Network Working Group Andre Fredette (Editor)
Internet Draft Jonathan Lang (Calient Networks) (Editor)
Expiration Date: August 2002
Osama Aboul-Magd (Nortel Networks)
S. Brorson (Axiowave Networks)
S. Dharanikota (Nayna Networks, Inc)
John Drake (Calient Networks)
David Drysdale (Data Connection)
W. L. Edwards (iLambda Networks)
Adrian Farrel (Movaz Networks)
R. Goyal (Axiowave Networks)
Hirokazu Ishimatsu (Japan Telecom)
Monika Jaeger (T-systems)
R. Krishnan (Axiowave Networks)
Raghu Mannam (Hitachi Telecom)
Eric Mannie (Ebone (GTS))
Dimitri Papadimitriou (Alcatel)
Vasant Sahay (Nortel Networks)
Jagan Shantigram (PhotonEx Corp.)
Ed Snyder (PhotonEx Corp.)
George Swallow (Cisco Systems)
G. Tumuluri (Calient Networks)
Y. Xue (UUNET/WorldCom)
Lucy Yong (Williams Communications)
J. Yu
February 2002
Link Management Protocol (LMP) for DWDM Optical Line Systems
draft-ietf-ccamp-lmp-wdm-00.txt
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026 [RFC2026].
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six
months and may be updated, replaced, or obsoleted by other documents
at any time. It is inappropriate to use Internet- Drafts as
reference material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
[Page 1]
Internet Draft draft-ietf-ccamp-lmp-wdm-00.txt February 2002
ABSTRACT
A suite of protocols is being developed in the IETF to allow
networks consisting of photonic switches (PXCs), optical
crossconnects (OXCs), routers, switches, DWDM optical line systems
(OLSs), and optical add-drop multiplexors (OADMs) to use an MPLS-
based control plane to dynamically provision resources and to
provide network survivability using protection and restoration
techniques. As part of this protocol suite, the Link Management
Protocol (LMP) [LMP] is defined to "maintain control channel
connectivity, verify component link connectivity, and isolate link,
fiber, or channel failures within the network." In it's present
form, [LMP] focuses on peer communications (eg. OXC-to-OXC). In
this document we propose extensions to LMP for use with OLSs. These
extensions are intended to satisfy the "Optical Link Interface
Requirements" described in [OLI].
CONTENTS
1. Introduction.......................................................3
2. Scope of LMP-WDM Protocol..........................................5
3. LMP Extensions for Optical Line Systems............................5
3.1. Control Channel Management.......................................6
3.2. Link Verification................................................6
3.3. Link Summarization...............................................6
3.3.1. Link Group ID..................................................7
3.3.2. Shared Risk Link Group Identifier (SRLG):......................8
3.3.3. Bit Error Rate (BER) Estimate..................................9
3.3.4. Optical Protection.............................................9
3.3.5. Total Span Length:............................................10
3.3.6. Administrative Group (Color)..................................10
3.4. Fault Management................................................10
3.4.1. LINK GROUP CHANNEL_STATUS Object..............................11
3.5. Alarm Management................................................12
3.6. Trace Monitoring................................................13
3.6.1. TraceMonitor Message (MsgType = TBD)..........................13
3.6.1.1. TRACE Object................................................13
3.6.2. TraceMonitorAck Message (MsgType = TBD).......................14
3.6.3. TraceMonitorNack Message (MsgType = TBD)......................14
3.6.3.1. ERROR_CODE Class............................................15
3.6.4. TraceMismatch Message (MsgType = TBD).........................15
3.6.5. TraceMismatchAck Message (MsgType = TBD)......................15
3.6.6. TraceReq Message (MsgType = TBD)..............................15
3.6.7. TraceReport Message (MsgType = TBD)...........................16
3.6.8. TraceReqNak Message (MsgType = TBD)...........................16
3.6.9. InsertTraceReq Message (MsgType = TBD)........................16
3.6.10. InsertTraceAck Message (MsgType = TBD).......................16
3.6.11. InsertTraceNack Message (MsgType = TBD)......................17
4. Security Considerations...........................................17
5. Work Items........................................................17
6. References........................................................18
7. Author's Addresses................................................19
[Page 2]
Internet Draft draft-ietf-ccamp-lmp-wdm-00.txt February 2002
1. Introduction
Future networks will consist of photonic switches (PXCs), optical
crossconnects (OXCs), routers, switches, DWDM optical line systems
(OLSs), and optical add-drop multiplexors (OADMs) that use the GMPLS
control plane to dynamically provision resources and to provide
network survivability using protection and restoration techniques.
A pair of nodes (e.g., a PXC and an OLS) may be connected by
thousands of fibers. Furthermore, multiple fibers and/or multiple
wavelengths may be combined into a single bundled link. [LMP]
Defines the Link Management Protocol (LMP) to "maintain control
channel connectivity, verify component link connectivity, and
isolate link, fiber, or channel failures within the network." In
it's present form, [LMP] focuses on peer communications (eg. OXC-to-
OXC) as illustrated in Figure 1. In this document, extensions to
LMP for use with OLSs are proposed. These extensions are intended
to satisfy the "Optical Link Interface Requirements" described in
[OLI]. It is assumed that the reader is familiar with LMP as
defined in [LMP].
+------+ +------+ +------+ +------+
| | ----- | | | | ----- | |
| OXC1 | ----- | OLS1 | ===== | OLS2 | ----- | OXC2 |
| | ----- | | | | ----- | |
+------+ +------+ +------+ +------+
^ ^
| |
+----------------------LMP----------------------+
Figure 1: Base LMP Model
A great deal of information about a link between two OXCs is known
by the OLS. Exposing this information to the control plane via LMP
can improve network usability by further reducing required manual
configuration and also by greatly enhancing fault detection and
recovery. Fault detection is particularly an issue when the network
is using all-optical photonic switches (PXC). Once a connection is
established, PXCs have only limited visibility into the health of
the connection. Even though the PXC is all-optical, long-haul OLSs
typically terminate channels electrically and regenerate them
optically, which presents an opportunity to monitor the health of a
channel between PXCs. LMP-WDM can then be used by the OLS to
provide this information to the PXC using LMP-WDM.
In addition to the link information known to the OLS that is
exchanged through LMP-WDM, some information known to the OXC may
also be exchanged with the OLS through LMP-WDM. This information is
useful for alarm management and link monitoring (i.e., trace
monitoring). Alarm management is important because the
administrative state of a connection, known to the OXC (e.g., this
information may be learned through the Admin Status object of GMPLS
signaling [GMPLS]), can be used to suppress spurious alarms. For
example, the OXC may know that a connection is ôupö, ôdownö, in a
[Page 3]
Internet Draft draft-ietf-ccamp-lmp-wdm-00.txt February 2002
ôtestingö mode, or being deleted (ôdeletion-in-progressö). The OXC
can use this information to inhibit alarm reporting from the OLS
when a connection is ôdownö, ôtestingö, or being deleted.
The model for extending LMP to OLSs is shown in Figure 2.
+------+ +------+ +------+ +------+
| | ----- | | | | ----- | |
| OXC1 | ----- | OLS1 | ===== | OLS2 | ----- | OXC2 |
| | ----- | | | | ----- | |
+------+ +------+ +------+ +------+
^ ^ ^ ^ ^ ^
| | | | | |
| +-----LMP-----+ +-----LMP----+ |
| |
+----------------------LMP----------------------+
Figure 2: Extended LMP Model
In this model, an OXC may have multiple LMP sessions corresponding
to multiple peering relationships. At each level, LMP provides link
management functionality (i.e., control channel management, physical
connectivity verification, link property correlation) for that
peering relationship. For example, the OXC-OXC LMP session in
Figure 2 can be used to build traffic-engineering (TE) links for
GMPLS signaling and routing, and are managed as described in [LMP].
At the transport level, the OXC-OLS LMP session (also shown in
Figure 2) is used to augment knowledge about the links between the
OXCs. The management of these LMP sessions is discussed in this
draft. It is important to note that an OXC may peer with one or more
OLSs and an OLS may peer with one or more OXCs.
Although there are many similarities between an OXC-OXC LMP session
and an OXC-OLS LMP session, particularly for control management and
link verification, there are some differences as well. These
differences can primarily be attributed to the nature of an OXC-OLS
link, and the purpose of OXC-OLS LMP sessions. As previously
mentioned, the OXC-OXC links can be used to provide the basis for
GMPLS signaling and routing at the optical layer. The information
exchanged over LMP-WDM sessions is used to augment knowledge about
the links between OXCs.
In order for the information exchanged over the OXC-OLS LMP sessions
to be used by the OXC-OXC session, the information must be
coordinated by the OXC. However, the two LMP sessions are run
independently and MUST be maintained separately. One critical
requirement when running an OXC-OLS LMP session is the ability of
the OLS to make a data link transparent when not doing the
verification procedure. This is because the same data link may be
verified between OXC-OLS and between OXC-OXC. The BeginVerify
procedure of [LMP] is used to coordinate the Test procedure (and
hence the transparency/opaqueness of the data links).
[Page 4]
Internet Draft draft-ietf-ccamp-lmp-wdm-00.txt February 2002
To maintain independence between the sessions, it MUST be possible
for the LMP sessions to come up in any order. In particular, it
MUST be possible for an OXC-OXC LMP session to come up without an
OXC-OLS LMP session being brought up, and vice-versa.
Additional details about the extensions required for LMP are
outlined in the next section.
2. Scope of LMP-WDM Protocol
This document focuses on extensions required for use with opaque
OLSs. In particular, this document is intended for use with OLSs
having SONET, SDH, and Ethernet user ports.
If multiplexing is performed by an OLS using LMP-WDM, it is assumed
that it is done in such a way that it is ôtransparentö to the OLS
clients. Otherwise, the OLS may be required to become actively
involved in connection establishment by running higher-layer GMPLS
protocols. In this case, the OLS would effectively be treated as
just another switch in the optical network. Such active OLS
involvement is beyond the scope of this document.
At the time of this writing, work is ongoing in the area of fully
transparent wavelength routing; however, it is premature to identify
the necessary characteristics to exchange. That said, the protocol
described in this document provides the necessary framework in which
to exchange additional information as it is deemed appropriate.
3. LMP Extensions for Optical Line Systems
As currently defined, LMP consists of four types of functions:
1. Control Channel Management
2. Link Verification
3. Link Summarization
4. Fault Management
All four functions are supported in LMP-WDM. Additionally, a trace
monitoring function is added. (Note: Other monitoring types will be
considered in a future release.)
In this document we follow the convention of [LMP] and use the term
"data link" to refer to either "component links" or "ports".
It is very important to understand the subtle distinctions between
the different types of links being considered in the extended LMP-
WDM. For example, in Figure 2 when OXC1 and OXC2 complete the
verify process, the links being verified are the end-to-end links
between the OXC's. It is the TE link composed of these "data links"
that are advertised in the routing protocols and used for the
purposes of connection setup. The verify procedure between OXC1 and
OLS1, on the other hand verifies the shorter link between these two
nodes. However, each of these shorter links is a segment of one of
[Page 5]
Internet Draft draft-ietf-ccamp-lmp-wdm-00.txt February 2002
the larger end-to-end links. The verify serves two functions: to
verify connectivity and exchange handles by which each data link is
referred. Furthermore, it is up to the OXC to correlate the handles
between the various LMP sessions.
Once a control channel has been established and the OXC-OLS
verification procedure has been completed successfully, the OXC and
OLS may exchange information regarding link configuration (i.e.,
using the LinkSummary exchange). An OXC may also receive
notification regarding the operational status from an OLS (i.e.,
using the ChannelStatus exchange).
In subsequent sections, specific additions are proposed to extend
LMP to work with OLSs.
3.1. Control Channel Management
As in [LMP], we do not specify the exact implementation of the
control channel; 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.
The control channel management for OXC-OLS links is the same as for
OXC-OXC links, as described in [LMP]. The ôLMP-WDM Supportö flag in
the LMP Common Header is used to indicate support for the objects
defined in this draft. This informs the receiving node that the
LMP-WDM extensions will be used for the session. If the LMP-WDM
extensions are not supported by the node, it MUST reply to the
Config Message with a ConfigNack Message.
3.2. Link Verification
The Test procedure used with OLSs is the same as described in [LMP].
The VerifyTransportMechanism (included in the BeginVerify and
BeginVerifyAck messages) is used to allow nodes to negotiate a link
verification method and is essential for transmission systems which
have access to overhead bytes rather than the payload. The VerifyId
(provided by the remote node in the BeginVerifyAck message, and used
in all subsequent Test messages) is used to differentiate Test
messages from different LMP sessions.
3.3. Link Summarization
As in [LMP], the LinkSummary message is used to synchronize the
Interface Ids and correlate the properties of the TE link. (Note
that the term æTE LinkÆ originated from routing/signaling
applications of LMP, whereas this concept doesnÆt necessarily apply
to an OLS. However, the term is used in this draft to remain
consistent with LMP terminology.) Additional Data Link sub-objects
are defined in this draft to extend the LinkSummary message to
include additional link characteristics. These sub-objects are
described in the following subsections. The link characteristics,
in general, are those characteristics needed by the control plane
for constraint-based routing in the selection of a path for a
particular connection.
[Page 6]
Internet Draft draft-ietf-ccamp-lmp-wdm-00.txt February 2002
The format of the Data Link Sub-Objects follows the format described
in [LMP] and is shown below for readability:
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+---------------//--------------+
| Type | Length | (Sub-object contents) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+---------------//--------------+
Type: 8 bits
The Type indicates the type of contents of the subobject.
Length: 8 bits
The Length field contains the total length of the sub-object in
bytes, including the Type and Length fields. The Length MUST
be at least 4, and MUST be a multiple of 4.
The following Link Characteristics are advertised on a per data link
basis.
3.3.1. Link Group ID
The main purpose of the Link Group ID is to reduce control traffic
during failures that affect many data links. A local ID may be
assigned to a group of data links. This ID can be used to reduce
the control traffic in the case of a failure by enabling the systems
to send a single message for a group instead of individual messages
for each member of the group. A link may be a member of multiple
groups. This is achieved by presenting multiple Link Group ID
Objects in the LinkSummary message.
The Link Group ID feature allows Link Groups to be assigned based
upon the types of fault correlation and aggregation supported by a
given OLS. From a practical perspective, the Link Group ID is used
to map (or group) data links into "failable entities" known only to
the OLS. If one of those failable entities fails, all associated
data links are failed and the OXC may be notified with a single
message.
For example, an OLS could create a Link Group for each laser in the
OLS. This group could be associated with data links during
discovery/initialization time. Multiple data links could be
associated with a single group (depending on the kind of
multiplexing supported in the system). If a laser fails, the OLS
can report a failure for the group. The OXC that receives the group
failure message can determine the associated link or links. Another
group could be assigned for a fiber to report all data links down
that are associated with that fiber if LOS is detected at the fiber
level. Depending on the physical OLS implementation, it may make
sense to allocate other groups, such as all data links on a
particular circuit card. With this method, the OXC only needs to
know about the externally visible data links. The OLS can associate
[Page 7]
Internet Draft draft-ietf-ccamp-lmp-wdm-00.txt February 2002
the data links with logical groups and the OXC doesn't need to know
anything about the physical OLS implementation or how data links are
multiplexed electrically or optically within the system.
The format of the Link Group ID sub-object (Type=TBD, Length=8) 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Link Group ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link Group ID (cont) | (Reserved) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Link Group ID: 32 bits
Link Group ID 0xFFFFFFFF is reserved and indicates all data links
in a TE link. All data links are members of Link Group 0xFFFFFFFF
by default.
Reserved: 16 bits
Must be set to zero on transmit and ignored on receive.
3.3.2. Shared Risk Link Group Identifier (SRLG):
SRLGs of which the data link is a member. This information is
manually configured on an OLS by the user and may be used for
diverse path computation.
The format of the SRLG sub-object (Type=TBD) 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | SRLG value #1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SRLG value #1(cont) | SRLG value #2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ............ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SRLG value #(N-1)(cont) | SRLG value #N |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SRLG value #N(cont) | (Reserved) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Length: 8 bits
The length is (N+1)*4, where N is the number of SRLG values.
Shared Risk Link Group Value: 32 bits
List as many SRLGs as apply.
[Page 8]
Internet Draft draft-ietf-ccamp-lmp-wdm-00.txt February 2002
Reserved: 16 bits
Must be set to zero on transmit and ignored on receive.
3.3.3. Bit Error Rate (BER) Estimate
This Object provides an estimate of the BER for the data link.
The bit error rate (BER) is the proportion of bits that have errors
relative to the total number of bits received in a transmission,
usually expressed as ten to a negative power. For example, a
transmission might have a BER of "10 to the minus 13", meaning that,
out of every 10,000,000,000,000 bits transmitted, one bit may be in
error. The BER is an indication of overall signal quality.
The format of the BER Estimate subobject (Type=TBD; Length=4) 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | BER | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
BER: 8 bits
The exponent from the BER representation described above. For
example, if the BER is 10 to the minus X, the BER field is set to
X.
Reserved: 8 bits
Must be set to zero on transmit and ignored on receive.
3.3.4. Optical Protection
Whether the OLS protects the link internally. This information can
be used as a measure of quality of the link. It may be advertised
by routing and used by signaling as a selection criterion as
described in [GMPLS].
The format of the Optical Protection subobject (Type=TBD; Length=4)
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Link Flags| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Link Flags: 6 bits
Encoding for Link Flags can be found in [GMPLS].
[Page 9]
Internet Draft draft-ietf-ccamp-lmp-wdm-00.txt February 2002
Reserved: 10 bits
Must be set to zero on transmit and ignored on receive.
3.3.5. Total Span Length:
The total distance of fiber in OLS. May be used as a routing metric
or to estimate delay.
The format of the Span Length sub-object (Type=TBD, Length=8) 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Span Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Span Length (cont) | (Reserved) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Span Length: 32 bits
Total Length of the WDM span in meters expressed as an unsigned
integer.
Reserved: 16 bits
Must be set to zero on transmit and ignored on receive.
3.3.6. Administrative Group (Color)
The administrative group (or Color) to which the data link belongs.
The format of the Administrative Group sub-object (Type=TBD,
Length=8) 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Administrative Group |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Administrative Group (cont) | (Reserved) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Administrative Group: 32 bits
A 32 bit value.
Reserved: 16 bits
Must be set to zero on transmit and ignored on receive.
3.4. Fault Management
Fault management consists of three major functions:
[Page 10]
Internet Draft draft-ietf-ccamp-lmp-wdm-00.txt February 2002
1. Fault Detection
2. Fault Localization
3. Fault Notification
The actual Fault Detection mechanisms are the responsibility of the
individual nodes and are not specified as part of this protocol.
Fault detection mechanisms may include such things as bit error rate
(BER) exceeding a threshold, loss of signal (LOS) and SONET/SDH-
level errors. It is the responsibility of the OLS to translate
these failures into OK, SF, or SD as described in LMP.
Running LMP-WDM on the OLS allows the OLS to notify an attached OXC
or router when it detects a fault. The OXCs and routers continue to
execute the fault localization procedure as currently specified in
[LMP]. The main enhancement when using LMP-WDM is that the OLS may
initiate the process (both downstream and upstream). It is
important to note that the OLS does not participate in end-to-end
fault localization as described in [LMP].
The OLS may also execute its own fault localization process that may
allow it to determine the location of the fault much more
specifically than the OXCs can. For example, the OLS may be able to
pinpoint the fault to a particular amplifier along a set of fibers
that can span 1000's of kilometers.
To report data link failures and recovery conditions, LMP-WDM uses
the ChannelStatus, ChannelStatusAck, ChannelStatusRequest, and
ChannelStatusResponse Messages defined in [LMP].
Each data link is identified by an Interface_ID. In addition, LMP-
WDM specifies a Link Group_ID that may be assigned to a group of
data links (see Section 3.3.1). The Link Group ID may be used to
reduce the control traffic by providing channel status information
for a group of data links. A new LINK GROUP_CHANNEL STATUS object is
defined below for this purpose. This object may be used in place of
the CHANNEL_STATUS objects described in [LMP] in the ChannelStatus
message.
3.4.1. LINK GROUP CHANNEL_STATUS Object
The LINK GROUP_STATUS object is used to indicate the status of the
data links belonging to a particular Link Group. The correlation of
data links to Group ID is made with the Link Group ID subobject of
the DATA_LINK Object.
The format of the LINK GROUP_CHANNEL STATUS object is as follows
(Class = 18, C-Type to be assigned by IANA):
[Page 11]
Internet Draft draft-ietf-ccamp-lmp-wdm-00.txt February 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|N| C-Type | Class | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link Group_ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Channel_Status |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| : |
// : //
| : |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link Group ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Channel Status |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Link Group_ID: 32 bits
Link Group ID 0xFFFFFFFF is reserved and indicates all data links
in a TE link. All data links are members of Link Group 0xFFFFFFFF
by default.
Channel_Status: 32 bits
The values for the Channel_Status field are defined in [LMP].
This Object is non-negotiable.
3.5. Alarm Management
Alarm management is an important feature of LMP-WDM because it can
be used to suppress cascading and/or spurious alarms during normal
connection procedures. For example, the OXC may know that a
connection is ôupö, ôdownö, in a ôtestingö mode, or being deleted
(ôdeletion-in-progressö). The OXC can use this information to
inhibit alarm reporting from the OLS when the state of a connection
changes in a controlled fashion.
Alarm management is controlled using the Active bit of the
CHANNEL_STATUS object (see [LMP]).
In the following, we describe how the Active bit can be used in
conjunction with the Admin Status object of [GMPLS] to manage alarms
during graceful connection deletion.
Consider the network of Figure 3 where a wavelength LSP has been
established using RSVP-GMPLS from OXC-A through OXC-B to OXC-C. To
support graceful deletion of the LSP, the Deletion in Progress bit
is set in the Admin Status object of a Path message that is
transmitted from OXC-A through OXC-B to OXC-C. This bit indicates
that ôlocal actions related to LSP teardown should be taken.ö As
part of the local actions for LSP teardown, each OXC should notify
[Page 12]
Internet Draft draft-ietf-ccamp-lmp-wdm-00.txt February 2002
itÆs neighboring OLS(s) that the data link is now deactive. For
example, OXC-B should notify OLS-B1 and OLS-B2 that the link is
deactive before forwarding the Path message to the next node. This
ensures that when the connection is removed multiple alarms are not
triggered at each of the line systems.
+-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+
| OXC |---| OLS | | OLS |---| OXC |---| OLS | | OLS |---| OXC |
| A |---| A1 |===| B1 |---| B |---| B2 |===| C1 |---| C |
| |---| | | |---| |---| | | |---| |
+-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+
| | ^ ^ ||| ^ ^ | |
| +--------+ +--------+|+--------+ +--------+ |
| LMP-WDM LMP-WDM | LMP-WDM LMP-WDM |
+-------------------------------+------------------------------+
GMPLS Signaling GMPLS Signaling
Figure 3: Alarm Management Example
3.6. Trace Monitoring
The trace monitoring features described in this section allow a PXC
to do basic trace monitoring on circuits by using the capabilities
on an attached OLS.
. An OLS Client may request the OLS to monitor a link for a
specific pattern in the overhead using the TraceMonitorReq
Message. An example of this overhead is the SONET Section
Trace message transmitted in the J0 byte. If the actual trace
message does not match the expected trace message, the OLS MUST
report the mismatch condition.
. An OLS client may request the value of the current trace
message on a given data link using the TraceReq Message.
3.6.1. TraceMonitor Message (MsgType = TBD)
The TraceMonitor message is sent over the control channel and is
used to request an OLS to monitor a data link for a specific trace
value. An OLS MUST respond to a TraceMonitor message with either a
TraceMonitorAck or TraceMonitorNack Message.
<TraceMonitor Message> ::= <Common Header> <MESSAGE_ID>
<LOCAL_INTERFACE_ID> <TRACE>
If supported by the hardware, traces of different types may be
monitored simultaneously (e.g., Section and Path trace messages may
exist simultaneously on the same data link).
3.6.1.1. TRACE Object
The format of the TRACE object is as follows (Class and C-Type to be
assigned by IANA):
[Page 13]
Internet Draft draft-ietf-ccamp-lmp-wdm-00.txt February 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|N| C-Type | Class | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Trace Type | Trace Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// Trace Message //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Trace Object is non-negotiable.
Trace Type: 16 bits
The type of the trace message:
1 û SONET Section Trace (J0 Byte)
2 û SONET Path Trace (J1 Byte)
3 û SDH Section Trace (J0 Byte)
4 û SDH Path Trace (J1 Byte)
Other types TBD.
Trace Length: 16 bits
The Length in bytes of the trace message provided.
Trace Message:
Expected message. The valid length and value combinations are
determined by the specific technology (e.g., SONET or SDH) and
are beyond the scope of this document. The message MUST be
padded with zeros to a 32-bit boundary, if necessary.
3.6.2. TraceMonitorAck Message (MsgType = TBD)
The TraceMonitorAck message is used to indicate that all of the
Trace Objects in the TraceMonitor message have been received and
processed correctly.
The format is as follows:
<TraceMonitorAck Message> ::= <Common Header> <MESSAGE_ID_ACK>
The MESSAGE_ID_ACK object is defined in [LMP].
3.6.3. TraceMonitorNack Message (MsgType = TBD)
The TraceMonitorNack message is used to indicate that the Trace
Object in the TraceMonitor message was not processed correctly.
This could be because the trace monitoring requested is not
supported or there was an error in the value.
The format is as follows:
[Page 14]
Internet Draft draft-ietf-ccamp-lmp-wdm-00.txt February 2002
<TraceMonitorNack Message> ::= <Common Header> <MESSAGE_ID_ACK>
<ERROR_CODE>
The MESSAGE_ID_ACK object is defined in [LMP].
The TraceMonitorNack message uses the ERROR_CODE C-Type,
3.6.3.1. ERROR_CODE Class
C-Type = 20 (see [LMP])
LMP-WDM defines the following new error code bit-values:
TBD1 = Unsupported Trace Type
TBD2 = Invalid Trace Message
All other values are Reserved.
Multiple bits may be set to indicate multiple errors.
This Object is non-negotiable.
3.6.4. TraceMismatch Message (MsgType = TBD)
The TraceMismatch message is sent over the control channel and is
used to report a trace mismatch on a data link for which trace
monitoring was requested.
A neighboring node that receives a TraceMismatch message MUST
respond with a TraceMismatchAck message. The format is as follows:
<TraceMismatch Message> ::= <Common Header> <MESSAGE_ID>
<LOCAL_INTERFACE_ID> [<LOCAL_INTERFACE_ID> ...]
The LOCAL_INTERFACE_ID object is defined in [LMP]. The
LOCAL_INTERFACE_ID in this message is the local Interface Id of the
link that has a trace mismatch. A trace mismatch for multiple
LOCAL_INTERFACE_ID's may be reported in the same message.
3.6.5. TraceMismatchAck Message (MsgType = TBD)
The TraceMismatchAck message is used to acknowledge receipt of a
TraceMismatch message.
The format is as follows:
<TraceMismatchAck Message> ::= <Common Header> <MESSAGE_ID_ACK>
The MESSAGE_ID_ACK object is defined in [LMP] and must be copied
from the TraceMismatch Message being acknowledged.
3.6.6. TraceReq Message (MsgType = TBD)
The TraceReq message is sent over the control channel and is used to
request the current trace value of indicated data links.
[Page 15]
Internet Draft draft-ietf-ccamp-lmp-wdm-00.txt February 2002
A node that receives a TraceReq message MUST respond with a
TraceReport message. The format is as follows:
<TraceReq Message> ::= <Common Header> <MESSAGE_ID>
<LOCAL_INTERFACE_ID> <TRACE REQ>
The format of the TRACE_REQ 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Trace Type | (Reserved) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Trace Type: Defined in Section 3.6.1.1.
3.6.7. TraceReport Message (MsgType = TBD)
The TraceReport message is sent over the control channel after
receiving a TraceReq message.
<TraceReport Message> ::= <Common Header> <MESSAGE_ID_ACK> <TRACE>
The TraceReport message MUST include a TRACE Object (as described in
Section 3.6.1.1) for the link requested.
3.6.8. TraceReqNak Message (MsgType = TBD)
The TraceReqNak message is sent over the control channel after
receiving a TraceReq message.
<TraceReqNak Message> ::= <Common Header> <MESSAGE_ID_ACK>
<ERROR_CODE>
The TraceReqNak message MUST include an ERROR_CODE Object (as
described in Section 3.6.3) for the link requested.
3.6.9. InsertTraceReq Message (MsgType = TBD)
The InsertTraceReq message is sent over the control channel and is
used to request an OLS to send a specific trace message on a data
link. An OLS MUST respond to a InsertTraceReq message with either a
InsertTraceAck or InsertTraceNak Message.
<InsertTraceReq Message> ::= <Common Header> <MESSAGE_ID>
<LOCAL_INTERFACE_ID> <TRACE>
3.6.10. InsertTraceAck Message (MsgType = TBD)
The InsertTraceAck message is used to indicate that the TRACE Object
in the InsertTrace message has been received and processed
correctly.
[Page 16]
Internet Draft draft-ietf-ccamp-lmp-wdm-00.txt February 2002
The format is as follows:
<InsertTraceAck Message> ::= <Common Header> <MESSAGE_ID_ACK>
The MESSAGE_ID_ACK object is defined in [LMP].
3.6.11. InsertTraceNack Message (MsgType = TBD)
The InsertTraceNack message is used to indicate that the Trace
Object in the InsertTrace message was not processed correctly. This
could be because the trace monitoring requested is not supported or
there was an error in the value.
The format is as follows:
<InsertTraceNack Message> ::= <Common Header> <MESSAGE_ID_ACK>
<ERROR_CODE>
The MESSAGE_ID_ACK object is defined in [LMP]. The ERROR_CODE
Object usage is described in Section 3.6.3.1.
4. Security Considerations
General LMP security issues are discussed in [LMP]. As in [LMP],
LMP-WDM exchanges may be authenticated using the Cryptographic
authentication option. MD5 is currently the only message digest
algorithm specified. The InsertTraceReq and TraceMonitor messages
introduced in this document present an opportunity for an intruder
to disrupt transmission. Authentication of messages is recommended
if the control network itself is not secure.
5. Work Items
The following work items have been identified. They will be
addressed in a future version of this draft:
1. Error messages may be needed in response to some of the defined
messages.
2. Provide description of procedures and interactions for running
LMP and LMP-WDM on the same link. Include description of how
control over link transparency works during the Verify
procedure.
3. Determine whether some functions are optional and, if so,
provide a capability negotiation mechanism.
[Page 17]
Internet Draft draft-ietf-ccamp-lmp-wdm-00.txt February 2002
6. References
[GMPLS] Berger, L., Ashwood-Smith, Peter, editors,
"Generalized MPLS - Signaling Functional Description",
Internet Draft, draft-ietf-mpls-generalized-signaling-
02.txt, (work in progress), March 2001.
[Bra96] Bradner, S., "The Internet Standards Process --
Revision 3," BCP 9, RFC 2026, October 1996.
[DBC00] Drake, J., Blumenthal, D., Ceuppens, L., et al.,
"Interworking between Photonic (Optical) Switches and
Transmission Systems over Optical Link Interface (OLI)
using Extensions to LMP", OIF Contribution
oif2000.254, (work in progress), November 2000.
[KRB00] Kompella, K., Rekhter, Y., Berger, L., "Link Bundling
in MPLS Traffic Engineering," Internet Draft, draft-
kompella-mpls-bundle-02.txt, (work in progress), July
2000.
[KRB00a] Kompella, K., Rekhter, Y., Banerjee, A., et al, "OSPF
Extensions in Support of Generalized MPLS," Internet
Draft, draft-kompella-ospf-extensions-00.txt, (work in
progress), July 2000.
[LMP] Lang, J., Mitra, K., Drake, J., Kompella, K., Rekhter,
Y., Berger, L., Saha, D., Basak, D., Sandick, H.,
Zinin, A., "Link Management Protocol (LMP)", Internet
Draft, draft-ietf-ccamp-lmp-02.txt, (work in
progress), July 2001.
[OLI] Fredette, A., Editor, "Optical Link Interface
Requirements", Internet Draft, draft-many-oli-reqts-
00.txt, (work in progress), June 2001.
[SDH] ITU-T G.707, "Network node interface for the
synchronous digital hierarchy (SDH)", 1996.
[SONET] GR-253-CORE, "Synchronous Optical Network (SONET)
Transport Systems: Common Generic Criteria", Telcordia
Technologies, Issue 3, September 2000
[T.50] ITU-T T.50, "International Reference Alphabet (IRA)
(formerly International Alphabet No. 5 or IA5)
Information technology 7-bit coded character set for
information interchange.", 1992.
[Page 18]
Internet Draft draft-ietf-ccamp-lmp-wdm-00.txt February 2002
7. Author's Addresses
Osama S. Aboul-Magd Rohit Goyal
Nortel Networks Axiowave Networks
P.O. Box 3511, Station C 100 Nickerson Road
Ottawa, Ontario, Canada Marlborough, MA 01752
K1Y 4H7 email: rgoyal@axiowave.com
Phone: 613-763-5827
email: osama@nortelnetworks.com Hirokazu Ishimatsu
Japan Telecom
Stuart Brorson 2-9-1 Hatchobori. Chuo-ku,
Axiowave Networks Tokyo, 104-0032 Japan
100 Nickerson Road email: hirokazu@japan-
Marlborough, MA 01752 telecom.co.jp
email: sdb@axiowave.com
Monika Jaeger
Sudheer Dharanikota T-systems
Nayna Networks, Inc. Monika.Jaeger@t-systems.de
157 Topaz Drive,
Milpitas, CA 95035 Ram Krishnan
email: sudheer@nayna.com Axiowave Networks
100 Nickerson Road
John Drake Marlborough, MA 01752
Calient Networks email: ram@axiowave.com
5853 Rue Ferrari
San Jose, CA 95138 Jonathan P. Lang
email: jdrake@calient.net Calient Networks
Court25 Castilian Drive
David Drysdale Goleta, CA 93117
Data Connection Ltd email: jplang@calient.net
dmd@dataconnection.com
Raghu Mannam
W. L. Edwards Hitachi Telecom (USA), Inc.
iLambda Networks rmannam@hitel.com
Aspen, CO
email: texas@ilambda.com Eric Mannie
Ebone (GTS)
Adrian Farrel (Movaz Networks) Terhulpsesteenweg 6A
Movaz Networks, Inc. 1560 Hoeilaart
7926 Jones Branch Drive, Belgium
Suite 615 Email: eric.mannie@gts.com
McLean, VA 22102
email: afarrel@movaz.com Dimitri Papadimitriou
Alcatel
Andre Fredette Francis Wellesplein 1,
email: afredette@charter.net B-2018 Antwerpen, Belgium
email: dimitri.Papadimitriou
@alcatel.be
[Page 19]
Internet Draft draft-ietf-ccamp-lmp-wdm-00.txt February 2002
Jagan Shantigram Yong Xue
PhotonEx Corporation UUNET/WorldCom
8C Preston 22001 Loudoun County Parkway
Bedford, MA 01730 Ashburn, VA 20148
email: jagan@photonex.com email: yxue@uu.net
Ed Snyder Lucy Yong
PhotonEx Corporation Williams Communications
8C Preston Court 2 East First Street
Bedford, MA 01730 Tulsa, OK 74172
email: esnyder@photonex.com lucy.yong@wilcom.com
George Swallow John Yu
Cisco Systems, Inc. Zaffire, Inc
250 Apollo Drive 2630 Orchard Parkway
Chelmsford, MA 01824 San Jose, CA 95134
Email: swallow@cisco.com email: jzyu@zaffire.com
Gopala Tumuluri
Calient Networks
5853 Rue Ferrari
San Jose, CA 95138
email: krishna@calient.net
[Page 20]
