draft-ietf-mpls-cr-ldp-01.txt   draft-ietf-mpls-cr-ldp-02.txt 
MPLS WG Bilel Jamoussi, Editor
MPLS Working Group Bilel Jamoussi, Editor Internet Draft Nortel Networks Corp.
Internet Draft Nortel Networks Expiration Date: February 2000
Expiration Date: August 1999 August 1999
February 1999
Constraint-Based LSP Setup using LDP Constraint-Based LSP Setup using LDP
draft-ietf-mpls-cr-ldp-01.txt draft-ietf-mpls-cr-ldp-02.txt
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026. all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six
and may be updated, replaced, or obsoleted by other documents at any months and may be updated, replaced, or obsoleted by other documents
time. It is inappropriate to use Internet- Drafts as reference at any time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as _work in progress._
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (1998). All Rights Reserved.
Abstract Abstract
Label Distribution Protocol (LDP) is defined in [LDP] for Label Distribution Protocol (LDP) is defined in [1] for distribution
distribution of labels inside one MPLS domain. One of the most of labels inside one MPLS domain. One of the most important
important services that may be offered using MPLS in general and LDP services that may be offered using MPLS in general and LDP in
in particular is support for constraint-based routing of traffic particular is support for constraint-based routing of traffic across
across the routed network. Constraint-based routing offers the the routed network. Constraint-based routing offers the opportunity
opportunity to extend the information used to setup paths beyond what to extend the information used to setup paths beyond what is
is available for the routing protocol. For instance, an LSP can be available for the routing protocol. For instance, an LSP can be
setup based on explicit route constraints, QoS constraints, and setup based on explicit route constraints, QoS constraints, and
others. Constraint-based routing (CR) is a mechanism used to meet other constraints. Constraint-based routing (CR) is a mechanism used
Traffic Engineering requirements that have been proposed by [FRAME], to meet Traffic Engineering requirements that have been proposed by
[ARCH] and [TER]. These requirements may be met by extending LDP for [2], [3] and [4]. These requirements may be met by extending LDP for
support of constraint-based routed label switched paths (CRLSPs). support of constraint-based routed label switched paths (CRLSPs).
Other uses exist for CRLSPs as well ([5], [6] and [7]).
CR-LDP Specification - 2 - Exp. August 1999
Other uses exist for CRLSPs as well ([VPN1], [VPN2] and [VPN3]).
This draft specifies mechanisms and TLVs for support of CRLSPs using This draft specifies mechanisms and TLVs for support of CRLSPs using
LDP. The Explicit Route object and procedures are extracted from LDP. The Explicit Route object and procedures are extracted from
[ER]. [8].
Table of Contents Table of Contents
1. Introduction ......................................... 3 Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 1 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
2. Constraint-based Routing Overview .................... 3
2.1 Strict and Loose Explicit Routes ..................... 4
2.2 Traffic Characteristics .............................. 4
2.3 Pre-emption .......................................... 5
2.4 Route Pinning ........................................ 5
2.5 Resource Class ....................................... 5
3. Solution Overview .................................... 5
3.1 Required Messages and TLVs ........................... 7
3.2 Label Request Message ................................ 7
3.3 Label Mapping Message ................................ 8
3.4 Notification Message ................................. 9
3.5 Release & Withdraw Messages .......................... 9
4. Protocol Specification .............................. 9
4.1 Explicit Route TLV (ER-TLV) ......................... 10
4.2 Explicit Route Hop TLV .............................. 10
4.3 Traffic Parameters TLV .............................. 12
4.3.1 Semantics ........................................... 13
4.3.1.1 Frequency ........................................... 13
4.3.1.2 Peak Rate ........................................... 14
4.3.1.3 Committed Rate ...................................... 14
4.3.1.4 Excess Burst Size .................................... 14
4.3.1.5 Peak Rate Token Bucket................................ 14
4.3.1.6 Committed Data Rate Token Bucket ..................... 15
4.3.1.7 Weight ......................... ..................... 16
4.3.2 Procedures ........................................... 16
4.3.2.1 Label Request Message ................................ 16
4.3.2.2 Label Mapping Message ................................ 16
4.3.2.3 Notification Message ................................. 17
4.4 Preemption TLV ....................................... 18
4.5 LSPID TLV ........................................... 18
4.6 Resource Class TLV .................................. 19
4.7 ER-Hop Semantics ..................................... 19
4.7.1 ER-Hop 1 TLV IPv4 Prefix ............................. 20
4.7.2 ER-Hop 2 TLV IPv6 Prefix ............................. 20
4.7.3 ER-Hop 3 TLV AS Number ............................... 21
4.7.4 ER-Hop 4 TLV LSPID ................................... 21
4.8 Processing of the ER-TLV ............................. 22
4.8.1 Selection of the next hop ............................ 22
4.8.2 Adding the Label Request Message to the next hop ..... 24
4.9 Route Pinning TLV ................................... 24
4.10 CR-LSP FEC Element ................................... 24
4.11 Error Subcodes ...................................... 25
CR-LDP Specification - 3 - Exp. August 1999
5. Security Considerations .............................. 26 1. Introduction....................................................3
6. Acknowledgement ...................................... 26 2. Constraint-based Routing Overview...............................3
7. References ........................................... 26 2.1 Strict and Loose Explicit Routes...............................3
8. Author Information ................................... 28 2.2 Traffic Characteristics........................................4
2.3 Pre-emption....................................................4
2.4 Route Pinning..................................................5
2.5 Resource Class.................................................5
3. Solution Overview...............................................5
3.1 Required Messages and TLVs.....................................6
3.2 Label Request Message..........................................7
3.3 Label Mapping Message..........................................7
3.4 Notification Message...........................................8
3.5 Release , Withdraw, and Abort Messages.........................9
4. Protocol Specification..........................................9
4.1 Explicit Route TLV (ER-TLV)....................................9
4.2 Explicit Route Hop TLV (ER-Hop TLV)...........................10
4.3 Traffic Parameters TLV........................................11
4.3.1 Semantics...................................................13
4.3.1.1 Frequency.................................................13
4.3.1.2 Peak Rate.................................................13
4.3.1.3 Committed Rate............................................13
4.3.1.4 Excess Burst Size.........................................14
4.3.1.5 Peak Rate Token Bucket....................................14
4.3.1.6 Committed Data Rate Token Bucket..........................14
4.3.1.7 Weight....................................................15
4.3.2 Procedures..................................................15
4.3.2.1 Label Request Message.....................................15
4.3.2.2 Label Mapping Message.....................................16
4.3.2.3 Notification Message......................................16
4.4 Preemption TLV................................................16
4.5 LSPID TLV.....................................................17
4.6 Resource Class (Color) TLV....................................18
4.7 ER-Hop semantics..............................................19
4.7.1. ER-Hop 1: The IPv4 prefix..................................19
4.7.2. ER-Hop 2: The IPv6 address.................................19
4.7.3. ER-Hop 3: The autonomous system number....................20
4.7.4. ER-Hop 4: LSPID............................................20
4.8. Processing of the Explicit Route TLV.........................22
4.8.1. Selection of the next hop..................................22
4.8.2. Adding ER-Hops to the explicit route TLV...................23
4.9 Route Pinning TLV.............................................23
4.10 CRLSP FEC Element............................................24
4.11 Error subcodes...............................................24
5. Security.......................................................25
6. Acknowledgments................................................25
7. Intellectual Property Consideration............................25
8. References.....................................................25
9. Author's Addresses.............................................26
Appendix A: CRLSP Establishment Examples..........................29
A.1 Strict Explicit Route Example.................................29
A.2. Node Groups and Specific Nodes Example.......................30
Appendix A CRLSP Establishment Examples ......................... 30 Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 2 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
A.1 Strict Explicit Route Example ........................ 30
A.2 Node Groups and Specific Nodes Example ............... 31
Appendix B QoS Service Examples ................................. 34 Appendix B. QoS Service Examples..................................33
B.1 Service Examples ..................................... 34 B.1 Service Examples..............................................33
B.2 Establishing CR-LSP Supporting Real-Time Applications. 35 B.2. Establishing CR-LSP Supporting Real-Time Applications........34
B.3 Establishing CR-LSP Delay Insensitive Applications ... 36 B.3. Establishing CR-LSP Supporting Delay Insensitive Applications35
1. Introduction 1. Introduction
The need for constraint-based routing (CR) in MPLS has been explored The need for constraint-based routing (CR) in MPLS has been explored
elsewhere [ARCH], [FRAME], and [TER]. Explicit routing is a subset elsewhere [3], [2], and [4]. Explicit routing is a subset of the
of the more general constraint-based routing function. At the MPLS WG more general constraint-based routing function. At the MPLS WG
meeting held during the Washington IETF there was consensus that LDP meeting held during the Washington IETF (December 1997) there was
should support explicit routing of LSPs with provision for indication consensus that LDP should support explicit routing of LSPs with
of associated (forwarding) priority. In the Chicago meeting, a provision for indication of associated (forwarding) priority. In
decision was made that support for explicit path setup in LDP will be the Chicago meeting (August 1998), a decision was made that support
moved to a separate document. This document provides that support and for explicit path setup in LDP will be moved to a separate document.
it has been accepted as a working document in the Orlando meeting. This document provides that support and it has been accepted as a
working document in the Orlando meeting (December 1998).
This specification proposes an end-to-end setup mechanism of a This specification proposes an end-to-end setup mechanism of a
constraint-based routed LSP (CRLSP) initiated by the ingress LSR. We constraint-based routed LSP (CRLSP) initiated by the ingress LSR. We
also specify mechanisms to provide means for reservation of resources also specify mechanisms to provide means for reservation of
using LDP. resources using LDP.
This document introduce TLVs and procedures that provide support for:
This document introduce TLVs and procedures that provide support
for:
- Strict and Loose Explicit Routing - Strict and Loose Explicit Routing
- Specification of Traffic Parameters - Specification of Traffic Parameters
- Route Pinning - Route Pinning
- CRLSP Pre-emption though setup/holding priorities - CRLSP Pre-emption though setup/holding priorities
- Handling Failures - Handling Failures
- LSPID - LSPID
- Resource Class - Resource Class
Section 2 introduces the various constraints defined in this Section 2 introduces the various constraints defined in this
specification. Section 3 outlines the CR-LDP solution. Section 4 specification. Section 3 outlines the CR-LDP solution. Section 4
defines the TLVs and procedures used to setup constraint-based routed defines the TLVs and procedures used to setup constraint-based
label switched paths. Appendix A provides several examples of CR-LSP routed label switched paths. Appendix A provides several examples
path setup. Appendix B provides Service Definition Examples. of CR-LSP path setup. Appendix B provides Service Definition
Examples.
2. Constraint-based Routing Overview 2. Constraint-based Routing Overview
Constraint-based routing is a mechanism that supports the Traffic Constraint-based routing is a mechanism that supports the Traffic
Engineering requirements defined in [TER]. Explicit Routing is a Engineering requirements defined in [4]. Explicit Routing is a
subset of the more general constraint-based routing where the subset of the more general constraint-based routing where the
CR-LDP Specification - 4 - Exp. August 1999
constraint is the explicit route (ER). Other constraints are defined constraint is the explicit route (ER). Other constraints are defined
to provide a network operator with control over the path taken by an to provide a network operator with control over the path taken by an
LSP. This section is an overview of the various constraints supported LSP. This section is an overview of the various constraints
by this specification. supported by this specification.
2.1 Strict and Loose Explicit Routes 2.1 Strict and Loose Explicit Routes
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 3 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
Like any other LSP an CRLSP is a path through an MPLS network. The Like any other LSP an CRLSP is a path through an MPLS network. The
difference is that while other paths are setup solely based on difference is that while other paths are setup solely based on
information in routing tables or from a management system, the information in routing tables or from a management system, the
constraint-based route is calculated at one point at the edge of constraint-based route is calculated at one point at the edge of
network based on criteria, including but not limited to routing network based on criteria, including but not limited to routing
information. The intention is that this functionality shall give information. The intention is that this functionality shall give
desired special characteristics to the LSP in order to better support desired special characteristics to the LSP in order to better
the traffic sent over the LSP. The reason for setting up CRLSPs, support the traffic sent over the LSP. The reason for setting up
might be that one wants to assign certain bandwidth or other Service CRLSPs, might be that one wants to assign certain bandwidth or other
Class characteristics to the LSP, or that one wants to make sure that Service Class characteristics to the LSP, or that one wants to make
alternative routes use physically separate paths through the network. sure that alternative routes use physically separate paths through
the network.
An explicit route is represented in a Label Request Message as a An explicit route is represented in a Label Request Message as a
list of nodes or groups of nodes along the constraint-based route. list of nodes or groups of nodes along the constraint-based route.
When the CRLSP is established, all or a subset of the nodes in a When the CRLSP is established, all or a subset of the nodes in a
group may be traversed by the LSP. Certain operations to be group may be traversed by the LSP. Certain operations to be
performed along the path can also be encoded in the constraint-based performed along the path can also be encoded in the constraint-based
route. route.
The capability to specify, in addition to specified nodes, groups of The capability to specify, in addition to specified nodes, groups of
nodes, of which a subset will be traversed by the CRLSP, allows the nodes, of which a subset will be traversed by the CRLSP, allows the
system a significant amount of local flexibility in fulfilling a system a significant amount of local flexibility in fulfilling a
request for a constraint-based route. This allows the generator of request for a constraint-based route. This allows the generator of
the constraint-based route to have some degree of imperfect the constraint-based route to have some degree of imperfect
information about the details of the path. information about the details of the path.
The constraint-based route is encoded as a series of ER-Hops The constraint-based route is encoded as a series of ER-Hops
contained in a constraint-based route TLV. Each ER-Hop may identify contained in a constraint-based route TLV. Each ER-Hop may identify
a group of nodes in the constraint-based route. A constraint-based a group of nodes in the constraint-based route. A constraint-based
route is then a path including all of the identified groups of nodes. route is then a path including all of the identified groups of
nodes.
To simplify the discussion, we call each group of nodes an abstract To simplify the discussion, we call each group of nodes an abstract
node. Thus, we can also say that a constraint-based route is a path node. Thus, we can also say that a constraint-based route is a path
including all of the abstract nodes, with the specified operations including all of the abstract nodes, with the specified operations
occurring along that path. occurring along that path.
2.2 Traffic Characteristics 2.2 Traffic Characteristics
The traffic characteristics of a path are described in the Traffic The traffic characteristics of a path are described in the Traffic
Parameters TLV in terms of a peak rate, committed rate, and service Parameters TLV in terms of a peak rate, committed rate, and service
granularity. The peak and committed rates describe the bandwidth granularity. The peak and committed rates describe the bandwidth
constraints of a path while the service granularity can be used to constraints of a path while the service granularity can be used to
specify a constraint on the delay variation that the CRLDP MPLS specify a constraint on the delay variation that the CRLDP MPLS
domain may introduce to a path's traffic. domain may introduce to a path's traffic.
CR-LDP Specification - 5 - Exp. August 1999
2.3 Pre-emption 2.3 Pre-emption
CR-LDP signals the resources required by a path on each hop of the CR-LDP signals the resources required by a path on each hop of the
route. If a route with sufficient resources can not be found, route. If a route with sufficient resources can not be found,
existing paths may be rerouted to reallocate resources to the new existing paths may be rerouted to reallocate resources to the new
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 4 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
path. This is the process of path pre-emption. Setup and holding path. This is the process of path pre-emption. Setup and holding
priorities are used to rank existing paths (holding priority) and the priorities are used to rank existing paths (holding priority) and
new path (setup priority) to determine if the new path can pre-empt the new path (setup priority) to determine if the new path can pre-
an existing path. empt an existing path.
The setupPriority of a new CRLSP and the holdingPriority attributes The setupPriority of a new CRLSP and the holdingPriority attributes
of the existing CRLSP are used to specify priorities. Signaling a of the existing CRLSP are used to specify priorities. Signaling a
higher holding priority expresses that the path, once it has been higher holding priority express that the path, once it has been
established, should have a lower chance of being pre-empted. established, should have a lower chance of being pre-empted.
Signaling a higher setup priority expresses the expectation that, in Signaling a higher setup priority expresses the expectation that, in
the case that resource are unavailable, the path is more likely to the case that resource are unavailable, the path is more likely to
pre-empt other paths. The exact rules determining bumping are an pre-empt other paths. The exact rules determining bumping are an
aspect of network policy. aspect of network policy.
The allocation of setup and holding priority values to paths is an The allocation of setup and holding priority values to paths is an
aspect of network policy. aspect of network policy.
The setup and holding priority values range from zero (0) to seven The setup and holding priority values range from zero (0) to seven
(7). The value zero (0) is the priority assigned to the most (7). The value zero (0) is the priority assigned to the most
important path. It is referred to as the highest priority. Seven (7) important path. It is referred to as the highest priority. Seven (7)
is the priority for the least important path. The use of default is the priority for the least important path. The use of default
priority values is an aspect of network policy. priority values is an aspect of network policy.
The setupPriority of a CRLSP should not be higher (numerically less) The setupPriority of a CRLSP should not be higher (numerically less)
than its holdingPriority since it might bump an LSP and be bumped by than its holdingPriority since it might bump an LSP and be bumped by
next "equivalent" request. next _equivalent_ request.
2.4 Route Pinning 2.4 Route Pinning
Route pinning is applicable to segments of an LSP that are loosely Route pinning is applicable to segments of an LSP that are loosely
routed - i.e. those segments which are specified with a next hop with routed - i.e. those segments which are specified with a next hop
the 'L' bit set or where the next hop is an "abstract node". A CRLSP with the `L' bit set or where the next hop is an _abstract node_. A
may be setup using route pinning if it is undesirable to change the CRLSP may be setup using route pinning if it is undesirable to
path used by an LSP because a better next hop becomes available at change the path used by an LSP because a better next hop becomes
some LSR along the loosely routed portion of the LSP. available at some LSR along the loosely routed portion of the LSP.
2.5 Resource Class 2.5 Resource Class
Network resources may be classified in various ways by the network The network operator may classify network resources in various ways.
operator. These classes are also known as "colors" or "administrative These classes are also known as _colors_ or _administrative groups_.
groups". When an CR-LSP is being established, it's necessary to When an CR-LSP is being established, it's necessary to indicate
indicate which resource classes the CR-LSP can draw from. which resource classes the CR-LSP can draw from.
3. Solution Overview 3. Solution Overview
CRLSP over LDP Specification is designed with the following goals: CRLSP over LDP Specification is designed with the following goals:
CR-LDP Specification - 6 - Exp. August 1999 1. Meet the requirements outlined in [4] for performing traffic
engineering and provide a solid foundation for performing
more general constraint-based routing.
1. Meet the requirements outlined in [TER] for performing traffic Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 5 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
engineering and provide a solid foundation for performing more
general constraint-based routing.
2. Build on already specified functionality that meets the 2. Build on already specified functionality that meets the
requirements whenever possible. Hence, this specifications is requirements whenever possible. Hence, this specification is
based on [LDP] and the Explicit Route object and procedures based on [1] and the Explicit Route object and procedures
defined in [ER]. defined in [8].
3. Keep the solution simple. 3. Keep the solution simple.
In this document, support for unidirectional point-to-point CRLSPs is In this document, support for unidirectional point-to-point CRLSPs
specified. Support for point-to-multipoint, multipoint-to-point, is is specified. Support for point-to-multipoint, multipoint-to-point,
for further study (FFS). is for further study (FFS).
Support for constraint-based routed LSPs in this specification Support for constraint-based routed LSPs in this specification
depends on the following minimal LDP behaviors as specified in [LDP]: depends on the following minimal LDP behaviors as specified in [1]:
- Basic and/or Extended Discovery Mechanisms. - Basic and/or Extended Discovery Mechanisms.
- Use the Label Request Message defined in [1] in downstream on
- Use the Label Request Message defined in [LDP] in downstream on
demand label advertisement mode with ordered control. demand label advertisement mode with ordered control.
- Use the Label Mapping Message defined in [1] in downstream on
- Use the Label Mapping Message defined in [LDP] in downstream on
demand mode with ordered control. demand mode with ordered control.
- Use the Notification Message defined in [1].
- Use the Notification Message defined in [LDP]. - Use the Withdraw and Release Messages defined in [1].
- Use the Withdraw and Release Messages defined in [LDP].
- Use the Loop Detection (in the case of loosely routed segments - Use the Loop Detection (in the case of loosely routed segments
of a CRLSP) mechanisms defined in [LDP]. of a CRLSP) mechanisms defined in [1].
In addition, the following functionality is added to what's defined In addition, the following functionality is added to what's defined
in [LDP]: in [1]:
- The Label Request Message used to setup a CRLSP includes one or - The Label Request Message used to setup a CRLSP includes one or
more CR-TLVs defined in Section 4. For instance, the Label Request more CR-TLVs defined in Section 4. For instance, the Label
Message may include the ER-TLV. Request Message may include the ER-TLV.
- An LSR implicitly infers ordered control from the existence of - An LSR implicitly infers ordered control from the existence of
one or more CR-TLVs in the Label Request Message. This means that one or more CR-TLVs in the Label Request Message. This means
the LSR can still be configured for independent control for LSPs that the LSR can still be configured for independent control
established as a result of dynamic routing. However, when a Label for LSPs established as a result of dynamic routing. However,
Request Message includes one or more of the CR-TLVs, then ordered when a Label Request Message includes one or more of the CR-
control is used to setup the CRLSP. Note that this is also true TLVs, then ordered control is used to setup the CRLSP. Note
for the loosely routed parts of a CRLSP. that this is also true for the loosely routed parts of a CRLSP.
- New status codes are defined to handle error notification for - New status codes are defined to handle error notification for
failure of established paths specified in the CR-TLV. failure of established paths specified in the CR-TLV.
CR-LDP Specification - 7 - Exp. August 1999 Optional TLVs are not required in the CR-LDP messages for the
messages to be compliant with the protocol. Optional parameters CAN
be required for a particular operation to work (or work correctly),
however.
Examples of CRLSP establishment are given in Appendix A to illustrate Examples of CRLSP establishment are given in Appendix A to
how the mechanisms described in this draft work. illustrate how the mechanisms described in this draft work.
3.1 Required Messages and TLVs 3.1 Required Messages and TLVs
Any Messages, TLVs, and procedures not defined explicitly in this Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 6 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
document are defined in the [LDP] Specification. The state
transitions which relate to CR-LDP messages can be found in [LDP-
STATE].
The following subsections are meant as a cross reference to the [LDP] Any Messages, TLVs, and procedures not defined explicitly in this
document are defined in the LDP Specification [1]. The state
transitions, which relate to CR-LDP messages, can be found in [9].
The following subsections are meant as a cross-reference to the [1]
document and indication of additional functionality beyond what's document and indication of additional functionality beyond what's
defined in [LDP] where necessary. defined in [1] where necessary.
3.2 Label Request Message 3.2 Label Request Message
The Label Request Message is as defined in 3.5.8 of [LDP] with the The Label Request Message is as defined in 3.5.8 of [1] with the
following modifications (required only if any of the CR-TLVs is following modifications (required only if any of the CR-TLVs is
included in the Label Request Message): included in the Label Request Message):
- Only a single FEC-TLV may be included in the Label Request - Only a single FEC-TLV may be included in the Label Request
Message. The CR-LSP FEC TLV should be used. Message. The CR-LSP FEC TLV should be used.
- The Return Message ID TLV is MANDATORY.
- The Optional Parameters TLV includes the definition of any of - The Optional Parameters TLV includes the definition of any of
the Constraint-based TLVs specified in Section 4. the Constraint-based TLVs specified in Section 4.
- The Procedures to handle the Label Request Message are augmented - The Procedures to handle the Label Request Message are
by the procedures for processing of the CR-TLVs as defined in augmented by the procedures for processing of the CR-TLVs as
Section 4. defined in Section 4.
The encoding for the CR-LDP Label Request Message is as follows: The encoding for the CR-LDP Label Request Message is as follows:
CR-LDP Specification - 8 - Exp. August 1999
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U| Label Request (0x0401) | Message Length | |0| Label Request (0x0401) | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID | | Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FEC TLV | | FEC TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Return Message ID TLV (mandatory) | | Message ID TLV (mandatory) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LSPID TLV (CR-LDP, mandatory) | | LSPID TLV (CR-LDP, mandatory) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ER-TLV (CR-LDP, optional) | | ER-TLV (CR-LDP, optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Traffic TLV (CR-LDP, optional) | | Traffic TLV (CR-LDP, optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Pinning TLV (CR-LDP, optional) | | Pinning TLV (CR-LDP, optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Resource Class TLV (CR-LDP, optional) | | Resource Class TLV (CR-LDP, optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Pre-emption TLV (CR-LDP, optional) | | Pre-emption TLV (CR-LDP, optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.3 Label Mapping Message 3.3 Label Mapping Message
The Label Mapping Message is as defined in 3.5.7 of [LDP] with the Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 7 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
The Label Mapping Message is as defined in 3.5.7 of [1] with the
following modifications: following modifications:
- Only a single Label-TLV may be included in the Label Mapping - Only a single Label-TLV may be included in the Label Mapping
Message. Message.
- The Label Mapping Message MUST include Label Request Message ID
TLV.
- The Label Mapping Message MUST include LSPID TLV.
- The Label Mapping Message Procedures are limited to downstream - The Label Mapping Message Procedures are limited to downstream
on demand ordered control mode. on demand ordered control mode.
A Mapping message is transmitted by a downstream LSR to an upstream A Mapping message is transmitted by a downstream LSR to an upstream
LSR under one of the following conditions: LSR under one of the following conditions:
1. The LSR is the egress end of the CRLSP and an upstream mapping 1. The LSR is the egress end of the CRLSP and an upstream
has been requested. mapping has been requested.
2. The LSR received a mapping from its downstream next hop LSR for 2. The LSR received a mapping from its downstream next hop LSR
an CRLSP for which an upstream request is still pending. for an CRLSP for which an upstream request is still pending.
The encoding for the CR-LDP Label Mapping Message is as follows: The encoding for the CR-LDP Label Mapping Message is as follows:
CR-LDP Specification - 9 - Exp. August 1999
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U| Label Mapping (0x0400) | Message Length | |0| Label Mapping (0x0400) | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID | | Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FEC TLV | | FEC TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label TLV | | Label TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label Request Message ID TLV (mandatory) | | Label Request Message ID TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LSPID TLV (CR-LDP, mandatory) | | LSPID TLV (CR-LDP, optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Traffic TLV (CR-LDP, optional) | | Traffic TLV (CR-LDP, optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.4 Notification Message 3.4 Notification Message
The Notification Message is as defined in Section 3.5.1 of [LDP] and The Notification Message is as defined in Section 3.5.1 of [1] and
the Status TLV encoding is as defined in Section 3.4.7 of [LDP]. the Status TLV encoding is as defined in Section 3.4.7 of [1].
Establishment of an Explicitly Routed LSP may fail for a variety of Establishment of an Explicitly Routed LSP may fail for a variety of
reasons. All such failures are considered advisory conditions and reasons. All such failures are considered advisory conditions and
they are signaled by the Notification Message. they are signaled by the Notification Message.
Notification Messages carry Status TLVs to specify events being Notification Messages carry Status TLVs to specify events being
signaled. New status codes are defined in Section 4.11 to signal signaled. New status codes are defined in Section 4.11 to signal
error notifications associated with the establishment of a CRLSP and error notifications associated with the establishment of a CRLSP and
the processing of the CR-TLV. the processing of the CR-TLV.
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 8 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
The Notification Message must carry the LSPID TLV of the The Notification Message must carry the LSPID TLV of the
corresponding CRLSP. corresponding CRLSP.
3.5 Release and Withdraw Messages Notification Messages MUST be forwarded toward the LSR originating
the Label Request at each hop and at any time that procedures in
this specification - or in [1] - specify sending of a Notification
Message in response to a Label Request Message.
The Label Release and Label Withdraw Messages are used as specified The encoding of the notification message is as follows:
in [LDP] to clear CR-LSPs. These message may also carry the LSPID
TLV. 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| Notification (0x0001) | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Status (TLV) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Optional Parameters |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.5 Release , Withdraw, and Abort Messages
The Label Release , Label Withdraw, and Label Abort Request Messages
are used as specified in [1]. These messages may also carry the
LSPID TLV.
4. Protocol Specification 4. Protocol Specification
The Label Request Messages defined in [LDP] optionally carries one or The Label Request Messages defined in [1] optionally carries one or
more of the optional Constraint-based Routing TLVs (CR-TLVs) defined more of the optional Constraint-based Routing TLVs (CR-TLVs) defined
in this section. If needed, other constraints can be supported later in this section. If needed, other constraints can be supported later
through the definition of new TLVs. In this specification, the through the definition of new TLVs. In this specification, the
following TLVs are defined: following TLVs are defined:
- Explicit Route TLV - Explicit Route TLV
CR-LDP Specification - 10 - Exp. August 1999
- Explicit Route Hop TLV - Explicit Route Hop TLV
- Traffic Parameters TLV - Traffic Parameters TLV
- Preemption TLV - Preemption TLV
- LSPID TLV - LSPID TLV
- Route Pinning TLV - Route Pinning TLV
- Resource Class TLV - Resource Class TLV
- CRLSP FEC TLV - CRLSP FEC TLV
4.1 Explicit Route TLV (ER-TLV) 4.1 Explicit Route TLV (ER-TLV)
The ER-TLV is an object that specifies the path to be taken by the The ER-TLV is an object that specifies the path to be taken by the
LSP being established. It is composed of one or more Explicit Route LSP being established. It is composed of one or more Explicit Route
Hop TLVs (ER-Hop TLVs) defined in Section 4.2. Hop TLVs (ER-Hop TLVs) defined in Section 4.2.
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 9 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| ER-TLV (0x0800) | Length | |0|0| ER-TLV (0x0800) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ER-Hop TLV 1 | | ER-Hop TLV 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ER-Hop TLV 2 | | ER-Hop TLV 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ ............ ~ ~ ............ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ER-Hop TLV n | | ER-Hop TLV n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
U bit
Unknown TLV bit. As defined in [LDP].
F bit
Forward unknown TLV bit. As defined in [LDP].
Type Type
A two byte field carrying the value of the ER-TLV type which A two-byte field carrying the value of the ER-TLV type whichis
is 0x800. 0x800.
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes.
ER-Hop TLVs ER-Hop TLVs
One or more ER-Hop TLVs defined in Section 4.2. One or more ER-Hop TLVs defined in Section 4.2.
4.2 Explicit Route Hop TLV (ER-Hop TLV) 4.2 Explicit Route Hop TLV (ER-Hop TLV)
The contents of an ER-TLV are a series of variable length ER-Hop The contents of an ER-TLV are a series of variable length ER-Hop
TLVs. Each ER-Hop TLV has the form: TLVs.
CR-LDP Specification - 11 - Exp. August 1999 A node receiving a label request message including an ER-Hop type
that is not supported should not progress the label request message
to the downstream LSR and should send back a _No Route_ Notification
Message.
Each ER-Hop TLV has the form:
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| ER-Hop-Type | Length | |0|0| ER-Hop-Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Content // | |L| Content // |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
U bit
Unknown TLV bit. As defined in [LDP].
F bit
Forward unknown TLV bit. As defined in [LDP].
ER-Hop Type ER-Hop Type
A fourteen-bit field indicating the type of contents of A fourteen-bit field indicating the type of contents of the ER-
the ER-Hop. Currently defined values are: Hop. Currently defined values are:
Value Type Value Type
----- ------------------------ ----- ------------------------
0x801 IPv4 prefix 0x801 IPv4 prefix
0x802 IPv6 prefix 0x802 IPv6 prefix
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 10 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
0x803 Autonomous system number 0x803 Autonomous system number
0x804 LSPID 0x804 LSPID
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes.
L bit L bit
The L bit is an attribute of the ER-Hop. The L bit is set if the The L bit is an attribute of the ER-Hop. The L bit is set if
ER-Hop represents a loose hop in the explicit route. If the bit is the ER-Hop ER-Hop represents a loose hop in the explicit route.
not set, the ER-Hop represents a strict hop in the explicit route. If the bit is not set, the ER-Hop represents a strict hop in
the explicit route.
The L bit in the ER-Hop is a one-bit attribute. If the L bit is
set, then the value of the attribute is "loose." Otherwise, the
value of the attribute is "strict." For brevity, we say that if
the value of the ER-Hop attribute is loose then it is a "loose
ER-Hop." Otherwise, it's a "strict ER-Hop." Further, we say that
the abstract node of a strict or loose ER-Hop is a strict or a
loose node, respectively. Loose and strict nodes are always
interpreted relative to their prior abstract nodes.
The L bit in the ER-Hop is a one-bit attribute. If the L bit
is set, then the value of the attribute is _loose._ Otherwise,
the value of the attribute is _strict._ For brevity, we say
that if the value of the ER-Hop attribute is loose then it is a
_loose ER-Hop._ Otherwise, it's a _strict ER-Hop._ Further,
we say that the abstract node of a strict or loose ER-Hop is a
strict or a loose node, respectively. Loose and strict nodes
are always interpreted relative to their prior abstract nodes.
The path between a strict node and its prior node MUST include The path between a strict node and its prior node MUST include
only network nodes from the strict node and its prior abstract only network nodes from the strict node and its prior abstract
node. node.
The path between a loose node and its prior node MAY include other The path between a loose node and its prior node MAY include
network nodes which are not part of the strict node or its prior other network nodes, which are not part of the strict node or
abstract node. its prior abstract node.
CR-LDP Specification - 12 - Exp. August 1999
Contents Contents
A variable length field containing the node or abstract node that A variable length field containing the node or abstract node
is the consecutive nodes that make up the explicit routed LSP. that is the consecutive nodes that make up the explicit routed
LSP.
4.3 Traffic Parameters TLV 4.3 Traffic Parameters TLV
The following sections describe the CRLSP Traffic Parameters. The The following sections describe the CRLSP Traffic Parameters. The
required characteristics of a CRLSP are expressed by the Traffic required characteristics of a CRLSP are expressed by the Traffic
Parameter values. Parameter values.
A Traffic Parameters TLV, is used to signal the Traffic Parameter A Traffic Parameters TLV, is used to signal the Traffic Parameter
values. The Traffic Parameters are defined in the subsequent values. The Traffic Parameters are defined in the subsequent
sections. sections.
The Traffic Parameters TLV contains a Flags field, a Frequency, a The Traffic Parameters TLV contains a Flags field, a Frequency, a
Weight, and the five Traffic Parameters PDR, PBS, CDR, CBS, EBS. The Weight, and the five Traffic Parameters PDR, PBS, CDR, CBS, EBS.
Traffic Parameters TLV is shown below: The Traffic Parameters TLV is shown below:
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 11 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| Traf. Param. TLV (0x0810)| Length | |0|0| Traf. Param. TLV (0x0810)| Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Frequency | Reserved | Weight | | Flags | Frequency | Reserved | Weight |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Peak Data Rate (PDR) | | Peak Data Rate (PDR) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Peak Burst Size (PBS) | | Peak Burst Size (PBS) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Committed Data Rate (CDR) | | Committed Data Rate (CDR) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Committed Burst Size (CBS) | | Committed Burst Size (CBS) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Excess Burst Size (EBS) | | Excess Burst Size (EBS) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
U bit
Unknown TLV bit. As defined in [LDP].
F bit
Forward unknown TLV bit. As defined in [LDP].
Type Type
A fourteen-bit field carrying the value of the ER-TLV type which A fourteen-bit field carrying the value of the ER-TLV type
is 0x810. which is 0x810.
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes.
Flags Flags
The Flags field is shown below: The Flags field is shown below:
CR-LDP Specification - 13 - Exp. August 1999
+--+--+--+--+--+--+--+--+ +--+--+--+--+--+--+--+--+
| Res |F6|F5|F4|F3|F2|F1| | Res |F6|F5|F4|F3|F2|F1|
+--+--+--+--+--+--+--+--+ +--+--+--+--+--+--+--+--+
Res - These bits are reserved. Res - These bits are reserved.
Zero on transmission. Zero on transmission.
Ignored on receipt. Ignored on receipt.
F1 - Corresponds to the PDR. F1 - Corresponds to the PDR.
F2 - Corresponds to the PBS. F2 - Corresponds to the PBS.
F3 - Corresponds to the CDR. F3 - Corresponds to the CDR.
skipping to change at page 13, line 31 skipping to change at line 640
Each flag Fi is a Negotiable Flag corresponding to a Traffic Each flag Fi is a Negotiable Flag corresponding to a Traffic
Parameter. The Negotiable Flag value zero denotes NotNegotiable Parameter. The Negotiable Flag value zero denotes NotNegotiable
and value one denotes Negotiable. and value one denotes Negotiable.
Frequency Frequency
The Frequency field is coded as an 8 bit unsigned integer with The Frequency field is coded as an 8 bit unsigned integer with
the following code points defined: the following code points defined:
0 - Unspecified 0 - Unspecified
1 - Frequent 1 - Frequent
2 - VeryFrequest
3-255 - Reserved
Reserved Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 12 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
2- VeryFrequest 3-255 - Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
Weight Weight
An 8 bit unsigned integer indicating the weight of the CRLSP. An 8 bit unsigned integer indicating the weight of the CRLSP.
Valid weight values are from 1 to 255. The value 0 means Valid weight values are from 1 to 255. The value 0 means that
that weight is not applicable for the CRLSP. weight is not applicable for the CRLSP.
Traffic Parameters Traffic Parameters
Each Traffic Parameter is encoded as a 32 bit IEEE single- Each Traffic Parameter is encoded as a 32-bit IEEE single-
precision floating point number. A value of positive infinity is precision floating-point number. A value of positive infinity
represented as an IEEE single-precision floating-point number with is represented as an IEEE single-precision floating-point
an exponent of all ones (255) and a sign and mantissa of all number with an exponent of all ones (255) and a sign and
zeros. The values PDR and CDR are in units of bytes per second. mantissa of all zeros. The values PDR and CDR are in units of
The values PBS, CBS and EBS are in units of bytes. bytes per second. The values PBS, CBS and EBS are in units of
bytes.
The value of PDR MUST be greater than or equal to the value of CDR The value of PDR MUST be greater than or equal to the value of
in a correctly encoded Traffic Parameters TLV. CDR in a correctly encoded Traffic Parameters TLV.
4.3.1 Semantics 4.3.1 Semantics
4.3.1.1 Frequency 4.3.1.1 Frequency
CR-LDP Specification - 14 - Exp. August 1999
The Frequency specifies at what granularity the CDR allocated to the The Frequency specifies at what granularity the CDR allocated to the
CRLSP is made available. The value VeryFrequently means that the CRLSP is made available. The value VeryFrequently means that the
available rate should average at least the CDR when measured over any available rate should average at least the CDR when measured over
time interval equal to or longer than the shortest packet time at the any time interval equal to or longer than the shortest packet time
CDR. The value Frequently means that the available rate should at the CDR. The value Frequently means that the available rate
average at least the CDR when measured over any time interval equal should average at least the CDR when measured over any time interval
to or longer than a small number of shortest packet times at the CDR. equal to or longer than a small number of shortest packet times at
the CDR.
The value Unspecified means that the CDR MAY be provided at any The value Unspecified means that the CDR MAY be provided at any
granularity. granularity.
4.3.1.2 Peak Rate 4.3.1.2 Peak Rate
The Peak Rate defines the maximum rate at which traffic SHOULD be The Peak Rate defines the maximum rate at which traffic SHOULD be
sent to the CRLSP. The Peak Rate is useful for the purpose of sent to the CRLSP. The Peak Rate is useful for the purpose of
resource allocation. If resource allocation within the MPLS domain resource allocation. If resource allocation within the MPLS domain
depends on the Peak Rate value then it should be enforced at the depends on the Peak Rate value then it should be enforced at the
ingress to the MPLS domain. ingress to the MPLS domain.
The Peak Rate is defined in terms of the two Traffic Parameters PDR The Peak Rate is defined in terms of the two Traffic Parameters PDR
and PBS, see section 4.3.1.5 below. and PBS, see section 4.3.1.5 below.
4.3.1.3 Committed Rate 4.3.1.3 Committed Rate
The Committed Rate defines the rate that the MPLS domain commits to The Committed Rate defines the rate that the MPLS domain commits to
be available to the CRLSP. be available to the CRLSP.
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 13 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
The Committed Rate is defined in terms of the two Traffic Parameters The Committed Rate is defined in terms of the two Traffic Parameters
CDR and CBS, see section 4.3.1.6 below. CDR and CBS, see section 4.3.1.6 below.
4.3.1.4 Excess Burst Size 4.3.1.4 Excess Burst Size
The Excess Burst Size may be used at the edge of an MPLS domain for The Excess Burst Size may be used at the edge of an MPLS domain for
the purpose of traffic conditioning. The EBS MAY be used to measure the purpose of traffic conditioning. The EBS MAY be used to measure
the extent by which the traffic sent on a CRLSP exceeds the committed the extent by which the traffic sent on a CRLSP exceeds the
rate. committed rate.
The possible traffic conditioning actions, such as passing, marking The possible traffic conditioning actions, such as passing, marking
or dropping, are specific to the MPLS domain. or dropping, are specific to the MPLS domain.
The Excess Burst Size is defined together with the Committed Rate, The Excess Burst Size is defined together with the Committed Rate,
see section 4.3.1.6 below. see section 4.3.1.6 below.
4.3.1.5 Peak Rate Token Bucket 4.3.1.5 Peak Rate Token Bucket
The Peak Rate of a CRLSP is specified in terms of a token bucket P The Peak Rate of a CRLSP is specified in terms of a token bucket P
with token rate PDR and maximum token bucket size PBS. with token rate PDR and maximum token bucket size PBS.
The token bucket P is initially (at time 0) full, i.e., the token The token bucket P is initially (at time 0) full, i.e., the token
count Tp(0) = PBS. Thereafter, the token count Tp, if less than PBS, count Tp(0) = PBS. Thereafter, the token count Tp, if less than
is incremented by one PDR times per second. When a packet of size B PBS, is incremented by one PDR times per second. When a packet of
bytes arrives at time t, the following happens: size B bytes arrives at time t, the following happens:
CR-LDP Specification - 15 - Exp. August 1999
o If Tp(t)-B >= 0, the packet is not in excess of the peak - If Tp(t)-B >= 0, the packet is not in excess of the peak rate
rate and Tp is decremented by B down to the minimum value and Tp is decremented by B down to the minimum value of 0, else
of 0, else
o the packet is in excess of the peak rate and Tp is - the packet is in excess of the peak rate and Tp is not
not decremented. decremented.
Note that according to the above definition, a positive infinite Note that according to the above definition, a positive infinite
value of either PDR or PBS implies that arriving packets are never in value of either PDR or PBS implies that arriving packets are ever in
excess of the peak rate. excess of the peak rate.
The actual implementation of a LSR doesn't need to be modeled The actual implementation of a LSR doesn't need to be modeled
according to the above formal token bucket specification. according to the above formal token bucket specification.
4.3.1.6 Committed Data Rate Token Bucket 4.3.1.6 Committed Data Rate Token Bucket
The committed rate of a CRLSP is specified in terms of a token bucket The committed rate of a CRLSP is specified in terms of a token
C with rate CDR. The extent by which the offered rate exceeds the bucket C with rate CDR. The extent by which the offered rate
committed rate MAY be measured in terms of another token bucket E, exceeds the committed rate MAY be measured in terms of another token
which also operates at rate CDR. The maximum size of the token bucket E, which also operates at rate CDR. The maximum size of the
bucket C is CBS and the maximum size of the token bucket E is EBS. token bucket C is CBS and the maximum size of the token bucket E is
EBS.
The token buckets C and E are initially (at time 0) full, i.e., the The token buckets C and E are initially (at time 0) full, i.e., the
token count Tc(0) = CBS and the token count Te(0) = EBS. Thereafter, token count Tc(0) = CBS and the token count Te(0) = EBS.
the token counts Tc and Te are updated CDR times per second as Thereafter, the token counts Tc and Te are updated CDR times per
follows: second as follows:
o If Tc is less than CBS, Tc is incremented by one, else
o if Te is less then EBS, Te is incremented by one, else Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 14 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
o neither Tc nor Te is incremented. - If Tc is less than CBS, Tc is incremented by one, else
- if Te is less then EBS, Te is incremented by one, else
- neither Tc nor Te is incremented.
When a packet of size B bytes arrives at time t, the following When a packet of size B bytes arrives at time t, the following
happens: happens:
o If Tc(t)-B >= 0, the packet is not in excess of the Committed - If Tc(t)-B >= 0, the packet is not in excess of the Committed
Rate and Tc is decremented Rate and Tc is decremented by B down to the minimum value of 0,
by B down to the minimum value of 0, else else
- if Te(t)-B >= 0, the packet is in excess of the Committed rate
o if Te(t)-B >= 0, the packet is in excess of the Committed Rate but is not in excess of the EBS and Te is decremented by B down
but is not in excess of the EBS and Te is to the minimum value of 0, else
decremented by B down to the minimum value of 0, else - the packet is in excess of both the Committed Rate and the EBS
o the packet is in excess of both the Committed Rate and the EBS
and neither Tc nor Tc is decremented. and neither Tc nor Tc is decremented.
Note that according to the above specification, a CDR value of Note that according to the above specification, a CDR value of
positive infinity implies that arriving packets are never in excess positive infinity implies that arriving packets are never in excess
of either the Committed Rate or EBS. A positive infinite value of of either the Committed Rate or EBS. A positive infinite value of
either CBS or EBS implies that the respective limit cannot be either CBS or EBS implies that the respective limit cannot be
CR-LDP Specification - 16 - Exp. August 1999
exceeded. exceeded.
The actual implementation of a LSR doesn't need to be modeled The actual implementation of a LSR doesn't need to be modeled
according to the above formal specification. according to the above formal specification.
4.3.1.7 Weight 4.3.1.7 Weight
The weight determines the CRLSP's relative share of the possible The weight determines the CRLSP's relative share of the possible
excess bandwidth above its committed rate. The definition of excess bandwidth above its committed rate. The definition of
"relative share" is MPLS domain specific. _relative share_ is MPLS domain specific.
4.3.2 Procedures 4.3.2 Procedures
4.3.2.1 Label Request Message 4.3.2.1 Label Request Message
If an LSR receives an incorrectly encoded Traffic Parameters TLV in If an LSR receives an incorrectly encoded Traffic Parameters TLV in
which the value of PDR is less than the value of CDR then it MUST which the value of PDR is less than the value of CDR then it MUST
send a Notification Message including the Status code Traffic send a Notification Message including the Status code Traffic
Parameters Unavailable to the upstream LSR from which it received the Parameters Unavailable to the upstream LSR from which it received
erroneous message. the erroneous message.
If a Traffic Parameter is indicated as Negotiable in the Label If a Traffic Parameter is indicated as Negotiable in the Label
Request Message by the corresponding Negotiable Flag then an LSR MAY Request Message by the corresponding Negotiable Flag then an LSR MAY
replace the Traffic Parameter value with a smaller value. replace the Traffic Parameter value with a smaller value.
If the Weight is indicated as Negotiable in the Label Request Message If the Weight is indicated as Negotiable in the Label Request
by the corresponding Negotiable Flag then an LSR may adjust replace Message by the corresponding Negotiable Flag then an LSR may adjust
the Weight value with a lower value (down to 1). replace the Weight value with a lower value (down to 0).
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 15 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
If, after possible Traffic Parameter negotiation, an LSR can support If, after possible Traffic Parameter negotiation, an LSR can support
the CRLSP Traffic Parameters then the LSR MUST reserve the the CRLSP Traffic Parameters then the LSR MUST reserve the
corresponding resources for the CRLSP. corresponding resources for the CRLSP.
If, after possible Traffic Parameter negotiation, an LSR cannot If, after possible Traffic Parameter negotiation, an LSR cannot
support the CRLSP Traffic Parameters then the LSR MUST send a support the CRLSP Traffic Parameters then the LSR MUST send a
notification message that contains the Resource Unavailable status notification message that contains the Resource Unavailable status
code. code.
4.3.2.2 Label Mapping Message 4.3.2.2 Label Mapping Message
If an LSR receives an incorrectly encoded Traffic Parameters TLV in If an LSR receives an incorrectly encoded Traffic Parameters TLV in
which the value of PDR is less than the value of CDR then it MUST which the value of PDR is less than the value of CDR then it MUST
send a Label Release message containing the Status code Traffic send a Label Release message containing the Status code Traffic
Parameters Unavailable to the LSR from which it received the Parameters Unavailable to the LSR from which it received the
erroneous message. erroneous message.
The egress LSR MUST include the (possibly negotiated) Traffic If the negotiation flag was set in the label request message, the
Parameters and Weight in the Label Mapping message. egress LSR MUST include the (possibly negotiated) Traffic Parameters
and Weight in the Label Mapping message.
The Traffic Parameters and the Weight in a Label Mapping message MUST
be forwarded unchanged.
CR-LDP Specification - 17 - Exp. August 1999 The Traffic Parameters and the Weight in a Label Mapping message
MUST be forwarded unchanged.
An LSR SHOULD adjust the resources that it reserved for a CRLSP when An LSR SHOULD adjust the resources that it reserved for a CRLSP when
it receives a Label Mapping Message if the Traffic Parameters differ it receives a Label Mapping Message if the Traffic Parameters differ
from those in the corresponding Label Request Message. from those in the corresponding Label Request Message.
4.3.2.3 Notification Message 4.3.2.3 Notification Message
If an LSR receives a Notification Message for a CRLSP, it SHOULD If an LSR receives a Notification Message for a CRLSP, it SHOULD
release any resources that it possibly had reserved for the CRLSP. release any resources that it possibly had reserved for the CRLSP.
In addition, on receiving a Notification Message from a Downstream In addition, on receiving a Notification Message from a Downstream
LSR that is associated with a Label Request from an upstream LSR, the LSR that is associated with a Label Request from an upstream LSR,
local LSR MUST propagate the Notification message using the the local LSR MUST propagate the Notification message using the
procedures in [LDP]. procedures in [1].
4.4 Preemption TLV 4.4 Preemption TLV
The defualt value of the setup and holding priorities should be in
the middle of the range (e.g., 4) so that this feature can be turned
on gradually in an operational network by increasing or decerasing
the priority starting at the middle of the range.
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| Preemption-TLV (0x0820) | Length | |0|0| Preemption-TLV (0x0820) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SetPrio | HoldPrio | Reserved | | SetPrio | HoldPrio | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
U bit Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 16 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
Unknown TLV bit. As defined in [LDP].
F bit
Forward unknown TLV bit. As defined in [LDP].
Type Type
A fourteen-bit field carrying the value of the Preemption-TLV A fourteen-bit field carrying the value of the Preemption-TLV
type which is 0x810. type which is 0x810.
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes.
Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
SetPrio SetPrio
A SetupPriority of value zero (0) is the priority assigned to the A SetupPriority of value zero (0) is the priority assigned to
most important path. It is referred to as the highest priority. the most important path. It is referred to as the highest
Seven (7) is the priority for the least important path. The higher priority. Seven (7) is the priority for the least important
the setup priority, the more paths CR-LDP can bump to set up the path. The higher the setup priority, the more paths CR-LDP can
path. bump to set up the path. The default value should be 4.
HoldPrio HoldPrio
A HoldingPriority of value zero (0) is the priority assigned to A HoldingPriority of value zero (0) is the priority assigned to
the most important path. It is referred to as the highest the most important path. It is referred to as the highest
priority. Seven (7) is the priority for the least important path. priority. Seven (7) is the priority for the least important
path. The default value should be 4.
CR-LDP Specification - 18 - Exp. August 1999 The higher the holding priority, the less likely it is for CR-
LDP to reallocate its bandwidth to a new path.
The higher the holding priority, the less likely it is for CR-LDP
to reallocate its bandwidth to a new path.
4.5 LSPID TLV 4.5 LSPID TLV
LSPID is a unique identifier of a CRLSP within an MPLS network. LSPID is a unique identifier of a CRLSP within an MPLS network.
The LSPID is composed of the ingress LSR Router ID and a Locally The LSPID is composed of the ingress LSR Router ID and a Locally
unique CRLSP ID to that LSR. unique CRLSP ID to that LSR.
The LSPID is useful in network management, in CR-LSP repair, and in The LSPID is useful in network management, in CR-LSP repair, and in
using an already established CR-LSP as a hop in an ER-TLV. using an already established CR-LSP as a hop in an ER-TLV. An action
indicator flag_ is carried in the LSPID TLV. This _action indicator
flag_ indicates explicitly the action that should be taken if the
LSP already exists on the LSR receiving the message.
The procedure for the code point _modify_ is defined in section 2.1.
of [10]. The procedures for other flags are FFS.
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| LSPID-TLV (0x0821) | Length | |0|0| LSPID-TLV (0x0821) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Local CRLSP ID | | Reserved |ActFlg | Local CRLSP ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Ingress LSR Router ID | | Ingress LSR Router ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
U bit Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 17 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
Unknown TLV bit. As defined in [LDP].
F bit
Forward unknown TLV bit. As defined in [LDP].
Type Type
A fourteen-bit field carrying the value of the LSPID-TLV A fourteen-bit field carrying the value of the LSPID-TLV type
type which is 0x821. which is 0x821.
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes.
ActFlg
Action Indicator Flag: A 4-bit field that indicates explicitly
the action that should be taken if the LSP already exists on
the LSR receiving the message. A set of indicator code points
is proposed as follows:
0001: modify
Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
Local CRLSP ID Local CRLSP ID
The Local LSP ID is an identifier of the CRLSP locally unique The Local LSP ID is an identifier of the CRLSP locally unique
within the Ingress LSR originating the CRLDP. within the Ingress LSR originating the CRLDP.
Ingress LSR Router ID Ingress LSR Router ID
A 4 byte field indicating the Ingress LSR ID. "An LSR may use any of its own IPv4 in this field"
4.6 Resource Class (Color) TLV 4.6 Resource Class (Color) TLV
The Resource Class as defined in [TER] is used to specify which links The Resource Class as defined in [4] is used to specify which links
are acceptable by this CRLSP. This information allows for the are acceptable by this CRLSP. This information allows for the
network's topology to be pruned.
CR-LDP Specification - 19 - Exp. August 1999
networks topology to be pruned.
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| ResCls-TLV (0x0822) | Length | |0|0| ResCls-TLV (0x0822) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RsCls | | RsCls |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
U bit
Unknown TLV bit. As defined in [LDP].
F bit
Forward unknown TLV bit. As defined in [LDP].
Type Type
A fourteen-bit field carrying the value of the ResCls-TLV A fourteen-bit field carrying the value of the ResCls-TLV type
type which is 0x822. which is 0x822.
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes.
RsCls RsCls
The Resource Class bit mask indicating which of the The Resource Class bit mask indicating which of the 32
32 "administrative groups" or "colors" of links _administrative groups_ or _colors_ of links the CRLSP can
the CRLSP can traverse. traverse.
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 18 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
4.7 ER-Hop semantics 4.7 ER-Hop semantics
4.7.1. ER-Hop 1: The IPv4 prefix 4.7.1. ER-Hop 1: The IPv4 prefix
The abstract node represented by this ER-Hop is the set of nodes The abstract node represented by this ER-Hop is the set of nodes,
which have an IP address which lies within this prefix. Note that a which have an IP address, which lies within this prefix. Note that
prefix length of 32 indicates a single IPv4 node. a prefix length of 32 indicates a single IPv4 node.
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| 0x801 | Length | |0|0| 0x801 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Reserved | PreLen | |L| Reserved | PreLen |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Address (4 bytes) | | IPv4 Address (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
U bit
Unknown TLV bit. As defined in [LDP].
F bit
Forward unknown TLV bit. As defined in [LDP].
CR-LDP Specification - 20 - Exp. August 1999
Type Type
IPv4 Address 0x801 IPv4 Address 0x801
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes.
L Bit L Bit
Set to indicate Loose hop. Set to indicate Loose hop.
Cleared to indicate a strict hop. Cleared to indicate a strict hop.
Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
PreLen PreLen
Prefix Length 1-32 Prefix Length 1-32
IP Address IP Address
A four byte field indicating the IP Address. A four-byte field indicating the IP Address.
4.7.2. ER-Hop 2: The IPv6 address 4.7.2. ER-Hop 2: The IPv6 address
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| 0x802 | Length | |0|0| 0x802 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Reserved | PreLen | |L| Reserved | PreLen |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPV6 address | | IPV6 address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPV6 address (continued) | | IPV6 address (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPV6 address (continued) | | IPV6 address (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPV6 address (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
U bit Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 19 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
Unknown TLV bit. As defined in [LDP].
F bit | IPV6 address (continued) |
Forward unknown TLV bit. As defined in [LDP]. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
0x802 IPv6 address 0x802 IPv6 address
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes.
L Bit L Bit
Set to indicate Loose hop. Set to indicate Loose hop.
CR-LDP Specification - 21 - Exp. August 1999
Cleared to indicate a strict hop. Cleared to indicate a strict hop.
Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
PreLen PreLen
Prefix Length 1-128 Prefix Length 1-128
IPv6 address IPv6 address
A 128-bit unicast host address. A 128-bit unicast host address.
4.7.3. ER-Hop 32: The autonomous system number 4.7.3. ER-Hop 3: The autonomous system number
The abstract node represented by this ER-Hop is the set of nodes The abstract node represented by this ER-Hop is the set of nodes
belonging to the autonomous system. belonging to the autonomous system.
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| 0x803 | Length | |0|0| 0x803 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Reserved | AS Number | |L| Reserved | AS Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
U bit
Unknown TLV bit. As defined in [LDP].
F bit
Forward unknown TLV bit. As defined in [LDP].
Type Type
AS Number 0x803 AS Number 0x803
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes.
L Bit L Bit
Set to indicate Loose hop. Set to indicate Loose hop.
Cleared to indicate a strict hop. Cleared to indicate a strict hop.
Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
AS Number AS Number
Autonomous System number Autonomous System number
4.7.4. ER-Hop 4: LSPID 4.7.4. ER-Hop 4: LSPID
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 20 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
The LSPID is used to identify the tunnel ingress point as the next The LSPID is used to identify the tunnel ingress point as the next
hop in the ER. This ER-Hop allows for stacking new CR-LSPs within an hop in the ER. This ER-Hop allows for stacking new CR-LSPs within an
already established CR-LSP. It also allows for splicing the CR-LSP already established CR-LSP. It also allows for splicing the CR-LSP
being established with an existing CR-LSP.
CR-LDP Specification - 22 - Exp. August 1999 If an LSPID Hop is the last ER-Hop in an ER-TLV, than the LSR may
splice the CR-LSP of the incoming Label Request to the CR-LSP that
currently exists with this LSPID. This is useful, for example, at
the point at which a Label Request used for local repair arrives at
the next ER-Hop after the loosely specified CR-LSP segment. Use of
the LSPID Hop in this scenario eliminates the need for ER-Hops to
keep the entire remaining ER-TLV at each LSR that is at either
(upstream or downstream) end of a loosely specified CR-LSP segment
as part of its state information. This is due to the fact that the
upstream LSR needs only to keep the next ER-Hop and the LSPID and
the downstream LSR needs only to keep the LSPID in order for each
end to be able to recognize that the same LSP is being identified.
being established with an existing CR-LSP. If the LSPID Hop is not the last hop in an ER-TLV, the LSR must
forward the remaining ER-TLV in a Label Request message, using the
CR-LSP specified by the LSPID, to the LSR that is the CR-LSP's
egress. That LSR will continue processing of the CR-LSP Label
Request Message. The result is a tunneled, or stacked, CR-LSP.
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| 0x804 | Length | |0|0| 0x804 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Reserved | Local LSPID | |L| Reserved | Local LSPID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Ingress LSR Router ID | | Ingress LSR Router ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
U bit
Unknown TLV bit. As defined in [LDP].
F bit
Forward unknown TLV bit. As defined in [LDP].
Type Type
LSPID 0x804 LSPID 0x804
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes.
L Bit L Bit
Set to indicate Loose hop. Set to indicate Loose hop.
Cleared to indicate a strict hop. Cleared to indicate a strict hop.
Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
Local LSPID Local LSPID
A 2 byte field indicating the LSPID which is unique A 2 byte field indicating the LSPID which is unique with
with reference to the its Ingress LSR. reference to its Ingress LSR.
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 21 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
Ingress LSR Router ID Ingress LSR Router ID
A 4 byte field indicating the Ingress LSR ID. "An LSR may use any of its own IPv4 addresses in this field"
4.8. Processing of the Explicit Route TLV 4.8. Processing of the Explicit Route TLV
4.8.1. Selection of the next hop 4.8.1. Selection of the next hop
A Label Request Message containing a explicit route TLV must A Label Request Message containing a explicit route TLV must
determine the next hop for this path. Selection of this next hop may determine the next hop for this path. Selection of this next hop
involve a selection from a set of possible alternatives. The may involve a selection from a set of possible alternatives. The
mechanism for making a selection from this set is implementation mechanism for making a selection from this set is implementation
dependent and is outside of the scope of this specification. dependent and is outside of the scope of this specification.
Selection of particular paths is also outside of the scope of this Selection of particular paths is also outside of the scope of this
specification, but it is assumed that each node will make a best specification, but it is assumed that each node will make a best
effort attempt to determine a loop-free path. Note that such best effort attempt to determine a loop-free path. Note that such best
CR-LDP Specification - 23 - Exp. August 1999
efforts may be overridden by local policy. efforts may be overridden by local policy.
To determine the next hop for the path, a node performs the following To determine the next hop for the path, a node performs the
steps: following steps:
1) The node receiving the Label Request Message must first 1. The node receiving the Label Request Message must first
evaluate the first ER-Hop. If the L bit is not set in the first evaluate the first ER-Hop. If the L bit is not set in the
ER-Hop and if the node is not part of the abstract node described first ER-Hop and if the node is not part of the abstract node
by the first ER-Hop, it has received the message in error, and described by the first ER-Hop, it has received the message in
should return a "Bad initial ER-Hop" error. If the L bit is set error, and should return a _Bad initial ER-Hop_ error. If the
and the local node is not part of the abstract node described by L bit is set and the local node is not part of the abstract
the first ER-Hop, the node selects a next hop that is along the node described by the first ER-Hop, the node selects a next
path to the abstract node described by the first ER-Hop. If there hop that is along the path to the abstract node described by
is no first ER-Hop, the message is also in error and the system the first ER-Hop. If there is no first ER-Hop, the message is
should return a "Bad Explicit Routing TLV" error. also in error and the system should return a _Bad Explicit
Routing TLV_ error.
2) If there is no second ER-Hop, this indicates the end of the 2. If there is no second ER-Hop, this indicates the end of the
explicit route. The explicit route TLV should be removed from the explicit route. The explicit route TLV should be removed from
Label Request Message. This node may or may not be the end of the the Label Request Message. This node may or may not be the
LSP. Processing continues with section 4.8.2, where a new end of the LSP. Processing continues with section 4.8.2,
explicit route TLV may be added to the Label Request Message. where a new explicit route TLV may be added to the Label
Request Message.
3) If the node is also a part of the abstract node described by 3. If the node is also a part of the abstract node described by
the second ER-Hop, then the node deletes the first ER-Hop and the second ER-Hop, then the node deletes the first ER-Hop and
continues processing with step 2, above. Note that this makes the continues processing with step 2, above. Note that this makes
second ER-Hop into the first ER-Hop of the next iteration. the second ER-Hop into the first ER-Hop of the next iteration.
4) The node determines if it is topologically adjacent to the 4. The node determines if it is topologically adjacent to the
abstract node described by the second ER-Hop. If so, the node abstract node described by the second ER-Hop. If so, the node
selects a particular next hop which is a member of the abstract selects a particular next hop which is a member of the
node. The node then deletes the first ER-Hop and continues abstract node. The node then deletes the first ER-Hop and
processing with section 4.8.2. continues processing with section 4.8.2.
5) Next, the node selects a next hop within the abstract node of Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 22 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
the first ER-Hop that is along the path to the abstract node of
the second ER-Hop. If no such path exists then there are two
cases:
5a) If the second ER-Hop is a strict ER-Hop, then there is an 5. Next, the node selects a next hop within the abstract node of
error and the node should return a "Bad strict node" error. the first ER-Hop that is along the path to the abstract node
of the second ER-Hop. If no such path exists then there are
two cases:
5b) Otherwise, if the second ER-Hop is a loose ER-Hop, then the 5.a If the second ER-Hop is a strict ER-Hop, then there is
node selects any next hop that is along the path to the next an error and the node should return a _Bad strict node_
abstract node. If no path exists within the MPLS domain, then
there is an error, and the node should return a "Bad loose node"
error. error.
6) Finally, the node replaces the first ER-Hop with any ER-Hop 5.b Otherwise, if the second ER-Hop is a loose ER-Hop, then
that denotes an abstract node containing the next hop. This is the node selects any next hop that is along the path to the
necessary so that when the explicit route is received by the next next abstract node. If no path exists within the MPLS
hop, it will be accepted. domain, then there is an error, and the node should return a
_Bad loose node_ error.
CR-LDP Specification - 24 - Exp. August 1999 6. Finally, the node replaces the first ER-Hop with any ER-Hop
that denotes an abstract node containing the next hop. This
is necessary so that when the explicit route is received by
the next hop, it will be accepted.
7) Progress the Label Request Message to the next hop. 7. Progress the Label Request Message to the next hop.
4.8.2. Adding ER-Hops to the explicit route TLV 4.8.2. Adding ER-Hops to the explicit route TLV
After selecting a next hop, the node may alter the explicit route in After selecting a next hop, the node may alter the explicit route in
the following ways. the following ways.
If, as part of executing the algorithm in section 4.8.1, the explicit If, as part of executing the algorithm in section 4.8.1, the
route TLV is removed, the node may add a new explicit route TLV. explicit route TLV is removed, the node may add a new explicit route
TLV.
Otherwise, if the node is a member of the abstract node for the first Otherwise, if the node is a member of the abstract node for the
ER-Hop, then a series of ER-Hops may be inserted before the first first ER-Hop, then a series of ER-Hops may be inserted before the
ER-Hop or may replace the first ER-Hop. Each ER-Hop in this series first ER-Hop or may replace the first ER-Hop. Each ER-Hop in this
must denote an abstract node that is a subset of the current abstract series must denote an abstract node that is a subset of the current
node. abstract node.
Alternately, if the first ER-Hop is a loose ER-Hop, an arbitrary Alternately, if the first ER-Hop is a loose ER-Hop, an arbitrary
series of ER-Hops may be inserted prior to the first ER-Hop. series of ER-Hops may be inserted prior to the first ER-Hop.
4.9 Route Pinning TLV 4.9 Route Pinning TLV
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| 0x823 | Length | |0|0| 0x823 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|P| Reserved | |P| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
U bit
Unknown TLV bit. As defined in [LDP].
F bit
Forward unknown TLV bit. As defined in [LDP].
Type Type
Pinning-TLV type 0x823 Pinning-TLV type 0x823
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 23 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes.
P Bit P Bit
The P bit is set to 1 to indicate that route pinning is requested. The P bit is set to 1 to indicate that route pinning is
requested.
The P bit is set to 0 to indicate that route pinning is not The P bit is set to 0 to indicate that route pinning is not
requested requested
Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
4.10 CRLSP FEC Element 4.10 CRLSP FEC Element
CR-LDP Specification - 25 - Exp. August 1999
A new FEC element is introduced in this specification to support CR- A new FEC element is introduced in this specification to support CR-
LSPs. The CRLDP FEC Element is an opaque FEC. LSPs. This new FEC element does not preclude the use of other FECs
elements (Type=0x01, 0x02, 0x03) defined in the LDP spec in CR-LDP
messages. The CRLDP FEC Element is an opaque FEC to be used only in
Messages of CR-LSPs.
FEC Element Type Value FEC Element Type Value
type name Type name
CRLSP 0x04 No value; i.e., 0 value octets; CRLSP 0x04 No value; i.e., 0 value octets;
see below.
CRLSP FEC Element
To be used only in Messages of CR-LSPs.
The CR-LSP FEC TLV encoding is as follows: The CR-LSP FEC TLV encoding is as follows:
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| FEC(0x0100) | Length | |0|0| FEC(0x0100) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CR-LSP (4) | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CR-LSP (4) |
U bit +-+-+-+-+-+-+-+-+
Unknown TLV bit. As defined in [LDP].
F bit
Forward unknown TLV bit. As defined in [LDP].
Type Type
FEC TLV type 0x0100 FEC TLV type 0x0100
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes.
CR-LSP FEC Element Type CR-LSP FEC Element Type
0x04 0x04
Reserved
Zero on transmission. Ignored on receipt.
4.11 Error subcodes 4.11 Error subcodes
In the processing described above, certain errors need to be reported In the processing described above, certain errors need to be
as part of the Notification Message. This section defines the status reported as part of the Notification Message. This section defines
codes for the errors described in this specification. the status codes for the errors described in this specification.
CR-LDP Specification - 26 - Exp. August 1999 Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 24 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
Status Code Type Status Code Type
-------------------------------------- ---------- -------------------------------------- ----------
Bad Explicit Routing TLV Error 0x04000001 Bad Explicit Routing TLV Error 0x44000001
Bad Strict Node Error 0x04000002 Bad Strict Node Error 0x44000002
Bad Loose Node Error 0x04000003 Bad Loose Node Error 0x44000003
Bad Initial ER-Hop Error 0x04000004 Bad Initial ER-Hop Error 0x44000004
Resource Unavailable 0x04000005 Resource Unavailable 0x44000005
Traffic Parameters Unavailable 0x04000006 Traffic Parameters Unavailable 0x44000006
Setup abort 0x04000007 Setup abort (Label Request Aborted in [1]) 0x04000015
Modify request not supported 0x44000008
5. Security 5. Security
Pre-emption has to be controlled by the MPLS domain. Pre-emption has to be controlled by the MPLS domain.
Resource reservation requires the LSRs to have an LSP admission Resource reservation requires the LSRs to have an LSP admission
control function. control function.
Normal routing can be bypassed by Traffic Engineered LSPs. Traffic Engineered LSPs can bypass normal routing.
6. Acknowledgments 6. Acknowledgments
The messages used to signal the CRLSP setup are based on the work The messages used to signal the CRLSP setup are based on the work
done by the [LDP] team. The Explicit Route object and procedures used done by the [1] team. The Explicit Route object and procedures used
in this specification are based on [ER]. in this specification are based on [8].
The authors would also like to acknowledge the careful review and The authors would also like to acknowledge the careful review and
comments of Ken Hayward, Greg Wright, Geetha Brown, Brian Williams, comments of Ken Hayward, Greg Wright, Geetha Brown, Brian Williams,
Paul Beaubien, Matthew Yuen, Liam Casey, and Ankur Anand. Paul Beaubien, Matthew Yuen, Liam Casey, and Ankur Anand.
7. References 7. Intellectual Property Consideration
[LDP] Andersson et al, "Label Distribution Protocol Specification" Nortel Networks may seek patent or other intellectual property
work in progress (draft-ietf-mpls-ldp-03), Feb. 1999. protection for some or all of the technologies disclosed in this
document. If any standards arising from this document are or become
protected by one or more patents assigned to Nortel Networks, Nortel
Networks is prepared to make a license available to any qualified
applicant upon reasonable and non-discriminatory terms and
conditions. Any such licenses will be subject to negotiations
outside of the IETF.
[ARCH] Rosen et al, "Multiprotocol Label Switching Architecture", 8. References
work in progress (draft-ietf-mpls-arch-04), Feb. 1999.
[FRAME] Callon et al, "Framework for Multiprotocol Label Switching", 1 Andersson et al, "Label Distribution Protocol Specification"
work in progress (draft-ietf-mpls-framework-02), November work in progress (draft-ietf-mpls-ldp-05), June 1999.
1997.
[TER] Awduche et al, "Requirements for Traffic Engineering Over 2 Callon et al, "Framework for Multiprotocol Label Switching",
MPLS", work in progress (draft-ietf-mpls-traffic-eng-00), work in progress (draft-ietf-mpls-framework-04), July 1999.
August 1998.
[ER] Guerin et al, "Setting up Reservations on Explicit Paths 3 Rosen et al, "Multiprotocol Label Switching Architecture",
using RSVP", work in progress (draft-guerin-expl-path-rsvp- work in progress (draft-ietf-mpls-arch-04), April 1999.
01)
November 1997.
CR-LDP Specification - 27 - Exp. August 1999 Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 25 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
[VPN1] Heinanen et al, "MPLS Mappings of Generic VPN Mechanisms", 4 Awduche et al, "Requirements for Traffic Engineering Over
MPLS", work in progress (draft-ietf-mpls-traffic-eng-01),
June 1999.
5 Heinanen et al, "MPLS Mappings of Generic VPN Mechanisms",
work in progress (draft-heinanen-generic-vpn-mpls-00), work in progress (draft-heinanen-generic-vpn-mpls-00),
August 1998. August 1998.
[VPN2] Jamieson et al, "MPLS VPN Architecture" work in progress 6 Jamieson et al, "MPLS VPN Architecture" work in progress
(draft-jamieson-mpls-vpn-00), August 1998. (draft-jamieson-mpls-vpn-00), August 1998.
[VPN3] T. Li, "CPE based VPNs using MPLS", work in progress (draft- 7 T. Li, "CPE based VPNs using MPLS", work in progress (draft-
li-mpls-vpn-00.txt), October 1998. li-mpls-vpn-00.txt), October 1998.
[LDP-STATE] L. Wu, et. al., "LDP State Machine" work in progress 8 Guerin et al, "Setting up Reservations on Explicit Paths using
RSVP", work in progress (draft-guerin-expl-path-rsvp-01) November
1997.
9 L. Wu, et. al., "LDP State Machine" work in progress
(draft-ietf-mpls-ldp-state-00), Feb 1999. (draft-ietf-mpls-ldp-state-00), Feb 1999.
CR-LDP Specification - 28 - Exp. August 1999 10 J. Ash, et. al., _LSP Modification Using CR-LDP_ work in progress
(draft-ash-crlsp-modify-00.txt), July 1999.
8. Author Information 9. Author's Addresses
Osama S. Aboul-Magd Loa Andersson Osama S. Aboul-Magd Loa Andersson
Nortel Networks Director Bay Architecture Lab,EMEA Nortel Networks Nortel Networks
P O Box 3511 Station C Kungsgatan 34, PO Box 1788 P O Box 3511 Station C Kungsgatan 34, PO Box 1788
Ottawa, ON K1Y 4H7 111 97 Stockholm, Sweden Ottawa, ON K1Y 4H7 111 97 Stockholm, Sweden
Canada phone: +46 8 441 78 34 Canada Phone: +46 8 441 78 34
phone: +1 613 763-5827 mobile +46 70 522 78 34 Phone: +1 613 763-5827 Mobile +46 70 522 78 34
osama@NortelNetworks.com loa_andersson@baynetworks.com Osama@nortelnetworks.com Loa_andersson@beynetworks.com
Peter Ashwood-Smith Ross Callon Peter Ashwood-Smith Ross Callon
Nortel Networks IronBridge Networks Nortel Networks IronBridge Networks
P O Box 3511 Station C 55 Hayden Avenue, P O Box 3511 Station C 55 Hayden Avenue,
Ottawa, ON K1Y 4H7 Lexington, MA 02173 Ottawa, ON K1Y 4H7 Lexington, MA 02173
Canada Phone: +1-781-402-8017 Canada Phone: +1-781-402-8017
phone: +1 613 763-4534 rcallon@ironbridgenetworks.com Phone: +1 613 763-4534 Rcallon@ironbridgenetworks.com
petera@NortelNetworks.com Petera@nortelnetworks.com
Ram Dantu Paul Doolan Ram Dantu Paul Doolan
Alcatel USA Inc. Ennovate Networks Alcatel USA Inc. Ennovate Networks
IP Competence Center 330 Codman Hill Rd IP Competence Center 330 Codman Hill Rd
1201 E. Campbell Road.,446-315 Marlborough MA 01719 1201 E. Campbell Road.,446-315 Marlborough MA 01719
Richadson, TX USA., 75081-2206 Phone: 978-263-2002 Richadson, TX USA., 75081-2206 Phone: 978-263-2002
Phone: 972 996 2938 pdoolan@ennovatenetworks.com Phone: 972 996 2938 Pdoolan@ennovatenetworks.com
Fax: 972 996 5902 Fax: 972 996 5902
ram.dantu@aud.alcatel.com Ram.dantu@aud.alcatel.com
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 26 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
Nancy Feldman Andre Fredette Nancy Feldman Andre Fredette
IBM Corp. Nortel Networks IBM Corp. Nortel Networks
17 Skyline Drive 3 Federal Street 17 Skyline Drive 3 Federal Street
Hawthorne NY 10532 Billerica, MA 01821 Hawthorne NY 10532 Billerica, MA 01821
Phone: 914-784-3254 fredette@baynetworks.com Phone: 914-784-3254 978-288-8524
nkf@us.ibm.com Nkf@us.ibm.com Fredette@baynetworks.com
Eric Gray Joel M. Halpern Eric Gray Joel M. Halpern
Lucent Technologies, Inc Newbridge Networks Inc. Lucent Technologies, Inc Institutional Venture Partners
1600 Osgood St. 593 Herndon Parkway 1600 Osgood St. 650-926-5633
North Andover, MA 01847 Herndon, VA 20170 North Andover, MA 01847 joel@mcquillan.com
Phone: 603-659-3386 phone: 1-703-736-5954 Phone: 603-659-3386
ewgray@lucent.com jhalpern@newbridge.com Ewgray@lucent.com
Juha Heinanen Fiffi Hellstrand Juha Heinanen Fiffi Hellstrand
Telia Finland, Inc. Ericsson Telecom AB Telia Finland, Inc. Ericsson Telecom AB
Myyrmaentie 2 S-126 25 STOCKHOLM Myyrmaentie 2 S-126 25 STOCKHOLM
01600 VANTAA Sweden 01600 VANTAA Sweden
Finland Tel: +46 8 719 4933 Finland Tel: +46 8 719 4933
Tel: +358 41 500 4808 etxfiff@etxb.ericsson.se Tel: +358 41 500 4808 etxfiff@etxb.ericsson.se
jh@telia.fi Jh@telia.fi
CR-LDP Specification - 29 - Exp. August 1999
Bilel Jamoussi Timothy E. Kilty Bilel Jamoussi Timothy E. Kilty
Nortel Networks Northchurch Communications Nortel Networks Corp. Northchurch Communications
P O Box 3511 Station C 5 Corporate Drive, 3 Federal Street 5 Corporate Drive,
Ottawa, ON K1Y 4H7 Andover, MA 018110 Billerica, MA 01821 Andover, MA 018110
Canada phone: 978 691-4656 USA phone: 978 691-4656
phone: +1 613 765-4814 tkilty@northc.com Phone: +1 978 288-4506 tkilty@northc.com
jamoussi@NortelNetworks.com Jamoussi@nortelnetworks.com
Andrew G. Malis Muckai K Girish Andrew G. Malis Muckai K Girish
Ascend Communications, Inc. SBC Technology Resources, Inc. Ascend Communications, Inc. SBC Technology Resources,
1 Robbins Road 4698 Willow Road 1 Robbins Road 4698 Willow Road
Westford, MA 01886 Pleasanton, CA 94588 Westford, MA 01886 Pleasanton, CA 94588
phone: 978 952-7414 Phone: (925) 598-1263 Phone: 978 952-7414 Phone: (925) 598-1263
fax: 978 392-2074 Fax: (925) 598-1321 fax: 978 392-2074 Fax: (925) 598-1321
malis@ascend.com mgirish@tri.sbc.com Malis@ascend.com mgirish@tri.sbc.com
Kenneth Sundell Pasi Vaananen Kenneth Sundell Pasi Vaananen
Ericsson Nokia Telecommunications Nortel Networks Nokia Telecommunications
SE-126 25 Stockholm 3 Burlington Woods Drive, Suite 250 Architecture Lab, EMEA 3 Burlington Woods Drive,
Sweden Burlington, MA 01803 Kungsgatan 34, PO Box 1788 Burlington, MA 01803
kenneth.sundell@etx.ericsson.se Phone: +1-781-238-4981 111 97 Stockholm, Sweden Phone: +1-781-238-4981
pasi.vaananen@ntc.nokia.com phone: +46 8 441-7838, Pasi.vaananen@ntc.nokia.com
mobile +46 70 665-7838
ksundell@nortelnetworks.com
Tom Worster Liwen Wu Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 27 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
General DataComm, Inc. Alcatel U.S.A
5 Mount Royal Ave. 44983 Knoll Square
Marlboro MA 01752 Ashburn, Va. 20147
tom.worster@gdc.com USA
Phone: (703) 724-2619
FAX: (703) 724-2005
liwen.wu@adn.alcatel.com
CR-LDP Specification - 30 - Exp. August 1999 Tom worster Liwen Wu
Nokia Alcatel U.S.A
3 Burlington Woods Dr. 44983 Knoll Square
Suite 250 Ashburn, Va. 20147
Burlington MA 01803 USA Phone: (703) 724-2619
+1 617 247 2624 FAX: (703) 724-2005
tom.worster@nokia.com Liwen.wu@and.alcatel.com
Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 28 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
Appendix A: CRLSP Establishment Examples Appendix A: CRLSP Establishment Examples
A.1 Strict Explicit Route Example A.1 Strict Explicit Route Example
This appendix provides an example for the setup of a strictly routed This appendix provides an example for the setup of a strictly routed
CRLSP. In this example, each abstract node is represented by a CRLSP. In this example, a specific node represents each abstract
specific node. node.
The sample network used here is a four node network with two edge The sample network used here is a four node network with two
LSRs and two core LSRs as follows: edge LSRs and two core LSRs as follows:
a b c a b c
LSR1------LSR2------LSR3------LSR4 LSR1------LSR2------LSR3------LSR4
LSR1 generates a Label Request Message as described in Section 3.1 of LSR1 generates a Label Request Message as described in Section 3.1
this draft and sends it to LSR2. This message includes the CR-TLV. of this draft and sends it to LSR2. This message includes the CR-
TLV.
The ER-TLV is composed by a vector of three ER-Hop TLVs <a, b, c>.
The ER-Hop TLVs used in this example are of type 0x0801 (IPv4 prefix)
with a prefix length of 32. Hence, each ER-Hop TLV identifies a
specific node as opposed to a group of nodes.
A vector of three ER-Hop TLVs <a, b, c> composes the ER-TLV.
The ER-Hop TLVs used in this example are of type 0x0801 (IPv4
prefix) with a prefix length of 32. Hence, each ER-Hop TLV
identifies a specific node as opposed to a group of nodes.
At LSR2, the following processing of the ER-TLV per Section 4.8.1 of At LSR2, the following processing of the ER-TLV per Section 4.8.1 of
this draft takes place: this draft takes place:
1) The first hop <a> is part of the abstract node LSR2. Therefore, 1) The first hop <a> is part of the abstract node LSR2.
the first step passes the test. Go to step 2. Therefore, the first step passes the test. Go to step 2.
2) There is a second ER-Hop, <b>. Go to step 3. 2) There is a second ER-Hop, <b>. Go to step 3.
3) LSR2 is not part of the abstract node described by the second 3) LSR2 is not part of the abstract node described by the
ER-Hop <b>. Go to Step 4. second ER-Hop <b>. Go to Step 4.
4) LSR2 determines that it is topologically adjacent to the 4) LSR2 determines that it is topologically adjacent to the
abstract node described by the second ER-Hop <b>. LSR2 selects a abstract node described by the second ER-Hop <b>. LSR2 selects
next hop (LSR3) which is the abstract node. LSR2 deletes the first a next hop (LSR3) which is the abstract node. LSR2 deletes the
ER-Hop <a> from the ER-TLV which now becomes <b , c>. Go to first ER-Hop <a> from the ER-TLV which now becomes <b , c>. Go
Section 4.8.2. to Section 4.8.2.
At LSR2, the following processing of Section 4.8.2 takes place: At LSR2, the following processing of Section 4.8.2 takes place:
Executing algorithm 4.8.1 did not result in the removal of the ER-
Executing algorithm 4.8.1 did not result in the removal of the TLV.
ER-TLV.
Also, LSR2 is not a member of the abstract node described by the Also, LSR2 is not a member of the abstract node described by the
first ER-Hop <b>. first ER-Hop <b>.
Finally, the first ER-Hop <b> is a strict hop. Finally, the first ER-Hop <b> is a strict hop.
Therefore, processing section 4.8.2 does not result in the Therefore, processing section 4.8.2 does not result in the insertion
insertion of new ER-Hops. The selection of the next hop has been of new ER-Hops. The selection of the next hop has been already done
is step 4 of Section 4.8.1 and the processing of the ER-TLV is
CR-LDP Specification - 31 - Exp. August 1999 Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 29 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
already done is step 4 of Section 4.8.1 and the processing of the completed at LSR2. In this case, the Label Request Message including
ER-TLV is completed at LSR2. In this case, the Label Request the ER-TLV <b, c> is progressed by LSR2 to LSR3.
Message including the ER-TLV <b, c> is progressed by LSR2 to LSR3.
At LSR3, a similar processing to the ER-TLV takes place except that At LSR3, a similar processing to the ER-TLV takes place except that
the incoming ER-TLV = <b, c> and the outgoing ER-TLV is <c>. the incoming ER-TLV = <b, c> and the outgoing ER-TLV is <c>.
At LSR4, the following processing of section 4.8.1 takes place: At LSR4, the following processing of section 4.8.1 takes place:
1) The first hop <c> is part of the abstract node LSR4. Therefore, 1) The first hop <c> is part of the abstract node LSR4.
the first step passes the test. Go to step 2. Therefore, the first step passes the test. Go to step 2.
2) There is no second ER-Hop, this indicates the end of the CRLSP. 2) There is no second ER-Hop, this indicates the end of the
The ER-TLV is removed from the Label Request Message. Processing CRLSP. The ER-TLV is removed from the Label Request Message.
continues with Section 4.8.2. Processing continues with Section 4.8.2.
At LSR4, the following processing of Section 4.8.2 takes place: At LSR4, the following processing of Section 4.8.2 takes place:
Executing algorithm 4.8.1 resulted in the removal of the ER-TLV. Executing algorithm 4.8.1 resulted in the removal of the ER-TLV.
LSR4 does not add a new ER-TLV. LSR4 does not add a new ER-TLV.
Therefore, processing section 4.8.2 does not result in the Therefore, processing section 4.8.2 does not result in the insertion
insertion of new ER-Hops. This indicates the end of the CRLSP and of new ER-Hops. This indicates the end of the CRLSP and the
the processing of the ER-TLV is completed at LSR4. processing of the ER-TLV is completed at LSR4.
At LSR4, processing of Section 3.2 is invoked. The first condition is At LSR4, processing of Section 3.2 is invoked. The first condition
satisfied (LSR4 is the egress end of the CRLSP and upstream mapping is satisfied (LSR4 is the egress end of the CRLSP and upstream
has been requested). Therefore, a Label Mapping Message is generated mapping has been requested). Therefore, a Label Mapping Message is
by LSR4 and sent to LSR3. generated by LSR4 and sent to LSR3.
At LSR3, the processing of Section 3.2 is invoked. The second At LSR3, the processing of Section 3.2 is invoked. The second
condition is satisfied (LSR3 received a mapping from its downstream condition is satisfied (LSR3 received a mapping from its downstream
next hop LSR4 for a CRLSP for which an upstream request is still next hop LSR4 for a CRLSP for which an upstream request is still
pending). Therefore, a Label Mapping Message is generated by LSR3 and pending). Therefore, a Label Mapping Message is generated by LSR3
sent to LSR2. and sent to LSR2.
At LSR2, a similar processing to LSR 3 takes place and a Label At LSR2, a similar processing to LSR 3 takes place and a Label
Mapping Message is sent back to LSR1 which completes the end-to-end Mapping Message is sent back to LSR1 which completes the end-to-end
CRLSP setup. CRLSP setup.
A.2. Node Groups and Specific Nodes Example A.2. Node Groups and Specific Nodes Example
A request at an ingress LSR to setup a CRLSP might originate from a A request at ingress LSR to setup a CRLSP might originate from a
management system or an application, the details are implementation management system or an application, the details are implementation
specific. specific.
The ingress LSR uses information provided by the management system or The ingress LSR uses information provided by the management system
the application and possibly also information from the routing or the application and possibly also information from the routing
database to calculated the explicit route and to create the Label database to calculate the explicit route and to create the Label
Request Message. Request Message.
CR-LDP Specification - 32 - Exp. August 1999
The Label request message carries together with other necessary The Label request message carries together with other necessary
information a ER-TLV defining the explicitly routed path. In our information a ER-TLV defining the explicitly routed path. In our
example the list of hops in the ER-Hop TLV is supposed to contain an example the list of hops in the ER-Hop TLV is supposed to contain an
Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 30 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
abstract node representing a group of nodes, an abstract node abstract node representing a group of nodes, an abstract node
representing a specific node, another abstract node representing a representing a specific node, another abstract node representing a
group of nodes, and an abstract node representing a specific egress group of nodes, and an abstract node representing a specific egress
point. point.
In--{Group 1}--{Specific A}--{Group 2}--{Specific Out: B} In--{Group 1}--{Specific A}--{Group 2}--{Specific Out: B}
The ER-TLV contains four ER-Hop TLVs: The ER-TLV contains four ER-Hop TLVs:
1. An ER-Hop TLV that specifies a group of LSR valid for the first 1. An ER-Hop TLV that specifies a group of LSR valid for the
abstract node representing a group of nodes (Group 1). first abstract node representing a group of nodes (Group 1).
2. An ER-Hop TLV that indicates the specific node (Node A). 2. An ER-Hop TLV that indicates the specific node (Node A).
3. An ER-Hop TLV that specifies a group of LSRs valid for the 3. An ER-Hop TLV that specifies a group of LSRs valid for the
second abstract node representing a group of nodes (Group 2). second abstract node representing a group of nodes (Group
2).
4. An ER-Hop TLV that indicates the specific egress point for the 4. An ER-Hop TLV that indicates the specific egress point for
CRLSP (Node B). the CRLSP (Node B).
All the ER-Hop TLVs are strictly routed nodes. All the ER-Hop TLVs are strictly routed nodes.
The setup procedure for this CRLSP works as follows: The setup procedure for this CRLSP works as follows:
1. The ingress node sends the Label Request Message to a node that 1. The ingress node sends the Label Request Message to a node
is a member the group of nodes indicated in the first ER-Hop TLV, that is a member the group of nodes indicated in the first
following normal routing for the specific node (A). ER-Hop TLV, following normal routing for the specific node
(A).
2. The node that receives the message identifies itself as part of 2. The node that receives the message identifies itself as part
the group indicated in the first ER-Hop TLV, and that it is not of the group indicated in the first ER-Hop TLV, and that it
the specific node (A) in the second. Further it realizes that the is not the specific node (A) in the second. Further it
specific node (A) is not one of its next hops. realizes that the specific node (A) is not one of its next
hops.
3. It keeps the ER-Hop TLVs intact and sends a Label Request 3. It keeps the ER-Hop TLVs intact and sends a Label Request
Message to a node that is part of the group indicated in the first Message to a node that is part of the group indicated in the
ER-Hop TLV (Group 1), following normal routing for the specific first ER-Hop TLV (Group 1), following normal routing for the
node (A). specific node (A).
4. The node that receives the message identifies itself as part of 4. The node that receives the message identifies itself as part
the group indicated in the first ER-Hop TLV, and that it is not of the group indicated in the first ER-Hop TLV, and that it
the specific node (A) in the second ER-Hop TLV. Further it is not the specific node (A) in the second ER-Hop TLV.
realizes that the specific node (A) is one of its next hops. Further it realizes that the specific node (A) is one of its
next hops.
5. It removes the first ER-Hop TLVs and sends a Label Request 5. It removes the first ER-Hop TLVs and sends a Label Request
Message to the specific node (A). Message to the specific node (A).
6. The specific node (A) recognizes itself in the first ER-Hop 6. The specific node (A) recognizes itself in the first ER-Hop
TLV. Removes the specific ER-Hop TLV. TLV. Removes the specific ER-Hop TLV.
CR-LDP Specification - 33 - Exp. August 1999 Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 31 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
7. It sends a Label Request Message to a node that is a member of 7. It sends a Label Request Message to a node that is a member
the group (Group 2) indicated in the ER-Hop TLV. of the group (Group 2) indicated in the ER-Hop TLV.
8. The node that receives the message identifies itself as part of 8. The node that receives the message identifies itself as part
the group indicated in the first ER-Hop TLV, further it realizes of the group indicated in the first ER-Hop TLV, further it
that the specific egress node (B) is one of its next hops. realizes that the specific egress node (B) is one of its
next hops.
9. It sends a Label Request Message to the specific egress node 9. It sends a Label Request Message to the specific egress node
(B). (B).
10. The specific egress node (B) recognizes itself as the egress 10. The specific egress node (B) recognizes itself as the egress
for the CRLSP, it returns a Label Mapping Message, that will for the CRLSP, it returns a Label Mapping Message, that will
traverse the same path as the Label Request Message in the traverse the same path as the Label Request Message in the
opposite direction. opposite direction.
CR-LDP Specification - 34 - Exp. August 1999 Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 32 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
Appendix B. QoS Service Examples Appendix B. QoS Service Examples
B.1 Service Examples B.1 Service Examples
Construction of an end-to-end service is the result of the rules Construction of an end-to-end service is the result of the rules
enforced at the edge and the treatment that packets receive at the enforced at the edge and the treatment that packets receive at the
network nodes. The rules define the traffic conditioning actions that network nodes. The rules define the traffic conditioning actions
are implemented at the edge and they include policing with pass, that are implemented at the edge and they include policing with
mark, and drop capabilities. The edge rules are expected to be pass, mark, and drop capabilities. The edge rules are expected to
defined by the mutual agreements between the service providers and be defined by the mutual agreements between the service providers
their customers and they will constitute an essential part of the and their customers and they will constitute an essential part of
SLA. Therefore edge rules are not included in the signaling protocol. the SLA. Therefore edge rules are not included in the signaling
protocol.
Packets treatment at a network node is usually referred to as the Packet treatment at a network node is usually referred to as the
local behavior. Local behavior could be specified in many ways. One local behavior. Local behavior could be specified in many ways. One
example for local behavior specification is the service frequency example for local behavior specification is the service frequency
introduced in section 4.3.2.1., together with the resource introduced in section 4.3.2.1, together with the resource
reservation rules implemented at the nodes. reservation rules implemented at the nodes.
Edge rules and local behaviors can be viewed as the main building Edge rules and local behaviors can be viewed as the main building
blocks for the end-to-end service construction. The following table blocks for the end-to-end service construction. The following table
illustrates the applicability of the building block approach for illustrates the applicability of the building block approach for
constructing different services including those defined for ATM. constructing different services including those defined for ATM.
Service PDR PBS CDR CBS EBS Service Conditioning Service PDR PBS CDR CBS EBS Service Conditioning
Examples Frequency Action Examples Frequency Action
DS S S =PDR =PBS 0 Frequent drop>PDR DS S S =PDR =PBS 0 Frequent drop>PDR
TS S S S S 0 Unspecified drop>PDR,PBS TS S S S S 0 Unspecified drop>PDR,PBS
mark>CDR,CBS mark>CDR,CBS
BE inf inf inf inf 0 Unspecified - BE inf inf inf inf 0 Unspecified -
FRS S S CIR ~B_C ~B_E Unspecified drop>PDR,PBS FRS S S CIR ~B_C ~B_E Unspecified drop>PDR,PBS
mark>CDR,CBS,EBS mark>CDR,CBS,EBS
skipping to change at page 35, line 5 skipping to change at line 1680
ATM-VBR.3(rt) PCR CDVT SCR MBS 0 Frequent drop>PCR ATM-VBR.3(rt) PCR CDVT SCR MBS 0 Frequent drop>PCR
mark>SCR,MBS mark>SCR,MBS
ATM-VBR.3(nrt) PCR CDVT SCR MBS 0 Unspecified drop>PCR ATM-VBR.3(nrt) PCR CDVT SCR MBS 0 Unspecified drop>PCR
mark>SCR,MBS mark>SCR,MBS
ATM-UBR PCR CDVT - - 0 Unspecified drop>PCR ATM-UBR PCR CDVT - - 0 Unspecified drop>PCR
ATM-GFR.1 PCR CDVT MCR MBS 0 Unspecified drop>PCR ATM-GFR.1 PCR CDVT MCR MBS 0 Unspecified drop>PCR
CR-LDP Specification - 35 - Exp. August 1999
ATM-GFR.2 PCR CDVT MCR MBS 0 Unspecified drop>PCR ATM-GFR.2 PCR CDVT MCR MBS 0 Unspecified drop>PCR
mark>MCR,MFS mark>MCR,MFS
Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 33 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
int-serv-CL p m r b 0 Frequent drop>p int-serv-CL p m r b 0 Frequent drop>p
drop>r,b drop>r,b
S= User specified S= User specified
In the above table, the DS refers to a delay sensitive service where In the above table, the DS refers to a delay sensitive service where
the network commits to deliver with high probability user datagrams the network commits to deliver with high probability user datagrams
at a rate of PDR with minimum delay and delay requirements. Datagrams at a rate of PDR with minimum delay and delay requirements.
in excess of PDR will be discarded. Datagrams in excess of PDR will be discarded.
The TS refers to a generic throughput sensitive service where the The TS refers to a generic throughput sensitive service where the
network commit to deliver with high probability user datagrams at a network commits to deliver with high probability user datagrams at a
rate of at least CDR. The user may transmit at a rate higher than CDR rate of at least CDR. The user may transmit at a rate higher than
but datagrams in excess of CDR would have a lower probability of CDR but datagrams in excess of CDR would have a lower probability of
being delivered. being delivered.
The BE is the best effort service and it implies that there are no The BE is the best effort service and it implies that there are no
expected service guarantees from the network. expected service guarantees from the network.
B.2. Establishing CR-LSP Supporting Real-Time Applications B.2. Establishing CR-LSP Supporting Real-Time Applications
In this scenario the customer needs to establish an LSP for In this scenario the customer needs to establish an LSP for
supporting real-time applications such voice and video. The Delay- supporting real-time applications such voice and video. The Delay-
sensitive (DS) service is requested in this case. sensitive (DS) service is requested in this case.
The first step is the specification of the traffic parameters in the The first step is the specification of the traffic parameters in the
signaling message. The two parameters of interest to the DS service signaling message. The two parameters of interest to the DS service
are the PDR and the PBS and their values are specified by the user are the PDR and the PBS and the user based on his requirements
based on his requirements. Since all the traffic parameters are specifies their values. Since all the traffic parameters are
included in the signaling message, appropriate values must be included in the signaling message, appropriate values must be
assigned to all of them. For DS service, the CDR and the CBS values assigned to all of them. For DS service, the CDR and the CBS values
are set equal to the PDR and the PBS respectively. An indication of are set equal to the PDR and the PBS respectively. An indication of
whether the parameter values are subject to negotiation is flagged. whether the parameter values are subject to negotiation is flagged.
The transport characteristics of the DS service requires that The transport characteristics of the DS service require that
Frequent frequency to be requested to reflect the real-time delay Frequent frequency to be requested to reflect the real-time delay
requirements of the service. requirements of the service.
In addition to the transport characteristics, both the network In addition to the transport characteristics, both the network
provider and the customer need to agree on the actions enforced at provider and the customer need to agree on the actions enforced at
the edge. The specification of those actions is expected to be a part the edge. The specification of those actions is expected to be a
of the service level agreement (SLA) negotiation and is not included part of the service level agreement (SLA) negotiation and is not
in the signaling protocol. For DS service, the edge action is to drop included in the signaling protocol. For DS service, the edge action
packets that exceed the PDR and the PBS specifications. is to drop packets that exceed the PDR and the PBS specifications.
The signaling message will be sent in the direction of the ER path The signaling message will be sent in the direction of the ER path
and the LSP is established following the normal LDP procedures. Each and the LSP is established following the normal LDP procedures. Each
CR-LDP Specification - 36 - Exp. August 1999
LSR applies its admission control rules. If sufficient resources are LSR applies its admission control rules. If sufficient resources are
not available and the parameter values are subject to negotiation, not available and the parameter values are subject to negotiation,
then the LSR could negotiate down either the PDR, the PBS, or both. then the LSR could negotiate down the PDR, the PBS, or both.
The new parameters values are echoed back in the Label Mapping
Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 34 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
The new parameter values are echoed back in the Label Mapping
Message. LSRs might need to re-adjust their resource reservations Message. LSRs might need to re-adjust their resource reservations
based on the new traffic parameter values. based on the new traffic parameter values.
B.3. Establishing CR-LSP Supporting Delay Insensitive Applications B.3. Establishing CR-LSP Supporting Delay Insensitive Applications
In this example we assume that a throughput sensitive (TS) service is In this example we assume that a throughput sensitive (TS) service
requested. For resource allocation the user assigns values for PDR, is requested. For resource allocation the user assigns values for
PBS, CDR, and CBS. The negotiation flag is set if the traffic PDR, PBS, CDR, and CBS. The negotiation flag is set if the traffic
parameters are subject to negotiation. parameters are subject to negotiation.
Since the service is delay insensitive by definition, the
Unspecified frequency is signaled to indicate that the service
frequency is not an issue.
Since the service is delay insensitive by definition, the Unspecified Similar to the previous example, the edge actions are not subject
frequency is signaled to indicate that the service frequency is not for signaling and are specified in the service level agreement
an issue. between the user and the network provider.
Similar to the previous example, the edge actions are not subject for
signaling and are specified in the service level agreement between
the user and the network provider.
For TS service, the edge rules might include marking to indicate high For TS service, the edge rules might include marking to indicate
discard precedence values for all packets that exceed CDR and the high discard precedence values for all packets that exceed CDR and
CBS. The edge rules will also include dropping of packets that are do the CBS. The edge rules will also include dropping of packets that
not conform to either PDR and PBS. are do not conform to neither PDR nor PBS.
Each LSR of the LSP is expected to run its admission control rules Each LSR of the LSP is expected to run its admission control rules
and negotiate traffic parameters down if sufficient resources do not and negotiate traffic parameters down if sufficient resources do not
exist. The new parameters values are echoed back in the Label Mapping exist. The new parameter values are echoed back in the Label Mapping
Message. LSRs might need to re-adjust their resources based on the Message. LSRs might need to re-adjust their resources based on the
new traffic parameter values. new traffic parameter values.
Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 35 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
Full Copyright Statement
_Copyright c The Internet Society (date). 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.
Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 36
 End of changes. 

This html diff was produced by rfcdiff 1.23, available from http://www.levkowetz.com/ietf/tools/rfcdiff/