draft-ietf-teas-mpls-tp-rsvpte-ext-associated-lsp-03.txt   draft-ietf-teas-mpls-tp-rsvpte-ext-associated-lsp-04.txt 
TEAS Working Group Fei Zhang, Ed. TEAS Working Group Fei Zhang, Ed.
Internet-Draft Huawei Internet-Draft Huawei
Intended status: Standards Track Ruiquan Jing Intended status: Standards Track Ruiquan Jing
Expires: August 18, 2015 China Telecom Expires: August 23, 2015 China Telecom
Rakesh Gandhi, Ed. Rakesh Gandhi, Ed.
Cisco Systems Cisco Systems
February 14, 2015 February 19, 2015
RSVP-TE Extensions for Associated Bidirectional LSPs RSVP-TE Extensions for Associated Bidirectional LSPs
draft-ietf-teas-mpls-tp-rsvpte-ext-associated-lsp-03 draft-ietf-teas-mpls-tp-rsvpte-ext-associated-lsp-04
Abstract Abstract
This document describes Resource reSerVation Protocol (RSVP) This document describes Resource reSerVation Protocol (RSVP)
extensions to bind two point-to-point unidirectional Label Switched extensions to bind two point-to-point unidirectional Label Switched
Paths (LSPs) into an associated bidirectional LSP. The association Paths (LSPs) into an associated bidirectional LSP. The association
is achieved by defining new Association Types for use in ASSOCIATION is achieved by defining new Association Types for use in ASSOCIATION
and in Extended ASSOCIATION Objects. One of these types enables and in Extended ASSOCIATION Objects. One of these types enables
independent provisioning of the associated bidirectional LSPs on both independent provisioning of the associated bidirectional LSPs on both
sides, while the other enables single sided provisioning. The sides, while the other enables single sided provisioning. The
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carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions Used in This Document . . . . . . . . . . . . . . 4 2. Conventions Used in This Document . . . . . . . . . . . . . . 4
2.1. Definitions . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1. Key Word Definitions . . . . . . . . . . . . . . . . . . . 4
2.1.1. Reverse Unidirectional LSPs . . . . . . . . . . . . . 4 2.2. Reverse Unidirectional LSPs . . . . . . . . . . . . . . . 4
2.1.2. Message Formats . . . . . . . . . . . . . . . . . . . 4 2.3. Message Formats . . . . . . . . . . . . . . . . . . . . . 4
3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Provisioning Model Overview . . . . . . . . . . . . . . . 5 3.1. Provisioning Model Overview . . . . . . . . . . . . . . . 4
3.1.1. Single Sided Provisioning . . . . . . . . . . . . . . 5 3.1.1. Single Sided Provisioning . . . . . . . . . . . . . . 5
3.1.2. Double Sided Provisioning . . . . . . . . . . . . . . 5 3.1.2. Double Sided Provisioning . . . . . . . . . . . . . . 5
3.2. Association Signaling Overview . . . . . . . . . . . . . . 5 3.2. Association Signaling Overview . . . . . . . . . . . . . . 5
3.2.1. Single Sided Provisioning . . . . . . . . . . . . . . 6 3.2.1. Single Sided Provisioning . . . . . . . . . . . . . . 6
3.2.2. Double Sided Provisioning . . . . . . . . . . . . . . 6 3.2.2. Double Sided Provisioning . . . . . . . . . . . . . . 6
3.3. Asymmetric Bandwidth Signaling Overview . . . . . . . . . 7 3.3. Asymmetric Bandwidth Signaling Overview . . . . . . . . . 7
3.3.1. Single Sided Provisioning . . . . . . . . . . . . . . 7 3.3.1. Single Sided Provisioning . . . . . . . . . . . . . . 7
3.3.2. Double Sided Provisioning . . . . . . . . . . . . . . 7 3.3.2. Double Sided Provisioning . . . . . . . . . . . . . . 7
3.4. Recovery LSP Overview . . . . . . . . . . . . . . . . . . 7 3.4. Recovery LSP Overview . . . . . . . . . . . . . . . . . . 7
4. Message and Object Definitions . . . . . . . . . . . . . . . . 8 4. Message and Object Definitions . . . . . . . . . . . . . . . . 8
4.1. RSVP Message Formats . . . . . . . . . . . . . . . . . . . 8 4.1. RSVP Message Formats . . . . . . . . . . . . . . . . . . . 8
4.2. ASSOCIATION Object . . . . . . . . . . . . . . . . . . . . 8 4.2. ASSOCIATION Object . . . . . . . . . . . . . . . . . . . . 8
4.3. Extended ASSOCIATION Object . . . . . . . . . . . . . . . 9 4.3. Extended ASSOCIATION Object . . . . . . . . . . . . . . . 9
4.4. REVERSE_LSP Object Definition . . . . . . . . . . . . . . 9 4.4. REVERSE_LSP Object Definition . . . . . . . . . . . . . . 9
4.4.1. REVERSE_LSP Object Format . . . . . . . . . . . . . . 9 4.4.1. REVERSE_LSP Object Format . . . . . . . . . . . . . . 9
4.4.2. REVERSE_LSP Subobjects . . . . . . . . . . . . . . . . 10 4.4.2. REVERSE_LSP Subobjects . . . . . . . . . . . . . . . . 10
5. Processing Rules . . . . . . . . . . . . . . . . . . . . . . . 10 5. Processing Rules . . . . . . . . . . . . . . . . . . . . . . . 10
5.1. Rules For ASSOCIATION Object . . . . . . . . . . . . . . . 10 5.1. Rules For ASSOCIATION Object . . . . . . . . . . . . . . . 10
5.1.1. Compatibility For ASSOCIATION Object . . . . . . . . . 12 5.1.1. Compatibility For ASSOCIATION Object . . . . . . . . . 12
5.2. Rules For REVERSE_LSP Object . . . . . . . . . . . . . . . 13 5.2. Rules For REVERSE_LSP Object . . . . . . . . . . . . . . . 13
5.2.1. Compatibility For REVERSE_LSP Object . . . . . . . . . 13 5.2.1. Compatibility For REVERSE_LSP Object . . . . . . . . . 14
5.3. Single Sided Associated Bidirectional LSP Setup and
Teardown . . . . . . . . . . . . . . . . . . . . . . . . . 13
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
6.1. Association Types . . . . . . . . . . . . . . . . . . . . 15 6.1. Association Types . . . . . . . . . . . . . . . . . . . . 15
6.2. REVERSE_LSP Object . . . . . . . . . . . . . . . . . . . . 15 6.2. REVERSE_LSP Object . . . . . . . . . . . . . . . . . . . . 15
6.3. Reverse LSP Failure PathErr Sub-code . . . . . . . . . . . 16 6.3. Reverse LSP Failure PathErr Sub-code . . . . . . . . . . . 16
7. Security Considerations . . . . . . . . . . . . . . . . . . . 16 7. Security Considerations . . . . . . . . . . . . . . . . . . . 16
8. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 16 8. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 16
9. Contributing Authors . . . . . . . . . . . . . . . . . . . . . 17 9. Contributing Authors . . . . . . . . . . . . . . . . . . . . . 17
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 18 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 18
10.1. Normative References . . . . . . . . . . . . . . . . . . 18 10.1. Normative References . . . . . . . . . . . . . . . . . . 18
10.2. Informative References . . . . . . . . . . . . . . . . . 18 10.2. Informative References . . . . . . . . . . . . . . . . . 18
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to the [RFC4872] defined ASSOCIATION Objects and the [RFC6780] to the [RFC4872] defined ASSOCIATION Objects and the [RFC6780]
defined the Extended ASSOCIATION Objects collectively as the defined the Extended ASSOCIATION Objects collectively as the
(Extended) ASSOCIATION Objects. (Extended) ASSOCIATION Objects.
This document specifies mechanisms for binding two reverse This document specifies mechanisms for binding two reverse
unidirectional LSPs into an associated bidirectional LSP. The unidirectional LSPs into an associated bidirectional LSP. The
association is achieved by defining new Association Types for use in association is achieved by defining new Association Types for use in
(Extended) ASSOCIATION Objects. One of these types enables (Extended) ASSOCIATION Objects. One of these types enables
independent provisioning of the associated bidirectional LSPs, while independent provisioning of the associated bidirectional LSPs, while
the other enables single sided provisioning. The REVERSE_LSP Object the other enables single sided provisioning. The REVERSE_LSP Object
is also defined to enable a single endpoint to specify all the is also defined to enable a single endpoint to specify any parameter
parameters of an associated LSP in the single sided provisioning of an associated LSP in the single sided provisioning case. For
case. For example, the REVERSE_LSP Object allow asymmetric upstream example, the REVERSE_LSP Object allow asymmetric upstream and
and downstream bandwidths for the associated bidirectional LSP. downstream bandwidths for the associated bidirectional LSP.
2. Conventions Used in This Document 2. Conventions Used in This Document
2.1. Key Word Definitions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
2.1. Definitions 2.2. Reverse Unidirectional LSPs
2.1.1. Reverse Unidirectional LSPs
Two reverse unidirectional LSPs are setup in the opposite directions Two reverse unidirectional LSPs are setup in the opposite directions
between a pair of source and destination nodes to form an associated between a pair of source and destination nodes to form an associated
bidirectional LSP. A reverse unidirectional LSP originates on the bidirectional LSP. A reverse unidirectional LSP originates on the
same node where the forward unidirectional LSP terminates, and it same node where the forward unidirectional LSP terminates, and it
terminates on the same node where the forward unidirectional LSP terminates on the same node where the forward unidirectional LSP
originates. originates.
2.1.2. Message Formats 2.3. Message Formats
This document uses the Routing Backus-Naur Form (RBNF) to define This document uses the Routing Backus-Naur Form (RBNF) to define
message formats as defined in [RFC5511]. message formats as defined in [RFC5511].
3. Overview 3. Overview
3.1. Provisioning Model Overview 3.1. Provisioning Model Overview
This section provides an overview and definition of the models for This section provides an overview and definition of the models for
provisioning associated bidirectional LSPs. provisioning associated bidirectional LSPs.
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can be provided at one or both endpoints of the associated can be provided at one or both endpoints of the associated
bidirectional LSP. Depending on the method chosen, there are two bidirectional LSP. Depending on the method chosen, there are two
models of creating an associated bidirectional LSP; single sided models of creating an associated bidirectional LSP; single sided
provisioning, and double sided provisioning. provisioning, and double sided provisioning.
3.1.1. Single Sided Provisioning 3.1.1. Single Sided Provisioning
For the single sided provisioning, the Traffic Engineering (TE) For the single sided provisioning, the Traffic Engineering (TE)
tunnel is configured only on one endpoint. An LSP for this tunnel is tunnel is configured only on one endpoint. An LSP for this tunnel is
initiated by the initiating endpoint with the (Extended) ASSOCIATION initiated by the initiating endpoint with the (Extended) ASSOCIATION
Object inserted in the Path message. The other endpoint then creates and REVERSE_LSP Objects inserted in the Path message. The other
the corresponding reverse TE tunnel and signals the reverse LSP in endpoint then creates the corresponding reverse TE tunnel and signals
response using information from the REVERSE_LSP Object if present. the reverse LSP in response using information from the REVERSE_LSP
Object and other Objects present in the received Path message.
3.1.2. Double Sided Provisioning 3.1.2. Double Sided Provisioning
For the double sided provisioning, two unidirectional TE tunnels are For the double sided provisioning, two unidirectional TE tunnels are
configured independently, one on each endpoint. The LSPs for the configured independently, one on each endpoint. The LSPs for the
tunnels are signaled with (Extended) ASSOCIATION Objects inserted in tunnels are signaled with (Extended) ASSOCIATION Objects inserted in
the Path message by both endpoints to indicate that the two LSPs are the Path message by both endpoints to indicate that the two LSPs are
to be associated to form a bidirectional LSP. to be associated to form a bidirectional LSP.
3.2. Association Signaling Overview 3.2. Association Signaling Overview
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C C
Figure 1: An example of associated bidirectional LSP Figure 1: An example of associated bidirectional LSP
3.2.1. Single Sided Provisioning 3.2.1. Single Sided Provisioning
For the single sided provisioning model, creation of reverse LSP1 is For the single sided provisioning model, creation of reverse LSP1 is
triggered by LSP2 or creation of reverse LSP2 is triggered by LSP1. triggered by LSP2 or creation of reverse LSP2 is triggered by LSP1.
When creation of reverse LSP2 is triggered by LSP1, LSP1 is When creation of reverse LSP2 is triggered by LSP1, LSP1 is
provisioned first (or refreshed if LSP1 already exists) at node A. provisioned first (or refreshed if LSP1 already exists) at node A.
LSP1 is then signaled with an (Extended) ASSOCIATION Object inserted LSP1 is then signaled with an (Extended) ASSOCIATION and REVERSE_LSP
in the Path message, in which the Association Type indicating single Objects inserted in the Path message. The Association Type indicates
sided provisioning is included. Upon receiving this Path message for single sided provisioning. Upon receiving this Path message for
LSP1, node B establishes reverse LSP2. The (Extended) ASSOCIATION LSP1, node B establishes reverse LSP2. The (Extended) ASSOCIATION
Object inserted in LSP2's Path message is the same as that received Object inserted in LSP2's Path message is the same as that received
in LSP1's Path message. in LSP1's Path message.
A similar procedure is used if LSP2 is provisioned first at node B A similar procedure is used if LSP2 is provisioned first at node B
and the creation of reverse LSP1 at node A is either triggered by and the creation of reverse LSP1 at node A is either triggered by
LSP2 or the reverse LSP1 existed. In all three scenarios, the two LSP2 or the reverse LSP1 existed. In all three scenarios, the two
unidirectional LSPs are bound together to form an associated unidirectional LSPs are bound together to form an associated
bidirectional LSP based on identical (Extended) ASSOCIATION Objects bidirectional LSP based on identical (Extended) ASSOCIATION Objects
in the two LSPs' Path messages. in the two LSPs' Path messages.
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3.3. Asymmetric Bandwidth Signaling Overview 3.3. Asymmetric Bandwidth Signaling Overview
This section provides an overview of the methods for signaling This section provides an overview of the methods for signaling
asymmetric upstream and downstream bandwidths for the associated asymmetric upstream and downstream bandwidths for the associated
bidirectional LSPs. bidirectional LSPs.
3.3.1. Single Sided Provisioning 3.3.1. Single Sided Provisioning
A new REVERSE_LSP Object for use in the single sided provisioning A new REVERSE_LSP Object for use in the single sided provisioning
model is defined in this document, in Section 4.4. When the single model is defined in this document, in Section 4.4. When the single
sided provisioning model is used, a SENDER_TSPEC object can be added sided provisioning model is used, a SENDER_TSPEC Object can be added
in the REVERSE_LSP Object as a subobject in the initiating LSP's Path in the REVERSE_LSP Object as a subobject in the initiating LSP's Path
message to specify a different bandwidth for the reverse LSP. As message to specify a different bandwidth for the reverse LSP. As
described in Section 4.4, addition of the REVERSE_LSP Object also described in Section 4.4, addition of the REVERSE_LSP Object also
allows the initiating node to control other aspects of the reverse allows the initiating node to control other aspects of the reverse
LSP (such as its path) by including other existing objects in a LSP (such as its path) by including other Objects in a REVERSE_LSP
REVERSE_LSP Object. Object.
Consider again the topology described in Figure 1, where the creation Consider again the topology described in Figure 1, where the creation
of reverse LSP2 is triggered by LSP1. Node A signals LSP1 with the of reverse LSP2 is triggered by LSP1. Node A signals LSP1 with the
(Extended) ASSOCIATION Object with Association Type indicating single (Extended) ASSOCIATION Object with Association Type indicating single
sided provisioning and inserts a SENDER_TSPEC subobject for use by sided provisioning and inserts a SENDER_TSPEC subobject for use by
LSP2 in the REVERSE_LSP Object in the Path message. Node B then LSP2 in the REVERSE_LSP Object in the Path message. Node B then
establishes the LSP2 in the reverse direction using the asymmetric establishes the LSP2 in the reverse direction using the asymmetric
bandwidth thus specified by LSP1 and allows node A to control the bandwidth thus specified by LSP1 and allows node A to control the
reverse LSP2. reverse LSP2.
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Extended Association ID: Extended Association ID:
For both single sided and double sided provisioning, Extended For both single sided and double sided provisioning, Extended
Association ID, when used, MUST be set to a value selected by the Association ID, when used, MUST be set to a value selected by the
node that originates the association for the bidirectional LSP. node that originates the association for the bidirectional LSP.
4.4. REVERSE_LSP Object Definition 4.4. REVERSE_LSP Object Definition
4.4.1. REVERSE_LSP Object Format 4.4.1. REVERSE_LSP Object Format
The information of the reverse LSP is specified via the REVERSE_LSP The REVERSE_LSP Object is used to carry information to be used by the
Object. This is an optional object carried in a Path message with reverse LSP. The object also indicates that the LSP is the forward
Class Number in the form 11bbbbbb and has the following format: LSP of a single sided provisioned associated bidirectional LSP.
The Object has the following format:
Class_Num = 203, C_Type = 1. Class_Num = 203, C_Type = 1.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
// (Subobjects) // // (Subobjects) //
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4.4.2. REVERSE_LSP Subobjects 4.4.2. REVERSE_LSP Subobjects
The contents of a REVERSE_LSP Object is a variable length series of Subobjects are used to override the default contents of Path message
subobjects and have the same format as RSVP Objects, see Section of a Reverse LSP, see Section 5.2. The contents of a REVERSE_LSP
3.1.2 of [RFC2205]. The subobjects permitted in the REVERSE_LSP Object is zero or more variable length subobjects that have the same
Object are previously defined as Path message Objects, and have the format as RSVP Objects, see Section 3.1.2 of [RFC2205]. Any Object
same order in the REVERSE_LSP Object. that may be carried in a Path message MAY be carried in the
REVERSE_LSP Object. Subobject ordering MUST follow any Path message
Object ordering requirements.
Examples of the Path message objects carried in the REVERSE_LSP Examples of the Path message objects that can be carried in the
Object are (but not limited to): REVERSE_LSP Object are (but not limited to):
- SENDER_TSPEC [RFC2205] - SENDER_TSPEC [RFC2205]
- EXPLICIT_ROUTE Object (ERO) [RFC3209] - EXPLICIT_ROUTE Object (ERO) [RFC3209]
- SESSION_ATTRIBUTE Object [RFC3209] - SESSION_ATTRIBUTE Object [RFC3209]
- ADMIN_STATUS Object [RFC3473] - ADMIN_STATUS Object [RFC3473]
- LSP_REQUIRED_ATTRIBUTES Object [RFC5420] - LSP_REQUIRED_ATTRIBUTES Object [RFC5420]
- PROTECTION Object [RFC3473] [RFC4872] - PROTECTION Object [RFC3473] [RFC4872]
5. Processing Rules 5. Processing Rules
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in this document are only to be interpreted in Path Messages. These in this document are only to be interpreted in Path Messages. These
types SHOULD NOT be used in ASSOCIATION Objects carried in Resv types SHOULD NOT be used in ASSOCIATION Objects carried in Resv
messages and SHOULD be ignored if present. messages and SHOULD be ignored if present.
To indicate an associated bidirectional LSP, an ingress node MUST To indicate an associated bidirectional LSP, an ingress node MUST
insert an (Extended) ASSOCIATION Object into the Path message of the insert an (Extended) ASSOCIATION Object into the Path message of the
unidirectional LSP that is part of the associated bidirectional LSP unidirectional LSP that is part of the associated bidirectional LSP
it initiates. If either Global Association Source or Extended it initiates. If either Global Association Source or Extended
Association Address is required, then an Extended ASSOCIATION Object Association Address is required, then an Extended ASSOCIATION Object
[RFC6780] MUST be inserted in the Path message. Otherwise, an [RFC6780] MUST be inserted in the Path message. Otherwise, an
ASSOCIATION Object MAY be used. Only one (Extended) ASSOCIATION ASSOCIATION Object MAY be used. (Extended) ASSOCIATION Objects with
Object with the Association Types defined in this document SHOULD be both single sided and double sided Association Types MUST NOT be
included by an ingress node in an outgoing Path message. (Extended) added or sent in the same Path message.
ASSOCIATION Objects with both single sided and double sided
Association Types MUST NOT be added in the same Path message.
The ingress node MUST set the Association Type field in the The ingress node MUST set the Association Type field in the
(Extended) ASSOCIATION Object to "Single Sided Associated (Extended) ASSOCIATION Object to "Single Sided Associated
Bidirectional LSP" when single sided provisioning is used, and to Bidirectional LSP" when single sided provisioning is used, and to
"Double Sided Associated Bidirectional LSP" when double sided "Double Sided Associated Bidirectional LSP" when double sided
provisioning is used. provisioning is used.
A transit node MAY identify the unidirectional LSPs of an associated A transit node MAY identify the unidirectional LSPs of an associated
bidirectional LSP based on (Extended) ASSOCIATION Objects, with the bidirectional LSP based on (Extended) ASSOCIATION Objects, with the
Association Type values defined in this document, carried in Path Association Type values defined in this document, carried in Path
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Egress nodes which support the Association Types defined in this Egress nodes which support the Association Types defined in this
document identify the unidirectional LSPs of an associated document identify the unidirectional LSPs of an associated
bidirectional LSP based on (Extended) ASSOCIATION Objects carried in bidirectional LSP based on (Extended) ASSOCIATION Objects carried in
Path messages. Note that an ingress node will normally be the Path messages. Note that an ingress node will normally be the
ingress for one of the unidirectional LSPs that make up an associated ingress for one of the unidirectional LSPs that make up an associated
bidirectional LSP. When an egress node receives a Path message bidirectional LSP. When an egress node receives a Path message
containing an (Extended) ASSOCIATION Object with one of the containing an (Extended) ASSOCIATION Object with one of the
Association Types defined in this document, it MUST attempt to Association Types defined in this document, it MUST attempt to
identify other LSPs (including ones for which it is an ingress node) identify other LSPs (including ones for which it is an ingress node)
with which the LSP being processed is associated. As defined above, with which the LSP being processed is associated. As defined above,
such associations are made per the rules defined in [RFC6780]. If such associations are made per the rules defined in [RFC6780]. An
the egress node does not support the Association Types defined in LSP not being associated at the time of signaling (for example,
this document, it MUST return a PathErr with Error Code "Admission during rerouting or re-optimization) on an egress node is not
Control Failure (01) [RFC2205]" and Sub-code "Bad Association Type necessarily considered an error condition.
(5) [RFC4872]". An LSP not being associated at the time of signaling
(for example, during rerouting or re-optimization) on an egress node
is not necessarily considered an error condition.
Associated bidirectional LSP teardown follows the standard procedures Associated bidirectional LSP teardown follows the standard procedures
defined in [RFC3209] and [RFC3473] either without or with the defined in [RFC3209] and [RFC3473] either without or with the
administrative status. Generally, the teardown procedures of the administrative status. Generally, the teardown procedures of the
unidirectional LSPs forming an associated bidirectional LSP are unidirectional LSPs forming an associated bidirectional LSP are
independent of each other, so it is possible that while one LSP independent of each other, so it is possible that while one LSP
follows graceful teardown with administrative status, the reverse LSP follows graceful teardown with administrative status, the reverse LSP
is torn down without administrative status (using is torn down without administrative status (using
PathTear/ResvTear/PathErr with state removal). See Section 5.3 below PathTear/ResvTear/PathErr with state removal). See Section 5.2 below
for additional rules related to LSPs established using single sided for additional rules related to LSPs established using single sided
provisioning. provisioning.
When an LSP signaled with a Path message containing an (Extended) When an LSP signaled with a Path message containing an (Extended)
ASSOCIATION Object with an Association Type defined in this document ASSOCIATION Object with an Association Type defined in this document
is torn down, the processing node SHALL remove the binding of the LSP is torn down, the processing node SHALL remove the binding of the LSP
to any previously identified associated bidirectional LSP. to any previously identified associated bidirectional LSP.
No additional processing is needed for Path messages with an No additional processing is needed for Path messages with an
(Extended) ASSOCIATION Object containing an Association Type field of (Extended) ASSOCIATION Object containing an Association Type field of
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The ASSOCIATION Object has been defined in [RFC4872] and the Extended The ASSOCIATION Object has been defined in [RFC4872] and the Extended
ASSOCIATION Object has been defined in [RFC6780], both with class ASSOCIATION Object has been defined in [RFC6780], both with class
numbers in the form 11bbbbbb, which ensures compatibility with numbers in the form 11bbbbbb, which ensures compatibility with
non-supporting nodes. Per [RFC2205], such nodes will ignore the non-supporting nodes. Per [RFC2205], such nodes will ignore the
object but forward it without modification. object but forward it without modification.
Operators wishing to use a function supported by a particular Operators wishing to use a function supported by a particular
association type SHOULD ensure that the type is supported on any node association type SHOULD ensure that the type is supported on any node
that is expected to act on the association [RFC6780]. that is expected to act on the association [RFC6780].
An egress node that does not support the Association Types defined in
this document, is expected to return a PathErr with Error Code
"Admission Control Failure (01) [RFC2205]" and Sub-code "Bad
Association Type (5) [RFC4872]".
LSP recovery as defined in [RFC4872] and [RFC4873] is not impacted by LSP recovery as defined in [RFC4872] and [RFC4873] is not impacted by
this document. The recovery mechanisms defined in [RFC4872] and this document. The recovery mechanisms defined in [RFC4872] and
[RFC4873] rely on the use of the (Extended) ASSOCIATION Objects, but [RFC4873] rely on the use of the (Extended) ASSOCIATION Objects, but
use a different value for Association Type; multiple ASSOCIATION use a different value for Association Type; multiple ASSOCIATION
Objects can be present in the LSP Path message and can coexist with Objects can be present in the LSP Path message and can coexist with
the procedures defined in this document. the procedures defined in this document.
5.2. Rules For REVERSE_LSP Object 5.2. Rules For REVERSE_LSP Object
A node initiating a Path message containing an ASSOCIATION or A node initiating a Path message containing an ASSOCIATION or
Extended ASSOCIATION Object with the Association Type set to "Single Extended ASSOCIATION Object with the Association Type set to "Single
Sided Associated Bidirectional LSP" MUST include a REVERSE_LSP Object Sided Associated Bidirectional LSP" MUST include a REVERSE_LSP Object
in the Path message of the LSP when it wishes to control the reverse in the Path message of the LSP.
LSP originating on the other endpoint node.
The REVERSE_LSP subobject MAY contain any of the specified objects The REVERSE_LSP subobject MAY contain any of object that the
which the initiating node desires to have included in the Path initiating node desires to have included in the Path message for the
message for the associated reverse LSP. The REVERSE_LSP Object MUST associated reverse LSP. The REVERSE_LSP Object SHOULD NOT be
NOT be included in a REVERSE_LSP Object. included in a REVERSE_LSP Object.
A node receiving a valid Path message containing a REVERSE_LSP Object A transit node receiving a valid Path message containing a
that is not the egress node for the LSP being signaled MUST forward REVERSE_LSP Object MUST forward the REVERSE_LSP Object unchanged in
the REVERSE_LSP Object unchanged in the outgoing Path message. the outgoing Path message.
An egress node, upon receiving a Path message containing an An egress node, upon receiving a Path message containing an
REVERSE_LSP Object MUST verify that the Path message contains an REVERSE_LSP Object MUST verify that the Path message contains an
ASSOCIATION or Extended ASSOCIATION object with the Association Type ASSOCIATION or Extended ASSOCIATION Object with the Association Type
set to "Single Sided Associated Bidirectional LSP". If it does not, set to "Single Sided Associated Bidirectional LSP". If it does not,
the Path message MUST NOT trigger a reverse LSP. This verification the Path message MUST NOT trigger a reverse LSP. This verification
failure SHOULD NOT trigger any RSVP message but can be logged failure SHOULD NOT trigger any RSVP message but can be logged
locally, and perhaps reported through network management mechanisms. locally, and perhaps reported through network management mechanisms.
Once validated, the egress node MUST use the subobjects contained in Once validated, the egress node MUST create an LSP in the reverse
any present REVERSE_LSP Objects in the management of the reverse LSP direction or reject the Path message. If the creation of a reverse
described in the previous section. Note that the contents of a LSP fails, the egress node MUST return a PathErr with Error code
REVERSE_LSP Object may change over the life of an LSP and such "Admission Control Failure (01) [RFC2205]" and Sub-code "Reverse LSP
changes MUST result in corresponding changes in the reverse LSP. An Failure" defined in this document. Note that normal Resv processing
addition or removal of the REVERSE_LSP Object in the received Path SHOULD NOT be impacted by the presence of an ASSOCIATION Object with
message may cause an egress node to teardown and reestablish a new an Association Type set to "Single Sided Associated Bidirectional
reverse LSP, or trigger re-optimization or in-place modification of LSP".
the LSP (which may depend on the local policy).
5.2.1. Compatibility For REVERSE_LSP Object
The REVERSE_LSP Object is defined with class numbers in the form
11bbbbbb, which ensures compatibility with non-supporting nodes. Per
[RFC2205], such nodes will ignore the object but forward it without
modification.
5.3. Single Sided Associated Bidirectional LSP Setup and Teardown
An egress node, upon receiving a Path message containing an
ASSOCIATION or Extended ASSOCIATION Object with Association Type set
to "Single Sided Associated Bidirectional LSP" and containing a
REVERSE_LSP Object MUST create an LSP in the reverse direction or
reject the Path message. If the creation of a reverse LSP fails, the
egress node MUST return a PathErr with Error code "Admission Control
Failure (01) [RFC2205]" and Sub-code "Reverse LSP Failure" defined in
this document. Note that normal Resv processing SHOULD NOT be
impacted by the presence of an ASSOCIATION Object with an Association
Type set to "Single Sided Associated Bidirectional LSP".
The egress node MUST use the subobjects contained in the REVERSE_LSP The egress node MUST use the subobjects contained in the REVERSE_LSP
Object for initiating the reverse LSP as described in Section 5.2. Object for initiating the reverse LSP. When a subobject is not
When a subobject is not present in the received REVERSE_LSP Object, present in the received REVERSE_LSP Object, the egress node SHOULD
the egress node SHOULD initiate a reverse LSP based on the initiate the reverse LSP based on the information contained in the
information contained in the received Path message of the forward LSP received Path message of the forward LSP as follows:
as following:
o The egress node SHOULD copy the information from the received o The egress node SHOULD copy the information from the received
SESSION_ATTRIBUTE, CLASS_TYPE, LABEL_REQUEST, ASSOCIATION, SESSION_ATTRIBUTE, CLASS_TYPE, LABEL_REQUEST, ASSOCIATION,
ADMIN_STATUS and PROTECTION Objects in the forward LSP Path message ADMIN_STATUS and PROTECTION Objects in the forward LSP Path message
to form the Path message of the reverse LSP when the object is not to form the Path message of the reverse LSP when the object is not
present in the received REVERSE_LSP Object. present in the received REVERSE_LSP Object.
o The IP address in the reverse LSP's SESSION Object SHOULD be set o The IP address in the reverse LSP's SESSION Object SHOULD be set
to the IP address carried in the received SENDER_TEMPLATE Object, and to the IP address carried in the received SENDER_TEMPLATE Object, and
conversely the IP address in the SENDER_TEMPLATE object SHOULD be set conversely the IP address in the SENDER_TEMPLATE Object SHOULD be set
to the IP address carried in the received SESSION Object. There are to the IP address carried in the received SESSION Object. There are
no additional requirements related to the IDs carried in the SESSION no additional requirements related to the IDs carried in the SESSION
and SENDER_TEMPLATE Objects. and SENDER_TEMPLATE Objects.
o When the forward LSP Path message contains a RECORD_ROUTE Object, o When the forward LSP Path message contains a RECORD_ROUTE Object,
the egress node SHOULD include the received RECORD_ROUTE Object in the egress node SHOULD include the received RECORD_ROUTE Object in
the reverse LSP Path message. Local node information SHOULD also be the reverse LSP Path message. Local node information SHOULD also be
recorded per Standard Path message processing. recorded per Standard Path message processing.
o There are no specific requirements related to other objects. o There are no specific requirements related to other objects.
The resulting Path message is used to create the reverse LSP. From The resulting Path message is used to create the reverse LSP. From
this point on, Standard Path message processing is used in processing this point on, Standard Path message processing is used in processing
the resulting Path message. In this case, changes to the received the resulting Path message.
Path messages can result in changes to the reverse LSP. In
particular, any object that was copied as part of initial Path
message creation MUST be copied when modified.
When the egress node receives a PathTear message, the node MUST Note that the contents of a forward LSP, including a carried
remove the associated reverse LSP using Standard PathTear message REVERSE_LSP Object, may change over the life of an LSP and such
processing. Tear down of the reverse LSP for other reasons SHOULD changes MUST result in corresponding changes in the reverse LSP. In
NOT trigger removal of the initiating LSP, but SHOULD result in the particular, any object or subobject that was copied during the
egress node sending a PathErr with Error code "Admission Control creation of the initial reverse LSP's Path message MUST be copied
Failure (01) [RFC2205]" and Sub-code "Reverse LSP Failure" defined in when modified in the forward LSP, and a trigger Path message MUST be
this document. processed.
The removal of the REVERSE_LSP Object in the received Path message
SHOULD cause the egress node to teardown any previously established
reverse LSP.
When the egress node receives a PathTear message for the forward LSP,
the node MUST remove the associated reverse LSP using Standard
PathTear message processing. Tear down of the reverse LSP for other
reasons SHOULD NOT trigger removal of the initiating LSP, but SHOULD
result in the egress node sending a PathErr with Error code
"Admission Control Failure (01) [RFC2205]" and Sub-code "Reverse LSP
Failure" defined in this document.
5.2.1. Compatibility For REVERSE_LSP Object
The REVERSE_LSP Object is defined with class numbers in the form
11bbbbbb, which ensures compatibility with non-supporting nodes. Per
[RFC2205], such nodes will ignore the object but forward it without
modification.
6. IANA Considerations 6. IANA Considerations
IANA is requested to administer assignment of new values for IANA is requested to administer assignment of new values for
namespace defined in this document and summarized in this section. namespace defined in this document and summarized in this section.
6.1. Association Types 6.1. Association Types
IANA maintains the "Generalized Multi-Protocol Label Switching IANA maintains the "Generalized Multi-Protocol Label Switching
(GMPLS) Signaling Parameters" registry (see (GMPLS) Signaling Parameters" registry (see
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