value is greater than the most recently received Message_Id value
associated with at least one of the data channels included in the
message, the message MUST NOT be treated as out of order; otherwise
the message SHOULD be treated as being out of order. However, the
state of any data channel MUST NOT be updated if the Message_Id
value is less than the most recently received Message_Id value
associated with the data channel.
All other messages MUST NOT be treated as out-of-order.
8. Graceful Restart
This section describes the mechanism to resynchronize the LMP state
after a control plane restart. A control plane restart may occur
when bringing up the first control channel after a control
communications failure. A control communications failure may be the
result of an LMP adjacency failure or a nodal failure wherein the
LMP control state is lost, but the data plane is unaffected. The
latter is detected by setting the "LMP Restart" bit in the Common
Header of the LMP messages. When the control plane fails due to the
loss of the control channel, the LMP link information should be
retained. It is possible that a node may be capable of retaining
the LMP link information across a nodal failure. However, in both
cases the status of the data channels MUST be synchronized.
It is assumed the Local Interface_Ids remain stable across a control
plane restart.
After the control plane of a node restarts, the control channel(s)
must be re-established using the procedures of Section 3.1.
If the control plane failure was the result of a nodal failure where
the LMP control state is lost, then the "LMP Restart" flag MUST be
set in LMP messages until a Hello message is received with the
RcvSeqNum equal to the local TxSeqNum. This indicates that the
control channel is up and the LMP neighbor has detected the restart.
The following assumes that the LMP component restart only occurred
on one end of the TE Link. If the LMP component restart occurred on
both ends of the TE Link, the normal procedures for LinkSummary
should be used, as described in Section 4.
Once a control channel is up, the LMP neighbor MUST send a
LinkSummary message for each TE Link across the adjacency. All the
objects of the LinkSummary message MUST have the N-bit set to 0
indicating that the parameters are non-negotiable. This provides
the local/remote Link_Id and Interface_Id mappings, the associated
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data link parameters, and indication of which data links are
currently allocated to user traffic. When a node receives the
LinkSummary message, it checks its local configuration. If the node
is capable of retaining the LMP link information across a restart,
it must process the LinkSummary message as described in Section 4
with the exception that the allocated/de-allocated flag of the
DATA_LINK object received in the LinkSummary message MUST take
precedence over any local value. If, however, the node was not
capable of retaining the LMP link information across a restart, the
node MUST accept the data link parameters of the received
LinkSummary message and respond with a LinkSummaryAck message.
Upon completion of the LinkSummary exchange, the node that has
restarted the control plane SHOULD send a ChannelStatusRequest
message for that TE link. The node SHOULD also verify the
connectivity of all unallocated data channels.
9. Addressing
All LMP messages are run over UDP with an LMP port number (except,
in some cases, the Test messages which may be limited by the
transport mechanism for in-band messaging). The destination address
of the IP packet MAY be either the address learned in the
Configuration procedure (i.e., the Source IP address found in the IP
header of the received Config message), an IP address configured on
the remote node, or the Node_Id. The Config message is an exception
as described below.
The manner in which a Config message is addressed may depend on the
signaling transport mechanism. When the transport mechanism is a
point-to-point link, Config messages SHOULD be sent to the Multicast
address (224.0.0.1). Otherwise, Config messages MUST be sent to an
IP address on the neighboring node. This may be configured at both
ends of the control channel or may be automatically discovered.
10. Exponential Back-off Procedures
This section is based on [RFC2961] and provides exponential back-off
procedures for message retransmission. Implementations MUST use the
described procedures or their equivalent.
10.1. Operation
The following operation is one possible mechanism for exponential
back-off retransmission of unacknowledged LMP messages. The sending
node retransmits the message until an acknowledgement message is
received or until a retry limit is reached. When the sending node
receives the acknowledgement, retransmission of the message is
stopped. The interval between message retransmission is governed by
a rapid retransmission timer. The rapid retransmission timer starts
at a small interval and increases exponentially until it reaches a
threshold.
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The following time parameters are useful to characterize the
procedures:
Rapid retransmission interval Ri:
Ri is the initial retransmission interval for unacknowledged
messages. After sending the message for the first time, the
sending node will schedule a retransmission after Ri
milliseconds.
Rapid retry limit Rl:
Rl is the maximum number of times a message will be transmitted
without being acknowledged.
Increment value Delta:
Delta governs the speed with which the sender increases the
retransmission interval. The ratio of two successive
retransmission intervals is (1 + Delta).
Suggested default values for an initial retransmission interval (Ri)
of 500ms, a power of 2 exponential back-off (Delta = 1) and a retry
limit of 3.
10.2. Retransmission Algorithm
After a node transmits a message requiring acknowledgement, it
should immediately schedule a retransmission after Ri seconds. If a
corresponding acknowledgement message is received before Ri seconds,
then message retransmission SHOULD be canceled. Otherwise, it will
retransmit the message after (1+Delta)*Ri seconds. The
retransmission will continue until either an appropriate
acknowledgement message is received or the rapid retry limit, Rl,
has been reached.
A sending node can use the following algorithm when transmitting a
message that requires acknowledgement:
Prior to initial transmission, initialize Rk = Ri and Rn = 0.
while (Rn++ < Rl) {
transmit the message;
wake up after Rk milliseconds;
Rk = Rk * (1 + Delta);
}
/* acknowledged message or no reply from receiver and Rl
reached*/
do any needed clean up;
exit;
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Asynchronously, when a sending node receives a corresponding
acknowledgment message, it will change the retry count, Rn, to Rl.
Note that the transmitting node does not advertise or negotiate the
use of the described exponential back-off procedures in the Config
or LinkSummary messages.
11. LMP Finite State Machines
11.1. Control Channel FSM
The control channel FSM defines the states and logics of operation
of an LMP control channel.
11.1.1. Control Channel States
A control channel can be in one of the states described below.
Every state corresponds to a certain condition of the control
channel and is usually associated with a specific type of LMP
message that is periodically transmitted to the far end.
Down: This is the initial control channel state. In this
state, no attempt is being made to bring the control
channel up and no LMP messages are sent. The control
channel parameters should be set to the initial values.
ConfSnd: The control channel is in the parameter negotiation
state. In this state the node periodically sends a
Config message, and is expecting the other side to
reply with either a ConfigAck or ConfigNack message.
The FSM does not transition into the Active state until
the remote side positively acknowledges the parameters.
ConfRcv: The control channel is in the parameter negotiation
state. In this state, the node is waiting for
acceptable configuration parameters from the remote
side. Once such parameters are received and
acknowledged, the FSM can transition to the Active
state.
Active: In this state the node periodically sends a Hello
message and is waiting to receive a valid Hello
message. Once a valid Hello message is received, it
can transition to the up state.
Up: The CC is in an operational state. The node receives
valid Hello messages and sends Hello messages.
GoingDown: A CC may go into this state because of administrative
action. While a CC is in this state, the node sets the
ControlChannelDown bit in all the messages it sends.
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11.1.2. Control Channel Events
Operation of the LMP control channel is described in terms of FSM
states and events. Control channel events are generated by the
underlying protocols and software modules, as well as by the packet
processing routines and FSMs of associated TE links. Every event
has its number and a symbolic name. Description of possible control
channel events is given below.
1 : evBringUp: This is an externally triggered event indicating
that the control channel negotiation should begin.
This event, for example, may be triggered by an
operator command, by the successful completion of
a control channel bootstrap procedure, or by
configuration. Depending on the configuration,
this will trigger either
1a) the sending of a Config message,
1b) a period of waiting to receive a Config
message from the remote node.
2 : evCCDn: This event is generated when there is indication
that the control channel is no longer available.
3 : evConfDone: This event indicates a ConfigAck message has been
received, acknowledging the Config parameters.
4 : evConfErr: This event indicates a ConfigNack message has been
received, rejecting the Config parameters.
5 : evNewConfOK: New Config message was received from neighbor and
positively acknowledged.
6 : evNewConfErr: New Config message was received from neighbor and
rejected with a ConfigNack message.
7 : evContenWin: New Config message was received from neighbor at
the same time a Config message was sent to the
neighbor. The local node wins the contention. As
a result, the received Config message is ignored.
8 : evContenLost: New Config message was received from neighbor at
the same time a Config message was sent to the
neighbor. The local node loses the contention.
8a) The Config message is positively
acknowledged.
8b) The Config message is negatively
acknowledged.
9 : evAdminDown: The administrator has requested that the control
channel is brought down administratively.
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10: evNbrGoesDn: A packet with ControlChannelDown flag is received
from the neighbor.
11: evHelloRcvd: A Hello packet with expected SeqNum has been
received.
12: evHoldTimer: The HelloDeadInterval timer has expired indicating
that no Hello packet has been received. This
moves the control channel back into the
Negotiation state, and depending on the local
configuration, this will trigger either
12a) the sending of periodic Config messages,
12b) a period of waiting to receive Config
messages from the remote node.
13: evSeqNumErr: A Hello with unexpected SeqNum received and
discarded.
14: evReconfig: Control channel parameters have been reconfigured
and require renegotiation.
15: evConfRet: A retransmission timer has expired and a Config
message is resent.
16: evHelloRet: The HelloInterval timer has expired and a Hello
packet is sent.
17: evDownTimer: A timer has expired and no messages have been
received with the ControlChannelDown flag set.
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11.1.3. Control Channel FSM Description
Figure 3 illustrates operation of the control channel FSM
in a form of FSM state transition diagram.
+--------+
+----------------->| |<--------------+
| +--------->| Down |<----------+ |
| |+---------| |<-------+ | |
| || +--------+ | | |
| || | ^ 2,9| 2| 2|
| ||1b 1a| | | | |
| || v |2,9 | | |
| || +--------+ | | |
| || +->| |<------+| | |
| || 4,7,| |ConfSnd | || | |
| || 14,15+--| |<----+ || | |
| || +--------+ | || | |
| || 3,8a| | | || | |
| || +---------+ |8b 14,12a| || | |
| || | v | || | |
| |+-|------>+--------+ | || | |
| | | +->| |-----|-|+ | |
| | |6,14| |ConfRcv | | | | |
| | | +--| |<--+ | | | |
| | | +--------+ | | | | |
| | | 5| ^ | | | | |
| | +---------+ | | | | | | |
| | | | | | | | | |
| | v v |6,12b | | | | |
| |10 +--------+ | | | | |
| +----------| | | | | | |
| | +--| Active |---|-+ | | |
10,17| | 5,16| | |-------|---+ |
+-------+ 9 | 13 +->| | | | |
| Going |<--|----------+--------+ | | |
| Down | | 11| ^ | | |
+-------+ | | |5 | | |
^ | v | 6,12b| | |
|9 |10 +--------+ | |12a,14 |
| +----------| |---+ | |
| | Up |-------+ |
+------------------| |---------------+
+--------+
| ^
| |
+---+
11,13,16
Figure 3: Control Channel FSM
J. Lang, Editor Standards Track [Page 30]
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Event evCCDn always forces the FSM to the down state. Events
evHoldTimer evReconfig always force the FSM to the Negotiation state
(either ConfSnd or ConfRcv).
11.2. TE Link FSM
The TE Link FSM defines the states and logics of operation of the
LMP TE Link.
11.2.1. TE Link States
An LMP TE link can be in one of the states described below. Every
state corresponds to a certain condition of the TE link and is
usually associated with a specific type of LMP message that is
periodically transmitted to the far end via the associated control
channel or in-band via the data links.
Down: There are no data links allocated to the TE link.
Init: Data links have been allocated to the TE link, but the
configuration has not yet been synchronized with the LMP
neighbor.
Up: This is the normal operational state of the TE link. At
least one LMP control channel is required to be
operational between the nodes sharing the TE link.
Degraded: In this state, all LMP control channels are down, but
the TE link still includes some data links that are
allocated to user traffic.
11.2.2. TE Link Events
Operation of the LMP TE link is described in terms of FSM states and
events. TE Link events are generated by the packet processing
routines and by the FSMs of the associated control channel(s) and
the data links. Every event has its number and a symbolic name.
Description of possible events is given below.
1 : evDCUp: One or more data channels have been enabled and
assigned to the TE Link.
2 : evSumAck: LinkSummary message received and positively
acknowledged.
3 : evSumNack: LinkSummary message received and negatively
acknowledged.
4 : evRcvAck: LinkSummaryAck message received acknowledging
the TE Link Configuration.
5 : evRcvNack: LinkSummaryNack message received.
6 : evSumRet: Retransmission timer has expired and LinkSummary
message is resent.
7 : evCCUp: First active control channel goes up.
8 : evCCDown: Last active control channel goes down.
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9 : evDCDown: Last data channel of TE Link has been removed.
11.2.3. TE Link FSM Description
Figure 4 illustrates operation of the LMP TE Link FSM in a form of
FSM state transition diagram.
3,7,8
+--+
| |
| v
+--------+
| |
+------------>| Down |<---------+
| | | |
| +--------+ |
| | ^ |
| 1| |9 |
| v | |
| +--------+ |
| | |<-+ |
| | Init | |3,5,6 |9
| | |--+ 7,8 |
9| +--------+ |
| | |
| 2,4| |
| v |
+--------+ 7 +--------+ |
| |------>| |----------+
| Deg | | Up |
| |<------| |
+--------+ 8 +--------+
| ^
| |
+--+
2,3,4,5,6
Figure 4: LMP TE Link FSM
In the above FSM, the sub-states that may be implemented when the
link verification procedure is used have been omitted.
11.3. Data Link FSM
The data link FSM defines the states and logics of operation of a
data link within an LMP TE link. Operation of a data link is
described in terms of FSM states and events. Data links can either
be in the active (transmitting) mode, where Test messages are
transmitted from them, or the passive (receiving) mode, where Test
messages are received through them. For clarity, separate FSMs are
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defined for the active/passive data links; however, a single set of
data link states and events are defined.
11.3.1. Data Link States
Any data link can be in one of the states described below. Every
state corresponds to a certain condition of the data link.
Down: The data link has not been put in the resource pool
(i.e., the link is not æin serviceÆ)
Test: The data link is being tested. An LMP Test message
is periodically sent through the link.
PasvTest: The data link is being checked for incoming test
messages.
Up/Free: The link has been successfully tested and is now put
in the pool of resources (in-service). The link has
not yet been allocated to data traffic.
Up/Alloc: The link is up and has been allocated for data
traffic.
11.3.2. Data Link Events
Data link events are generated by the packet processing routines and
by the FSMs of the associated control channel and the TE link.
Every event has its number and a symbolic name. Description of
possible data link events is given below:
1 :evCCUp: First active control channel goes up.
2 :evCCDown: LMP neighbor connectivity is lost. This indicates
the last LMP control channel has failed between
neighboring nodes.
3 :evStartTst: This is an external event that triggers the sending
of Test messages over the data link.
4 :evStartPsv: This is an external event that triggers the
listening for Test messages over the data link.
5 :evTestOK: Link verification was successful and the link can
be used for path establishment.
(a) This event indicates the Link Verification
procedure (see Section 5) was successful
for this data link and a TestStatusSuccess
message was received over the control
channel.
(b) This event indicates the link is ready for
path establishment, but the Link
Verification procedure was not used. For
in-band signaling of the control channel,
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the control channel establishment may be
sufficient to verify the link.
6 :evTestRcv: Test message was received over the data port and a
TestStatusSuccess message is transmitted over the
control channel.
7 :evTestFail: Link verification returned negative results. This
could be because (a) a TestStatusFailure message
was received, or (b) the Verification procedure has
ended without receiving a TestStatusSuccess or
TestStatusFailure message for the data link.
8 :evPsvTestFail:Link verification returned negative results. This
indicates that a Test message was not detected and
either (a) the VerifyDeadInterval has expired or
(b) the Verification procedure has ended and the
VerifyDeadInterval has not yet expired.
9 :evLnkAlloc: The data link has been allocated.
10:evLnkDealloc: The data link has been de-allocated.
11:evTestRet: A retransmission timer has expired and the Test
message is resent.
12:evSummaryFail:The LinkSummary did not match for this data port.
13:evLocalizeFail:A Failure has been localized to this data link.
14:evdcDown: The data channel is no longer available.
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11.3.3. Active Data Link FSM Description
Figure 5 illustrates operation of the LMP active data link FSM in a
form of FSM state transition diagram.
+------+
| |<-------+
+--------->| Down | |
| +----| |<-----+ |
| | +------+ | |
| |5b 3| ^ | |
| | | |7 | |
| | v | | |
| | +------+ | |
| | | |<-+ | |
| | | Test | |11 | |
| | | |--+ | |
| | +------+ | |
| | 5a| 3^ | |
| | | | | |
| | v | | |
|12 | +---------+ | |
| +-->| |14 | |
| | Up/Free |----+ |
+---------| | |
+---------+ |
9| ^ |
| | |
v |10 |
+---------+ |
| |13 |
|Up/Alloc |------+
| |
+---------+
Figure 5: Active LMP Data Link FSM
J. Lang, Editor Standards Track [Page 35]
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11.3.4. Passive Data Link FSM Description
Figure 6 illustrates operation of the LMP passive data link FSM in a
form of FSM state transition diagram.
+------+
| |<------+
+---------->| Down | |
| +-----| |<----+ |
| | +------+ | |
| |5b 4| ^ | |
| | | |8 | |
| | v | | |
| | +----------+ | |
| | | PasvTest | | |
| | +----------+ | |
| | 6| 4^ | |
| | | | | |
| | v | | |
|12 | +---------+ | |
| +--->| Up/Free |14 | |
| | |---+ |
+----------| | |
+---------+ |
9| ^ |
| | |
v |10 |
+---------+ |
| |13 |
|Up/Alloc |-----+
| |
+---------+
Figure 6: Passive LMP Data Link FSM
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12. LMP Message Formats
All LMP messages are run over UDP with an LMP port number (except,
in some cases, the Test messages are limited by the transport
mechanism for in-band messaging) and run over UDP with port number
xxx - TBA (to be assigned) by IANA.
12.1. Common Header
In addition to the UDP header and standard IP header, all LMP
messages (except, in some cases, the Test messages which may be
limited by the transport mechanism for in-band messaging) have the
following common header:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Vers | (Reserved) | Flags | Msg Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LMP Length | (Reserved) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Reserved field should be sent as zero and ignored on receipt.
All values are defined in network byte order (i.e., big-endian byte
order).
Vers: 4 bits
Protocol version number. This is version 1.
Flags: 8 bits. The following values are defined. All other values
are reserved and should be sent as zero and ignored on
receipt.
0x01: ControlChannelDown
0x02: LMP Restart
This bit is set to indicate that a nodal failure has
occured and the LMP control state has been lost. This
flag may be reset to 0 when a Hello message is received
with RcvSeqNum equal to the local TxSeqNum.
Msg Type: 8 bits. The following values are defined. All other
values are reserved and should be sent as zero and ignored
on receipt.
1 = Config
2 = ConfigAck
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3 = ConfigNack
4 = Hello
5 = BeginVerify
6 = BeginVerifyAck
7 = BeginVerifyNack
8 = EndVerify
9 = EndVerifyAck
10 = Test
11 = TestStatusSuccess
12 = TestStatusFailure
13 = TestStatusAck
14 = LinkSummary
15 = LinkSummaryAck
16 = LinkSummaryNack
17 = ChannelStatus
18 = ChannelStatusAck
19 = ChannelStatusRequest
20 = ChannelStatusResponse
All of the messages are sent over the control channel EXCEPT
the Test message, which is sent over the data link that is
being tested.
LMP Length: 16 bits
The total length of this LMP message in bytes, including the
common header and any variable-length objects that follow.
12.2. LMP Object Format
LMP messages are built using objects. Each object is identified by
its Object Class and Class-type. Each object has a name, which is
always capitalized in this document. LMP objects can be either
negotiable or non-negotiable (identified by the N bit in the object
header). Negotiable objects can be used to let the devices agree on
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certain values. Non-negotiable objects are used for announcement of
specific values that do not need or do not allow negotiation.
All values are defined in network byte order (i.e., big-endian byte
order).
The format of the LMP object is as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|N| C-Type | Class | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// (object contents) //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
N: 1 bit
The N flag indicates if the object is negotiable (N=1) or non-
negotiable (N=0).
C-Type: 7 bits
Class-type, unique within an Object Class. Values are defined
in Section 13.
Class: 8 bits
The Class indicates the object type. Each object has a name,
which is always capitalized in this document.
Length: 16 bits
The Length field indicates the length of the object in bytes,
including the N, C-Type, Class, and Length fields.
12.3. Parameter Negotiation Messages
12.3.1. Config Message (Msg Type = 1)
The Config message is used in the control channel negotiation phase
of LMP. The contents of the Config message are built using LMP
objects. The format of the Config message is as follows:
<Config Message> ::= <Common Header> <LOCAL_CCID> <MESSAGE_ID>
<LOCAL_NODE_ID> <CONFIG>
The above transmission order SHOULD be followed.
The MESSAGE_ID object is within the scope of the LOCAL_CCID object.
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The Config message MUST be periodically transmitted until (1) it
receives a ConfigAck or ConfigNack message, (2) a retry limit has
been reached and no ConfigAck or ConfigNack message has been
received, or (3) it receives a Config message from the remote node
and has lost the contention (e.g., the Node_Id of the remote node is
higher than the Node_Id of the local node). Both the retransmission
interval and the retry limit are local configuration parameters.
12.3.2. ConfigAck Message (Msg Type = 2)
The ConfigAck message is used to acknowledge receipt of the Config
message and indicate agreement on all parameters.
<ConfigAck Message> ::= <Common Header> <LOCAL_CCID> <LOCAL_NODE_ID>
<REMOTE_CCID> <MESSAGE_ID_ACK>
<REMOTE_NODE_ID>
The above transmission order SHOULD be followed.
The contents of the REMOTE_CCID, MESSAGE_ID_ACK, and REMOTE_NODE_ID
objects MUST be obtained from the Config message being acknowledged.
12.3.3. ConfigNack Message (Msg Type = 3)
The ConfigNack message is used to acknowledge receipt of the Config
message and indicate disagreement on non-negotiable parameters or
propose other values for negotiable parameters. Parameters where
agreement was reached MUST NOT be included in the ConfigNack
Message. The format of the ConfigNack message is as follows:
<ConfigNack Message> ::= <Common Header> <LOCAL_CCID>
<LOCAL_NODE_ID> <REMOTE_CCID>
<MESSAGE_ID_ACK> <REMOTE_NODE_ID> <CONFIG>
The above transmission order SHOULD be followed.
The contents of the REMOTE_CCID, MESSAGE_ID_ACK, and REMOTE_NODE_ID
objects MUST be obtained from the Config message being negatively
acknowledged.
It is possible that multiple parameters may be invalid in the Config
message.
If a negotiable CONFIG object is included in the ConfigNack message,
it MUST include acceptable values for the parameters.
If the ConfigNack message includes CONFIG objects for non-negotiable
parameters, they MUST be copied from the CONFIG objects received in
the Config message.
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If the ConfigNack message is received and only includes CONFIG
objects that are negotiable, then a new Config message SHOULD be
sent. The values in the CONFIG object of the new Config message
SHOULD take into account the acceptable values included in the
ConfigNack message.
12.4. Hello Message (Msg Type = 4)
The format of the Hello message is as follows:
<Hello Message> ::= <Common Header> <LOCAL_CCID> <HELLO>
The above transmission order SHOULD be followed.
The Hello message MUST be periodically transmitted at least once
every HelloInterval msec. If no Hello message is received within
the HelloDeadInterval, the control channel is assumed to have
failed.
12.5. Link Verification Messages
12.5.1. BeginVerify Message (Msg Type = 5)
The BeginVerify message is sent over the control channel and is used
to initiate the link verification process. The format is as
follows:
<BeginVerify Message> ::= <Common Header> <LOCAL_LINK_ID>
<MESSAGE_ID> [<REMOTE_LINK_ID>]
<BEGIN_VERIFY>
The above transmission order SHOULD be followed.
To limit the scope of Link Verification to a particular TE Link, the
Link_Id field of the LOCAL_LINK_ID object MUST be non-zero. If this
field is zero, the data links can span multiple TE links and/or they
may comprise a TE link that is yet to be configured. In the special
case where the local Link_Id field is zero, the "Verify all Links"
flag of the BEGIN_VERIFY object is used to distinguish between data
links that span multiple TE links and those that have not yet been
assigned to a TE link (see Section 5).
The REMOTE_LINK_ID object may be included if the local/remote
Link_Id mapping is known.
The Link_Id field of the REMOTE_LINK_ID object MUST be non-zero if
included.
The BeginVerify message MUST be periodically transmitted until (1)
the node receives either a BeginVerifyAck or BeginVerifyNack message
to accept or reject the verify process or (2) a retry limit has been
reached and no BeginVerifyAck or BeginVerifyNack message has been
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received. Both the retransmission interval and the retry limit are
local configuration parameters.
12.5.2. BeginVerifyAck Message (Msg Type = 6)
When a BeginVerify message is received and Test messages are ready
to be processed, a BeginVerifyAck message MUST be transmitted.
<BeginVerifyAck Message> ::= <Common Header> [<LOCAL_LINK_ID>]
<MESSAGE_ID_ACK> <BEGIN_VERIFY_ACK>
<VERIFY_ID>
The above transmission order SHOULD be followed.
The LOCAL_LINK_ID object may be included if the local/remote Link_Id
mapping is known or learned through the BeginVerify message.
The Link_Id field of the LOCAL_LINK_ID MUST be non-zero if included.
The contents of the MESSAGE_ID_ACK object MUST be obtained from the
BeginVerify message being acknowledged.
The VERIFY_ID object contains a node-unique value that is assigned
by the generator of the BeginVerifyAck message. This value is used
to uniquely identify the Verification process from multiple LMP
neighbors and/or parallel Test procedures between the same LMP
neighbors.
12.5.3. BeginVerifyNack Message (Msg Type = 7)
If a BeginVerify message is received and a node is unwilling or
unable to begin the Verification procedure, a BeginVerifyNack
message MUST be transmitted.
<BeginVerifyNack Message> ::= <Common Header> [<LOCAL_LINK_ID>]
<MESSAGE_ID_ACK> <ERROR_CODE>
The above transmission order SHOULD be followed.
The contents of the MESSAGE_ID_ACK object MUST be obtained from the
BeginVerify message being negatively acknowledged.
If the Verification process is not supported, the ERROR_CODE MUST
indicate "Link Verification Procedure not supported".
If Verification is supported, but the node unable to begin the
procedure, the ERROR_CODE MUST indicate "Unwilling to verify". If a
BeginVerifyNack message is received with such an ERROR_CODE, the
node that originated the BeginVerify SHOULD schedule a BeginVerify
retransmission after Rf seconds, where Rf is a locally defined
parameter.
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If the Verification Transport mechanism is not supported, the
ERROR_CODE MUST indicate, "Unsupported verification transport
mechanism".
If remote configuration of the Link_Id is not supported and the
contents of the REMOTE_LINK_ID object (included in the BeginVerify
message) does not match any configured values, the ERROR_CODE MUST
indicate "Link_Id configuration error".
12.5.4. EndVerify Message (Msg Type = 8)
The EndVerify message is sent over the control channel and is used
to terminate the link verification process. The EndVerify message
may be sent at any time the initiating node desires to end the
Verify procedure. The format is as follows:
<EndVerify Message> ::= <Common Header> <MESSAGE_ID> <VERIFY_ID>
The above transmission order SHOULD be followed.
The EndVerify message will be periodically transmitted until (1) an
EndVerifyAck message has been received or (2) a retry limit has been
reached and no EndVerifyAck message has been received. Both the
retransmission interval and the retry limit are local configuration
parameters.
12.5.5. EndVerifyAck Message (Msg Type =9)
The EndVerifyAck message is sent over the control channel and is
used to acknowledge the termination of the link verification
process. The format is as follows:
<EndVerifyAck Message> ::= <Common Header> <MESSAGE_ID_ACK>
<VERIFY_ID>
The above transmission order SHOULD be followed.
The contents of the MESSAGE_ID_ACK object MUST be obtained from the
EndVerify message being acknowledged.
12.5.6. Test Message (Msg Type = 10)
The Test message is transmitted over the data link and is used to
verify its physical connectivity. Unless explicitly stated, these
messages MUST be transmitted over UDP like all other LMP messages.
The format of the Test messages is as follows:
<Test Message> ::= <Common Header> <LOCAL_INTERFACE_ID> <VERIFY_ID>
The above transmission order SHOULD be followed.
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Note that this message is sent over a data link and NOT over the
control channel. The transport mechanism for the Test message is
negotiated using Verify Transport Mechanism field of the
BEGIN_VERIFY object and the Verify Transport Response field of the
BEGIN_VERIFY_ACK object (see Sections 13.8 and 13.9).
The local (transmitting) node sends a given Test message
periodically (at least once every VerifyInterval ms) on the
corresponding data link until (1) it receives a correlating
TestStatusSuccess or TestStatusFailure message on the control
channel from the remote (receiving) node or (2) all active control
channels between the two nodes have failed. The remote node will
send a given TestStatus message periodically over the control
channel until it receives either a correlating TestStatusAck message
or an EndVerify message is received over the control channel.
12.5.7. TestStatusSuccess Message (Msg Type = 11)
The TestStatusSuccess message is transmitted over the control
channel and is used to transmit the mapping between the local
Interface_Id and the Interface_Id that was received in the Test
message.
<TestStatusSuccess Message> ::= <Common Header> <LOCAL_LINK_ID>
<MESSAGE_ID> <LOCAL_INTERFACE_ID>
<REMOTE_INTERFACE_ID> <VERIFY_ID>
The above transmission order SHOULD be followed.
The contents of the REMOTE_INTERFACE_ID object MUST be obtained from
the corresponding Test message being positively acknowledged.
12.5.8. TestStatusFailure Message (Msg Type = 12)
The TestStatusFailure message is transmitted over the control
channel and is used to indicate that the Test message was not
received.
<TestStatusFailure Message> ::= <Common Header> <MESSAGE_ID>
<VERIFY_ID>
The above transmission order SHOULD be followed.
12.5.9. TestStatusAck Message (Msg Type = 13)
The TestStatusAck message is used to acknowledge receipt of the
TestStatusSuccess or TestStatusFailure messages.
<TestStatusAck Message> ::= <Common Header> <MESSAGE_ID_ACK>
<VERIFY_ID>
The above transmission order SHOULD be followed.
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The contents of the MESSAGE_ID_ACK object MUST be obtained from the
TestStatusSuccess or TestStatusFailure message being acknowledged.
12.6. Link Summary Messages
12.6.1. LinkSummary Message (Msg Type = 14)
The LinkSummary message is used to synchronize the Interface_Ids and
correlate the properties of the TE link. The format of the
LinkSummary message is as follows:
<LinkSummary Message> ::= <Common Header> <MESSAGE_ID> <TE_LINK>
<DATA_LINK> [<DATA_LINK>...]
The above transmission order SHOULD be followed.
The LinkSummary message can be exchanged at any time a link is not
in the Verification process. The LinkSummary message MUST be
periodically transmitted until (1) the node receives a
LinkSummaryAck or LinkSummaryNack message or (2) a retry limit has
been reached and no LinkSummaryAck or LinkSummaryNack message has
been received. Both the retransmission interval and the retry limit
are local configuration parameters.
12.6.2. LinkSummaryAck Message (Msg Type = 15)
The LinkSummaryAck message is used to indicate agreement on the
Interface_Id synchronization and acceptance/agreement on all the
link parameters. It is on the reception of this message that the
local node makes the Link_Id associations.
<LinkSummaryAck Message> ::= <Common Header> <MESSAGE_ID_ACK>
The above transmission order SHOULD be followed.
12.6.3. LinkSummaryNack Message (Msg Type = 16)
The LinkSummaryNack message is used to indicate disagreement on non-
negotiated parameters or propose other values for negotiable
parameters. Parameters where agreement was reached MUST NOT be
included in the LinkSummaryNack message.
<LinkSummaryNack Message> ::= <Common Header> <MESSAGE_ID_ACK>
<ERROR_CODE> [<DATA_LINK>...]
The above transmission order SHOULD be followed.
The DATA_LINK objects MUST include acceptable values for all
negotiable parameters. If the LinkSummaryNack includes DATA_LINK
objects for non-negotiable parameters, they MUST be copied from the
DATA_LINK objects received in the LinkSummary message.
J. Lang, Editor Standards Track [Page 45]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
If the LinkSummaryNack message is received and only includes
negotiable parameters, then a new LinkSummary message SHOULD be
sent. The values received in the new LinkSummary message SHOULD
take into account the acceptable parameters included in the
LinkSummaryNack message.
12.7. Fault Management Messages
12.7.1. ChannelStatus Message (Msg Type = 17)
The ChannelStatus message is sent over the control channel and is
used to notify an LMP neighbor of the status of a data link. A node
that receives a ChannelStatus message MUST respond with a
ChannelStatusAck message. The format is as follows:
<ChannelStatus Message> ::= <Common Header> <LOCAL_LINK_ID>
<MESSAGE_ID> <CHANNEL_STATUS>
The above transmission order SHOULD be followed.
If the CHANNEL_STATUS object does not include any Interface_Ids,
then this indicates the entire TE Link has failed.
12.7.2. ChannelStatusAck Message (Msg Type = 18)
The ChannelStatusAck message is used to acknowledge receipt of the
ChannelStatus Message. The format is as follows:
<ChannelStatusAck Message> ::= <Common Header> <MESSAGE_ID_ACK>
The above transmission order SHOULD be followed.
The contents of the MESSAGE_ID_ACK object MUST be obtained from the
ChannelStatus message being acknowledged.
12.7.3. ChannelStatusRequest Message (Msg Type = 19)
The ChannelStatusRequest message is sent over the control channel
and is used to request the status of one or more data link(s). A
node that receives a ChannelStatusRequest message MUST respond with
a ChannelStatusResponse message. The format is as follows:
<ChannelStatusRequest Message> ::= <Common Header> <LOCAL_LINK_ID>
<MESSAGE_ID>
[<CHANNEL_STATUS_REQUEST>]
The above transmission order SHOULD be followed.
If the CHANNEL_STATUS_REQUEST object is not included, then the
ChannelStatusRequest is being used to request the status of ALL of
the data link(s) of the TE Link.
J. Lang, Editor Standards Track [Page 46]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
12.7.4. ChannelStatusResponse Message (Msg Type = 20)
The ChannelStatusResponse message is used to acknowledge receipt of
the ChannelStatusRequest Message and notify the LMP neighbor of the
status of the data channel(s). The format is as follows:
<ChannelStatusResponse Message> ::= <Common Header> <MESSAGE_ID_ACK>
<CHANNEL_STATUS>
The above transmission order SHOULD be followed.
The contents of the MESSAGE_ID_ACK objects MUST be obtained from the
ChannelStatusRequest message being acknowledged.
13. LMP Object Definitions
13.1. CCID (Control Channel ID) Class
Class = 1.
o C-Type = 1, LOCAL_CCID
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CC_Id |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
CC_Id: 32 bits
This MUST be node-wide unique and non-zero. The CC_Id
identifies the control channel of the sender associated with
the message.
This object is non-negotiable.
o C-Type = 2, REMOTE_CCID
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CC_Id |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
CC_Id: 32 bits
This identifies the remote nodeÆs CC_Id and MUST be non-zero.
This object is non-negotiable.
J. Lang, Editor Standards Track [Page 47]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
13.2. NODE_ID Class
Class = 2.
o C-Type = 1, LOCAL_NODE_ID
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Node_Id (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Node_Id:
This identities the node that originated the LMP packet.
This object is non-negotiable.
o C-Type = 2, REMOTE_NODE_ID
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Node_Id (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Node_Id:
This identities the remote node.
This object is non-negotiable.
13.3. LINK_ID Class
Class = 3
o C-Type = 1, IPv4 LOCAL_LINK_ID
o C-Type = 2, IPv4 REMOTE_LINK_ID
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link_Id (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o C-Type = 3, IPv6 LOCAL_LINK_ID
o C-Type = 4, IPv6 REMOTE_LINK_ID
J. Lang, Editor Standards Track [Page 48]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Link_Id (16 bytes) +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o C-Type = 5, Unnumbered LOCAL_LINK_ID
o C-Type = 6, Unnumbered REMOTE_LINK_ID
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link_Id (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Link_Id:
For LOCAL_LINK_ID, this identifies the senderÆs Link associated
with the message. This value MUST be non-zero.
For REMOTE_LINK_ID, this identifies the remote nodeÆs Link_Id
and MUST be non-zero.
This object is non-negotiable.
13.4. INTERFACE_ID Class
Class = 4
o C-Type = 1, IPv4 LOCAL_INTERFACE_ID
o C-Type = 2, IPv4 REMOTE_INTERFACE_ID
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface_Id (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o C-Type = 3, IPv6 LOCAL_INTERFACE_ID
o C-Type = 4, IPv6 REMOTE_INTERFACE_ID
J. Lang, Editor Standards Track [Page 49]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Interface_Id (16 bytes) +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o C-Type = 5, Unnumbered LOCAL_INTERFACE_ID
o C-Type = 6, Unnumbered REMOTE_INTERFACE_ID
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface_Id (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Interface_Id:
For the LOCAL_INTERFACE_ID, this identifies the data link.
This value MUST be node-wide unique and non-zero.
For the REMOTE_INTERFACE_ID, this identifies the remote nodeÆs
data link. The Interface_Id MUST be non-zero.
This object is non-negotiable.
13.5. MESSAGE_ID Class
Class = 5.
o C-Type=1, MessageId
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message_Id |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Message_Id:
The Message_Id field is used to identify a message. This value
is incremented and only decreases when the value wraps. This
is used for message acknowledgment.
This object is non-negotiable.
J. Lang, Editor Standards Track [Page 50]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
o C-Type = 2, MessageIdAck
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message_Id |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Message_Id:
The Message_Id field is used to identify the message being
acknowledged. This value is copied from the MESSAGE_ID object
of the message being acknowledged.
This object is non-negotiable.
13.6. CONFIG Class
Class = 6.
o C-Type = 1, HelloConfig
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| HelloInterval | HelloDeadInterval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
HelloInterval: 16 bits.
Indicates how frequently the Hello packets will be sent and is
measured in milliseconds (ms).
HelloDeadInterval: 16 bits.
If no Hello packets are received within the HelloDeadInterval,
the control channel is assumed to have failed. The
HelloDeadInterval is measured in milliseconds (ms). The
HelloDeadInterval MUST be greater than the HelloInterval, and
SHOULD be at least 3 times the value of HelloInterval.
If the fast keep-alive mechanism of LMP is not used, the
HelloInterval and HelloDeadInterval MUST be set to zero.
13.7. HELLO Class
Class = 7
o C-Type = 1, Hello
J. Lang, Editor Standards Track [Page 51]
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TxSeqNum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RcvSeqNum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
TxSeqNum: 32 bits
This is the current sequence number for this Hello message.
This sequence number will be incremented when the sequence
number is reflected in the RcvSeqNum of a Hello packet that is
received over the control channel.
TxSeqNum=0 is not allowed.
TxSeqNum=1 is used to indicate that the this is the first Hello
message sent over the control channel.
RcvSeqNum: 32 bits
This is the sequence number of the last Hello message received
over the control channel. RcvSeqNum=0 is used to indicate that
a Hello message has not yet been received.
This object is non-negotiable.
13.8. BEGIN_VERIFY Class
Class = 8.
o C-Type = 1
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | VerifyInterval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number of Data Links |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| EncType | (Reserved) | Verify Transport Mechanism |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TransmissionRate |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Wavelength |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Reserved field should be sent as zero and ignored on receipt.
J. Lang, Editor Standards Track [Page 52]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
Flags: 16 bits
The following flags are defined:
0x01 Verify all Links
If this bit is set, the verification process checks all
unallocated links; else it only verifies new ports or
component links that are to be added to this TE link.
0x02 Data Link Type
If set, the data links to be verified are ports,
otherwise they are component links
VerifyInterval: 16 bits
This is the interval between successive Test messages and is
measured in milliseconds (ms).
Number of Data Links: 32 bits
This is the number of data links that will be verified.
EncType: 8 bits
This is the encoding type of the data link. The defined
EncType values are consistent with the LSP Encoding Type values
of [GMPLS-SIG].
Verify Transport Mechanism: 16 bits
This defines the transport mechanism for the Test Messages.
The scope of this bit mask is restricted to each LSP encoding
type. The local node will set the bits corresponding to the
various mechanisms it can support for transmitting LMP test
messages. The receiver chooses the appropriate mechanism in
the BeginVerifyAck message.
The following flag is defined across all LSP Encoding Types.
All other flags are dependent on the LSP Encoding Type.
0x8000 Payload: Test Message transmitted in the payload
Capable of transmitting Test messages in the payload.
The Test message is sent as an IP packet as defined
above.
TransmissionRate: 32 bits
This is the transmission rate of the data link over which the
Test messages will be transmitted. This is expressed in bytes
per second and represented in IEEE floating-point format.
J. Lang, Editor Standards Track [Page 53]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
Wavelength: 32 bits
When a data link is assigned to a port or component link that
is capable of transmitting multiple wavelengths (e.g., a fiber
or waveband-capable port), it is essential to know which
wavelength the test messages will be transmitted over. This
value corresponds to the wavelength at which the Test messages
will be transmitted over and has local significance. If there
is no ambiguity as to the wavelength over which the message
will be sent, then this value SHOULD be set to 0.
13.9. BEGIN_VERIFY_ACK Class
Class = 9.
o C-Type = 1
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VerifyDeadInterval | Verify_Transport_Response |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
VerifyDeadInterval: 16 bits
If a Test message is not detected within the
VerifyDeadInterval, then a node will send the TestStatusFailure
message for that data link.
Verify_Transport_Response: 16 bits
The recipient of the BeginVerify message (and the future
recipient of the TEST messages) chooses the transport mechanism
from the various types that are offered by the transmitter of
the Test messages. One and only one bit MUST be set in the
verification transport response.
This object is non-negotiable.
13.10. VERIFY_ID Class
Class = 10.
o C-Type = 1
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Verify_Id |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
J. Lang, Editor Standards Track [Page 54]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
Verify_Id: 32 bits
This is used to differentiate Test messages from different TE
links and/or LMP peers. This is a node-unique value that is
assigned by the recipient of the BeginVerify message.
This object is non-negotiable.
13.11. TE_LINK Class
Class = 11.
o C-Type = 1, IPv4 TE_LINK
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | (Reserved) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local_Link_Id (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Remote_Link_Id (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o C-Type = 2, IPv6 TE_LINK
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | (Reserved) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Local_Link_Id (16 bytes) +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Remote_Link_Id (16 bytes) +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o C-Type = 3, Unnumbered TE_LINK
J. Lang, Editor Standards Track [Page 55]
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | (Reserved) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local_Link_Id (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Remote_Link_Id (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Reserved field should be sent as zero and ignored on receipt.
Flags: 8 bits
The following flags are defined. All other values are reserved
and should be sent as zero and ignored on receipt.
0x01 Fault Management Supported.
0x02 Link Verification Supported.
Local_Link_Id:
This identifies the nodeÆs local Link_Id and MUST be non-zero.
Remote_Link_Id:
This identifies the remote nodeÆs Link_Id and MUST be non-zero.
13.12. DATA_LINK Class
Class = 12.
o C-Type = 1, IPv4 DATA_LINK
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | (Reserved) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local_Interface_Id (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Remote_Interface_Id (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// (Subobjects) //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o C-Type = 2, IPv6 DATA_LINK
J. Lang, Editor Standards Track [Page 56]
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | (Reserved) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Local_Interface_Id (16 bytes) +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Remote_Interface_Id (16 bytes) +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// (Subobjects) //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o C-Type = 3, Unnumbered DATA_LINK
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | (Reserved) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local_Interface_Id (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Remote_Interface_Id (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// (Subobjects) //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Reserved field should be sent as zero and ignored on receipt.
Flags: 8 bits
The following flags are defined. All other values are reserved
and should be sent as zero and ignored on receipt.
0x01 Interface Type: If set, the data link is a port,
otherwise it is a component link.
J. Lang, Editor Standards Track [Page 57]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
0x02 Allocated Link: If set, the data link is currently
allocated for user traffic. If a single
Interface_Id is used for both the
transmit and receive data links, then
this bit only applies to the transmit
interface.
0x04 Failed Link: If set, the data link is failed and not
suitable for user traffic.
Local_Interface_Id:
This is the local identifier of the data link. This MUST be
node-wide unique and non-zero.
Remote_Interface_Id:
This is the remote identifier of the data link. This MUST be
non-zero.
Subobjects
The contents of the DATA_LINK object consist of a series of
variable-length data items called subobjects. The subobjects
are defined in section 13.12.1 below.
A DATA_LINK object may contain more than one subobject. More than
one subobject of the same Type may appear if multiple capabilities
are supported over the data link.
13.12.1. Data Link Subobjects
The contents of the DATA_LINK object include a series of variable-
length data items called subobjects. Each subobject has the form:
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+---------------//------------ -+
| Type | Length | (Subobject contents) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--------------//---------------+
Type: 8 bits
The Type indicates the type of contents of the subobject.
Currently defined values are:
Type = 1, Interface Switching Capability
Type = 2, Wavelength
J. Lang, Editor Standards Track [Page 58]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
Length: 8 bits
The Length contains the total length of the subobject in bytes,
including the Type and Length fields. The Length MUST be at
least 4, and MUST be a multiple of 4.
13.12.1.1. Subobject Type 1: Interface Switching Capability
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Switching Cap | EncType |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Minimum Reservable Bandwidth |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Maximum Reservable Bandwidth |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Switching Capability: 8 bits
This is used to identify the local Interface Switching
Capability of the TE link as defined in [GMPLS-SIG].
EncType: 8 bits
This is the encoding type of the data link. The defined
EncType values are consistent with the Link Encoding Type
values of [GMPLS-SIG].
Minimum Reservable Bandwidth: 32 bits
This is measured in bytes per second and represented in IEEE
floating point format.
Maximum Reservable Bandwidth: 32 bits
This is measured in bytes per second and represented in IEEE
floating point format.
If the interface only supports a fixed rate, the minimum and maximum
bandwidth fields are set to the same value.
13.12.1.2. Subobject Type 2: Wavelength
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | (Reserved) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Wavelength |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
J. Lang, Editor Standards Track [Page 59]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
The Reserved field should be sent as zero and ignored on receipt.
Wavelength: 32 bits
This value indicates the wavelength carried over the port.
Values used in this field only have significance between two
neighbors.
13.13. CHANNEL_STATUS Class
Class = 13
o C-Type = 1, IPv4 INTERFACE_ID
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface_Id (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A|D| Channel Status |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| : |
// : //
| : |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface_Id (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A|D| Channel Status |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o C-Type = 2, IPv6 INTERFACE_ID
J. Lang, Editor Standards Track [Page 60]
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Interface_Id (16 bytes) +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A|D| Channel Status |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| : |
// : //
| : |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Interface_Id (16 bytes) +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A|D| Channel Status |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o C-Type = 3, Unnumbered INTERFACE_ID
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface_Id (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A|D| Channel Status |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| : |
// : //
| : |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface_Id (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A|D| Channel_Status |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Active bit: 1 bit
This indicates that the Channel is allocated to user traffic and the
data link should be actively monitored.
J. Lang, Editor Standards Track [Page 61]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
Direction bit: 1 bit
This indicates the direction (transmit/receive) of the data channel
referred to in the CHANNEL_STATUS object. If set, this indicates
the data channel is in the transmit direction.
Channel_Status: 30 bits
This indicates the status condition of a data channel. The
following values are defined. All other values are reserved
and should be sent as zero and ignored on receipt.
1 Signal Okay (OK): Channel is operational
2 Signal Degrade (SD): A soft failure caused by a BER
exceeding a preselected threshold. The specific
BER used to define the threshold is configured.
3 Signal Fail (SF): A hard signal failure including (but not
limited to) loss of signal (LOS), loss of frame
(LOF), or Line AIS.
This object contains one or more Interface_Ids followed by a
Channel_Status field.
To indicate the status of the entire TE Link, there MUST only be one
Interface_Id and it MUST be zero.
This object is non-negotiable.
13.14. CHANNEL_STATUS_REQUEST Class
Class = 14
o C-Type = 1, IPv4 INTERFACE_ID
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface_Id (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| : |
// : //
| : |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface_Id (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This object contains one or more Interface_Ids.
The Length of this object is 4 + 4N in bytes, where N is the number
of Interface_Ids.
o C-Type = 2, IPv6 INTERFACE_ID
J. Lang, Editor Standards Track [Page 62]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Interface_Id (16 bytes) +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| : |
// : //
| : |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Interface_Id (16 bytes) +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This object contains one or more Interface_Ids.
The Length of this object is 4 + 16N in bytes, where N is the number
of Interface_Ids.
o C-Type = 3, Unnumbered INTERFACE_ID
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface_Id (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| : |
// : //
| : |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface_Id (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This object contains one or more Interface_Ids.
The Length of this object is 4 + 4N in bytes, where N is the number
of Interface_Ids.
This object is non-negotiable.
J. Lang, Editor Standards Track [Page 63]
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13.15. ERROR_CODE Class
Class = 20.
o C-Type = 1, BEGIN_VERIFY_ERROR
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ERROR CODE |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The following bit-values are defined in network byte order
(i.e., big-endian byte order):
0x01 = Link Verification Procedure not supported.
0x02 = Unwilling to verify.
0x04 = Unsupported verification transport mechanism.
0x08 = Link_Id configuration error.
All other values are reserved and should be sent as zero and
ignored on receipt.
Multiple bits may be set to indicate multiple errors.
This object is non-negotiable.
If a BeginVerifyNack message is received with Error Code 2, the node
that originated the BeginVerify SHOULD schedule a BeginVerify
retransmission after Rf seconds, where Rf is a locally defined
parameter.
o C-Type = 2, LINK_SUMMARY_ERROR
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ERROR CODE |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The following bit-values are defined in network byte order
(i.e., big-endian byte order):
0x01 = Unacceptable non-negotiable LINK_SUMMARY parameters
0x02 = Renegotiate LINK_SUMMARY parameters
0x04 = Bad Received Remote_Link_Id
0x08 = Bad TE Link Object
0x10 = Bad Data Link Object
All other values are reserved and should be sent as zero and
ignored on receipt.
J. Lang, Editor Standards Track [Page 64]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
Multiple bits may be set to indicate multiple errors.
This object is non-negotiable.
14. Intellectual Property Considerations
The IETF takes no position regarding the validity or scope of any
intellectual property or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on the
IETF's procedures with respect to rights in standards-track and
standards-related documentation can be found in BCP-11. Copies of
claims of rights made available for publication and any assurances
of licenses to be made available, or the result of an attempt made
to obtain a general license or permission for the use of such
proprietary rights by implementers or users of this specification
can be obtained from the IETF Secretariat.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive
Director.
15. References
15.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[BUNDLE] Kompella, K., Rekhter, Y., Berger, L., "Link Bundling in
MPLS Traffic Engineering," (work in progress).
[GMPLS-SIG] Ashwood-Smith, P., Banerjee, A., et al, "Generalized
MPLS - Signaling Functional Description," (work in
progress).
[GMPLS-RTG] Kompella, K., Rekhter, Y. et al, "Routing Extensions in
Support of Generalized MPLS", (work in progress).
[RFC2961] Berger, L., Gan, D., et al, "RSVP Refresh Overhead
Reduction Extensions," RFC 2961, April 2001.
[RFC2402] Kent, S., Atkinson, R., "IP Authentication Header", RFC
2402, November 1998
[RFC2406] Kent, S., Atkinson, R., "IP Encapsulating Security
Payload (ESP)", RFC 2406, November 1998
[RFC2407] Piper, D., "The Internet IP Security Domain of
Interpretation for ISAKMP", RFC 2407, November 1998
[RFC2409] Harkins, D., Carrel, D., "The Internet Key Exchange
(IKE)", RFC 2409, November 1998
J. Lang, Editor Standards Track [Page 65]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
15.2. Informative References
[RFC3209] Awduche, D. O., Berger, L, et al, "Extensions to RSVP
for LSP Tunnels," Internet Draft, RFC3209 December 2001.
[OSPF-TE] Katz, D., Yeung, D., Kompella, K., "Traffic Engineering
Extensions to OSPF," (work in progress).
[ISIS-TE] Li, T., Smit, H., "IS-IS extensions for Traffic
Engineering," (work in progress).
[RFC2401] Kent, S., Atkinson, R., "Security Architecture for the
Internet Protocol", RFC 2401, November 1998
[RFC2434] Narten, T. and Alvestrand, H., "Guidelines for Writing
an IANA Considerations Section in RFCs," RFC 2434,
October 1998.
16. Security Considerations
There are number of attacks that an LMP protocol session can
potentially experience. Some examples include:
o an adversary may spoof control packets
o an adversary may modify the control packets in transit
o an adversary may replay control packets
o an adversary may study a number of control packets and try to
break the key using cryptographic tools. If the
hash/encryption algorithm used has known weaknesses than it
becomes easy for the adversary to discover the key using
simple tools.
This section specifies an IPsec-based security mechanism for LMP.
16.1. Security Requirements
The following requirements are applied to the mechanism described in
this section.
o LMP security MUST be able to provide authentication, integrity
and replay protection.
o For LMP traffic, confidentiality is not needed. Only
authentication is needed to ensure the control packets
(packets sent along the LMP Control Channel) are originating
from the right place and have not been modified in transit.
LMP Test packets exchanged through the data links do not need
to be protected.
o Security mechanism should provide for well defined key
management schemes. The key management schemes should be well
analyzed to be cryptographically secure. The key management
schemes should be scalable.
J. Lang, Editor Standards Track [Page 66]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
o The algorithms used for authentication MUST be
cryptographically sound. Also the security protocol MUST
allow for negotiating and using different authentication
algorithms.
16.2. Security Mechanisms
IPsec is a protocol suite that is used to secure communication at the
network layer between two peers. This protocol is comprised of IP
Security architecture document [RFC2401], IKE [RFC2409], IPsec AH
[RFC2402], and IPsec ESP [RFC2406]. IKE is the key management
protocol for IP networks while AH and ESP are used to protect IP
traffic. IKE is defined specific to IP domain of interpretation.
Considering the requirements described in Section 16.1, it is
recommended that where security is needed for LMP, implementations
use IPsec as described below:
1. IPsec AH, tunnel mode SHOULD be used for packet authentication.
2. IKE [RFC2409] SHOULD be used as the key exchange mechanism.
Implementations of LMP over IPsec protocol MUST support manual keying
mode and dynamic key exchange protocol using IKE. IKE implementation
SHOULD use the IPsec DOI [RFC2407].
For IKE protocol, the identities of the SAs negotiated in Quick Mode
represent the traffic that the peers agree to protect and are
comprised of address space, protocol and port information. For LMP
over IPsec, it is recommended that the identity payload contain the
following information. The identities SHOULD be of type IP
addresses and the value of the identities SHOULD be the IP addresses
of the communicating peers. The protocol field SHOULD be IP protocol
UDP (17). The port field SHOULD be set to zero to indicate port
fields should be ignored. In LMP exchanges, the channel identifier
user by the peer is not known beforehand, and hence cannot be used in
the SA. This restriction implies that LMP authentication is
performed on a per LMP neighbor basis rather than on a per LMP
control channel basis between two neighbors.
All LMP messages are expected to be sent over the IPsec channel. The
crypto channel (IKE SA and IPsec SAs) may be established on need
basis or earlier. However, all LMP messages should be sent through
the crypto channel.
A set of control channels can share the same crypto channel. When
LMP Hellos are used to monitor the status of the control channel, it
is important to keep in mind that the keep-alive failure in a control
channel may also be due to failure in the crypto channel. The
following method is recommended to ensure LMP communication path
between two peers is working properly.
J. Lang, Editor Standards Track [Page 67]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
- If LMP Hellos detect a failure on a control channel, switch to an
alternate (backup) control channel and/or try to bring up a new
control channel.
- Ensure the health of the control channels using LMP Hellos. If
all control channels indicate a failure and it is not possible to
bring up a new control channel, tear down all existing control
channels. Also tear down the crypto channel (both the IKE SA and
IPsec SAs).
- Reestablish the crypto channel. Failure to establish a crypto
channel indicates a fatal failure for LMP communication.
- Bring up the control channel. Failure to bring up the control
channel indicates a fatal failure for LMP communication.
o When LMP peers are dynamically discovered (particularly the
initiator), the following points should be noted if pre-shared
key based authentication is used for setting up the crypto
channels. When using pre-shared key based authentication, the
pre-shared key is required to compute the value of SKEYID
(used for deriving keys to encrypt messages during key
exchange). In main mode, pre-shared key to be used has to be
identified from information in the IP header since SKEYID is
calculated prior to the receipt of identification payloads.
This is not possible if the IP addresses of the peer are
discovered dynamically. Aggressive mode of key exchange can
be used since identification payloads are sent in the first
message.
Note however that aggressive mode is prone to passive denial of
service attacks. We also strongly discourage using a shared secret
(group shared secret) among a number of peers as this opens up the
solution to man-in-the middle attacks.
Digital signature based authentication is not prone to such problems.
It is recommended using digital signature based authentication
mechanism where possible. If pre-shared key based authentication is
required, then aggressive mode SHOULD be used. IKE pre-shared
authentication key values SHOULD be protected in a manner similar to
the user's account password.
17. IANA Considerations
LMP requires that a UDP port number be assigned.
LMP defines the following name spaces that require management:
- LMP Message Type.
- LMP Object Class.
J. Lang, Editor Standards Track [Page 68]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
- LMP Object Class type (C-Type). These are unique within the
Object Class.
- LMP Sub-object Class type (Type). These are unique within the
Object Class.
The LMP Message Type name space should be allocated as follows:
pursuant to the policies outlined in [RFC2434], the numbers in the
range 0-127 are allocated by Expert Review, 128-240 are allocated
through an IETF Consensus action, and 241-255 are reserved for
Private Use.
The LMP Object Class name space should be allocated as follows:
pursuant to the policies outlined in [RFC2434], the numbers in the
range of 0-127 are allocated by Expert Review, 128-247 are allocated
through an IETF Consensus action, and 248-255 are reserved for
Private Use.
The LMP Sub-object Class name space should be allocated as follows:
pursuant to the policies outlined in [RFC2434], the numbers in the
range of 0-127 are allocated by Expert Review, 128-247 are allocated
through an IETF Consensus action, and 248-255 are reserved for
Private Use.
The LMP Object Class type name space should be allocated as follows:
pursuant to the policies outlined in [RFC2434], the numbers in the
range 0-111 are allocated by Expert Review, 112-119 are allocated
through an IETF Consensus action, and 120-127 are reserved for
Private Use.
The following name spaces need to be assigned initially:
[Note to RFC Editor: Please drop all text enclosed in parentheses in
this section once the IANA assignments are made. The values are
included for reference only and should be considered unassigned.]
------------------------------------------------------------------
LMP Message Type name space
o Config message (suggested Message type = 1)
o ConfigAck message (suggested Message type = 2)
o ConfigNack message (suggested Message type = 3)
o Hello message (suggested Message type = 4)
o BeginVerify message (suggested Message type = 5)
o BeginVerifyAck message (suggested Message type = 6)
o BeginVerifyNack message (suggested Message type = 7)
J. Lang, Editor Standards Track [Page 69]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
o EndVerify message (suggested Message type = 8)
o EndVerifyAck message (suggested Message type = 9)
o Test message (suggested Message type = 10)
o TestStatusSuccess message (suggested Message type = 11)
o TestStatusFailure message (suggested Message type = 12)
o TestStatusAck message (suggested Message type = 13)
o LinkSummary message (suggested Message type = 14)
o LinkSummaryAck message (suggested Message type = 15)
o LinkSummaryNack message (suggested Message type = 16)
o ChannelStatus message (suggested Message type = 17)
o ChannelStatusAck message (suggested Message type = 18)
o ChannelStatusRequest message (suggested Message type = 19)
o ChannelStatusResponse message (suggested Message type = 20)
------------------------------------------------------------------
LMP Object Class name space and Class type (C-Type)
o CCID Class name (suggested = 1)
- LOCAL_CCID (suggested C-Type = 1)
- REMOTE_CCID (suggested C-Type = 2)
o NODE_ID Class name (suggested = 2)
- LOCAL_NODE_ID (suggested C-Type = 1)
- REMOTE_NODE_ID (suggested C-Type = 2)
o LINK_ID Class name (suggested = 3)
- IPv4 LOCAL_LINK_ID (suggested C-Type = 1)
- IPv4 REMOTE_LINK_ID (suggested C-Type = 2)
- IPv6 LOCAL_LINK_ID (suggested C-Type = 3)
- IPv6 REMOTE_LINK_ID (suggested C-Type = 4)
- unnumbered LOCAL_LINK_ID (suggested C-Type = 5)
- unnumbered REMOTE_LINK_ID (suggested C-Type = 6)
o INTERFACE_ID Class name (suggested = 4)
- IPv4 LOCAL_INTERFACE_ID (suggested C-Type = 1)
- IPv4 REMOTE_INTERFACE_ID (suggested C-Type = 2)
- IPv6 LOCAL_INTERFACE_ID (suggested C-Type = 3)
- IPv6 REMOTE_INTERFACE_ID (suggested C-Type = 4)
- unnumbered LOCAL_INTERFACE_ID (suggested C-Type = 5)
- unnumbered REMOTE_INTERFACE_ID (suggested C-Type = 6)
J. Lang, Editor Standards Track [Page 70]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
o MESSAGE_ID Class name (suggested = 5)
- MESSAGE_ID (suggested C-Type = 1)
- MESSAGE_ID_ACK (suggested C-Type = 2)
o CONFIG_ID Class name (suggested = 6)
- HELLO_CONFIG (suggested C-Type = 1)
o HELLO Class name (suggested = 7)
- HELLO (suggested C-Type = 1)
o BEGIN_VERIFY Class name (suggested = 8)
- Type 1 (suggested C-Type = 1)
o BEGIN_VERIFY_ACK Class name (suggested = 9)
- Type 1 (suggested C-Type = 1)
o VERIFY_ID Class name (suggested = 10)
- Type 1 (suggested C-Type = 1)
o TE_LINK_ID Class name (suggested = 11)
- IPv4 TE_LINK_ID (suggested C-Type = 1)
- IPv6 TE_LINK_ID (suggested C-Type = 2)
- unnumbered TE_LINK_ID (suggested C-Type = 3)
o DATA_LINK_ID Class name (suggested = 12)
- IPv4 DATA_LINK_ID (suggested C-Type = 1)
- IPv6 DATA_LINK_ID (suggested C-Type = 2)
- unnumbered DATA_LINK_ID (suggested C-Type = 3)
- Interface Switching Capability (suggested sub-object Type = 1)
- Wavelength (suggested sub-object Type = 2)
o CHANNEL_STATUS Class name (suggested = 13)
- IPv4 INTERFACE_ID (suggested C-Type = 1)
- IPv6 INTERFACE_ID (suggested C-Type = 2)
- unnumbered INTERFACE_ID (suggested C-Type = 3)
o CHANNEL_STATUS_REQUEST Class name (suggested = 14)
- IPv4 INTERFACE_ID (suggested C-Type = 1)
- IPv6 INTERFACE_ID (suggested C-Type = 2)
- unnumbered INTERFACE_ID (suggested C-Type = 3)
o ERROR_CODE Class name (suggested = 20)
- BEGIN_VERIFY_ERROR (suggested C-Type = 1)
- LINK_SUMMARY_ERROR (suggested C-Type = 2)
18. Acknowledgements
The authors would like to thank Andre Fredette for his many
contributions to this document. We would also like to thank Ayan
Banerjee, George Swallow, Andre Fredette, Adrian Farrel, Vinay
J. Lang, Editor Standards Track [Page 71]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
Ravuri, and David Drysdale for their insightful comments and
suggestions. We would also like to thank John Yu, Suresh Katukam,
and Greg Bernstein for their helpful suggestions for the in-band
control channel applicability. Finally, we would like to thank
Dimitri Papadimitriou for his contributions to the SONET/SDH test
procedures.
19. Contributors
Jonathan P. Lang Krishna Mitra
Calient Networks Calient Networks
25 Castilian Drive 5853 Rue Ferrari
Goleta, CA 93117 San Jose, CA 95138
Email: jplang@calient.net email: krishna@calient.net
John Drake Kireeti Kompella
Calient Networks Juniper Networks, Inc.
5853 Rue Ferrari 1194 North Mathilda Avenue
San Jose, CA 95138 Sunnyvale, CA 94089
email: jdrake@calient.net email: kireeti@juniper.net
Yakov Rekhter Lou Berger
Juniper Networks, Inc. Movaz Networks
1194 North Mathilda Avenue email: lberger@movaz.com
Sunnyvale, CA 94089
email: yakov@juniper.net
Debanjan Saha Debashis Basak
Tellium Optical Systems Accelight Networks
2 Crescent Place 70 Abele Road, Suite 1201
Oceanport, NJ 07757-0901 Bridgeville, PA 15017-3470
email: dsaha@tellium.com email: dbasak@accelight.com
Hal Sandick Alex Zinin
Shepard M.S. Alcatel
2401 Dakota Street email: zinin@psg.com
Durham, NC 27705
email: sandick@nc.rr.com
Bala Rajagopalan Sankar Ramamoorthi
Tellium Optical Systems Juniper Networks, Inc.
2 Crescent Place 1194 North Mathilda Avenue
Oceanport, NJ 07757-0901 Sunnyvale, CA 94089
email: braja@tellium.com email: sankarr@juniper.net
20. Contact Address
Jonathan P. Lang
Calient Networks
25 Castilian Drive
Goleta, CA 93117
Email: jplang@calient.net
J. Lang, Editor Standards Track [Page 72]
Internet Draft draft-ietf-ccamp-lmp-05.txt August 2002
21. Full Copyright Statement
Copyright (C) The Internet Society (2001). All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
J. Lang, Editor Standards Track [Page 73]
