CCAMP Working Group Fei Zhang, Ed.
Internet-Draft Huawei
Intended status: Standards Track Ruiquan Jing
Expires: June 11, 2015 China Telecom
Rakesh Gandhi, Ed.
Cisco Systems
December 8, 2014
RSVP-TE Extensions for Associated Bidirectional LSPs
draft-ietf-teas-mpls-tp-rsvpte-ext-associated-lsp-00
Abstract
This document describes Resource reSerVation Protocol (RSVP)
extensions to bind two point-to-point unidirectional Label Switched
Paths (LSPs) into an associated bidirectional LSP. The association
is achieved by defining new Association Types for use in ASSOCIATION
and in Extended ASSOCIATION Objects. One of these types enables
independent provisioning of the associated bidirectional LSPs on both
sides, while the other enables single sided provisioning. The
REVERSE_LSP Object is also defined to enable a single endpoint to
specify all the parameters of an associated LSP in the single sided
provisioning case.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
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publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions Used in This Document . . . . . . . . . . . . . . 4
2.1. Definitions . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1.1. Reverse Unidirectional LSPs . . . . . . . . . . . . . 4
3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Provisioning Model Overview . . . . . . . . . . . . . . . 4
3.1.1. Single Sided Provisioning . . . . . . . . . . . . . . 5
3.1.2. Double Sided Provisioning . . . . . . . . . . . . . . 5
3.2. Association Signaling Overview . . . . . . . . . . . . . . 5
3.2.1. Single Sided Provisioning . . . . . . . . . . . . . . 6
3.2.2. Double Sided Provisioning . . . . . . . . . . . . . . 6
3.3. Asymmetric Bandwidth Signaling Overview . . . . . . . . . 6
3.3.1. Single Sided Provisioning . . . . . . . . . . . . . . 6
3.3.2. Double Sided Provisioning . . . . . . . . . . . . . . 7
3.4. Recovery LSP Overview . . . . . . . . . . . . . . . . . . 7
4. Message and Object Definitions . . . . . . . . . . . . . . . . 7
4.1. RSVP Message Formats . . . . . . . . . . . . . . . . . . . 7
4.2. ASSOCIATION Object . . . . . . . . . . . . . . . . . . . . 8
4.3. Extended ASSOCIATION Object . . . . . . . . . . . . . . . 9
4.4. REVERSE_LSP Object Definition . . . . . . . . . . . . . . 9
4.4.1. REVERSE_LSP Object Format . . . . . . . . . . . . . . 9
4.4.2. REVERSE_LSP Subobjects . . . . . . . . . . . . . . . . 10
5. Processing Rules . . . . . . . . . . . . . . . . . . . . . . . 10
5.1. Rules For ASSOCIATION Object . . . . . . . . . . . . . . . 10
5.1.1. Compatibility For ASSOCIATION Object . . . . . . . . . 12
5.2. Rules For REVERSE_LSP Object . . . . . . . . . . . . . . . 12
5.2.1. Compatibility For REVERSE_LSP Object . . . . . . . . . 13
5.3. Single Sided Associated Bidirectional LSP Setup and
Teardown . . . . . . . . . . . . . . . . . . . . . . . . . 13
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
6.1. Association Types . . . . . . . . . . . . . . . . . . . . 14
6.2. REVERSE_LSP Object . . . . . . . . . . . . . . . . . . . . 14
7. Security Considerations . . . . . . . . . . . . . . . . . . . 15
8. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 15
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16
9.1. Normative References . . . . . . . . . . . . . . . . . . . 16
9.2. Informative References . . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18
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1. Introduction
The MPLS Transport Profile (MPLS-TP) requirements document [RFC5654]
specifies that MPLS-TP MUST support associated bidirectional point-
to-point Label Switched Paths (LSPs). These requirements are given
in Section 2.1 (General Requirements), and are repeated below:
7. MPLS-TP MUST support associated bidirectional point-to-point
LSPs.
11. The end points of an associated bidirectional LSP MUST be aware
of the pairing relationship of the forward and reverse LSPs used to
support the bidirectional service.
12. Nodes on the LSP of an associated bidirectional LSP where both
the forward and backward directions transit the same node in the same
(sub)layer as the LSP SHOULD be aware of the pairing relationship of
the forward and the backward directions of the LSP.
50. The MPLS-TP control plane MUST support establishing associated
bidirectional P2P LSP including configuration of protection functions
and any associated maintenance functions.
The above requirements are also repeated in [RFC6373].
Furthermore, an associated bidirectional LSP is also useful for
protection switching for Operations, Administrations and Maintenance
(OAM) messages that require a return path.
A variety of applications, such as Internet services and the return
paths of OAM messages, exist and which may have different upstream
and downstream bandwidth requirements. [RFC5654] specifies an
asymmetric bandwidth requirement in Section 2.1 (General
Requirements), and is repeated below:
14. MPLS-TP MUST support bidirectional LSPs with asymmetric
bandwidth requirements, i.e., the amount of reserved bandwidth
differs between the forward and backward directions.
The approach for supporting asymmetric bandwidth co-routed
bidirectional LSPs is defined in [RFC6387].
The method of association and the corresponding Resource reSerVation
Protocol (RSVP) ASSOCIATION Object are defined in [RFC4872],
[RFC4873] and [RFC6689]. In that context, the ASSOCIATION Object is
used to associate a recovery LSP with the LSP it is protecting. This
object also has broader applicability as a mechanism to associate
RSVP states. [RFC6780] defines the Extended ASSOCIATION Objects that
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can be more generally applied for this purpose. This document refers
to the [RFC4872] defined ASSOCIATION Objects and the [RFC6780]
defined the Extended ASSOCIATION Objects collectively as the
(Extended) ASSOCIATION Objects.
This document specifies mechanisms for binding two reverse
unidirectional LSPs into an associated bidirectional LSP. The
association is achieved by defining new Association Types for use in
(Extended) ASSOCIATION Objects. One of these types enables
independent provisioning of the associated bidirectional LSPs, while
the other enables single sided provisioning. The REVERSE_LSP Object
is also defined to enable a single endpoint to specify all the
parameters of an associated LSP in the single sided provisioning
case. For example, the REVERSE_LSP Object allow asymmetric upstream
and downstream bandwidths for the associated bidirectional LSP.
2. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
2.1. Definitions
2.1.1. Reverse Unidirectional LSPs
Two reverse unidirectional LSPs are setup in the opposite directions
between a pair of source and destination nodes to form an associated
bidirectional LSP. A reverse unidirectional LSP originates on the
same node where the forward unidirectional LSP terminates, and it
terminates on the same node where the forward unidirectional LSP
originates.
3. Overview
3.1. Provisioning Model Overview
This section provides an overview and definition of the models for
provisioning bidirectional LSPs.
The associated bidirectional LSP's forward and reverse unidirectional
LSPs are established, monitored, and protected independently as
specified by [RFC5654]. Configuration information regarding the LSPs
can be provided at one or both endpoints of the associated
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bidirectional LSP. Depending on the method chosen, there are two
models of creating an associated bidirectional LSP; single sided
provisioning, and double sided provisioning.
3.1.1. Single Sided Provisioning
For the single sided provisioning, the Traffic Engineering (TE)
tunnel is configured only on one endpoint. An LSP for this tunnel is
initiated by the initiating endpoint with the (Extended) ASSOCIATION
Object inserted in the Path message. The other endpoint then creates
the corresponding reverse TE tunnel and signals the reverse LSP in
response.
3.1.2. Double Sided Provisioning
For the double sided provisioning, two unidirectional TE tunnels are
configured independently on both endpoints. The LSPs for the tunnels
are signaled with (Extended) ASSOCIATION Objects inserted in the Path
message by both endpoints to indicate that the two LSPs are to be
associated to form a bidirectional LSP.
3.2. Association Signaling Overview
This section provides an overview of the association signaling
methods for the bidirectional LSPs.
Three scenarios exist for binding two unidirectional LSPs together to
form an associated bidirectional LSP. These are: 1) Neither
unidirectional LSP exists, and both must be established. 2) Both
unidirectional LSPs exist, but the association must be established.
3) One LSP exists, but the reverse associated LSP must be
established.
In each of the situations described above, both provisioning models
are applicable.
Path Computation Element (PCE)-based approaches [RFC4655], may be
used for path computation of an associated bidirectional LSP.
However, these approaches are outside the scope of this document.
Consider the topology described in Figure 1 (an example of associated
bidirectional LSP). LSP1 from A to B, takes the path A,D,B and LSP2
from B to A takes the path B,D,C,A. These two LSPs, once established
and associated, form an associated bidirectional LSP between node A
and node B.
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LSP1 -->
A-------D-------B
\ / <-- LSP2
\ /
\ /
C
Figure 1: An example of associated bidirectional LSP
3.2.1. Single Sided Provisioning
For the single sided provisioning model, creation of reverse LSP1 is
triggered by LSP2 or creation of reverse LSP2 is triggered by LSP1.
When creation of reverse LSP2 is triggered by LSP1, LSP1 is
provisioned first (or refreshed if LSP1 already exists) at node A.
LSP1 is then signaled with an (Extended) ASSOCIATION Object inserted
in the Path message, in which the Association Type indicating single
sided provisioning. Upon receiving this Path message for LSP1, node
B establishes reverse LSP2. The (Extended) ASSOCIATION Object
inserted in LSP2's Path message is the same as that received in
LSP1's Path message.
A similar procedure is used if LSP2 is provisioned first at node B
and the creation of reverse LSP1 is triggered by LSP2. In both
cases, the two unidirectional LSPs are bound together to form an
associated bidirectional LSP based on identical (Extended)
ASSOCIATION Objects in the two LSPs' Path messages.
3.2.2. Double Sided Provisioning
For the double sided provisioning model, both LSP1 and LSP2 are
signaled independently with (Extended) ASSOCIATION Object inserted in
the Path message, in which the Association Type indicating double
sided provisioning. In this case, the two unidirectional LSPs are
bound together to form an associated bidirectional LSP based on
identical (Extended) ASSOCIATION Objects in the two LSPs' Path
messages.
3.3. Asymmetric Bandwidth Signaling Overview
This section provides an overview of the methods for signaling
asymmetric upstream and downstream bandwidths for the associated
bidirectional LSPs.
3.3.1. Single Sided Provisioning
A new REVERSE_LSP Object for use in the single sided provisioning
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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
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
described in this document, addition of the REVERSE_LSP Object also
allows the initiating node to control the reverse LSP by including
other existing objects in a REVERSE_LSP Object.
Consider again the topology described in Figure 1, where the creation
of reverse LSP2 is triggered by LSP1. Node A signals LSP1 with the
(Extended) ASSOCIATION Object with Association Type indicating single
sided provisioning and inserts a SENDER_TSPEC subobject for use by
LSP2 in the REVERSE_LSP Object in the Path message. Node B then
establishes the LSP2 in the reverse direction using the asymmetric
bandwidth thus specified by LSP1 and allows node A to control the
reverse LSP2.
3.3.2. Double Sided Provisioning
When the double sided provisioning model is used, the two
unidirectional LSPs are established with separate bandwidths, which
may or may not be identical. However, these LSPs are associated
purely based on the identical contents of their (Extended)
ASSOCIATION Objects.
3.4. Recovery LSP Overview
Recovery of each unidirectional LSP forming the bidirectional LSP is
independent [RFC5654] and is based on the parameters signaled in
their respective RSVP Path messages.
Recovery LSP association is based on the identical content of the
(Extended) ASSOCIATION Objects signaled in their Path messages during
the initial LSP setup for both single sided and double sided
provisioning.
4. Message and Object Definitions
4.1. RSVP Message Formats
This section presents the RSVP message-related formats as modified by
this document. Unmodified RSVP message formats are not listed.
The format of a Path message is as follows:
<Path Message> ::= <Common Header> [ <INTEGRITY> ]
[ [<MESSAGE_ID_ACK> | <MESSAGE_ID_NACK>] ... ]
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[ <MESSAGE_ID> ]
<SESSION> <RSVP_HOP>
<TIME_VALUES>
[ <EXPLICIT_ROUTE> ]
<LABEL_REQUEST>
[ <PROTECTION> ]
[ <LABEL_SET> ... ]
[ <SESSION_ATTRIBUTE> ]
[ <NOTIFY_REQUEST> ... ]
[ <ADMIN_STATUS> ]
[ <ASSOCIATION> ... ]
[ <REVERSE_LSP> ... ]
[ <POLICY_DATA> ... ]
<sender descriptor>
The format of the <sender descriptor> is not modified by this
document.
4.2. ASSOCIATION Object
The ASSOCIATION Object is populated using the rules defined below for
associating two reverse unidirectional LSPs to form an associated
bidirectional LSP.
Association Types:
In order to bind two reverse unidirectional LSPs to be an
associated bidirectional LSP, the Association Type MUST be set to
indicate either single sided or double sided LSPs.
The new Association Types are defined as follows (values are
temporary early allocations as per RFC7120):
Value Type
----- -----
3 Double Sided Associated Bidirectional LSP (D)
4 Single Sided Associated Bidirectional LSP (A)
Association ID:
For both single sided and double sided provisioning, Association
ID MUST be set to a value assigned by the node that originates the
association for the bidirectional LSP.
Association Source:
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Association Source MUST be set to an address selected by the node
that originates the association for the bidirectional LSP. For
example, this may be a management entity, or in the case of single
sided provisioning, an address assigned to the node that
originates the LSP.
4.3. Extended ASSOCIATION Object
The Extended ASSOCIATION Object is populated using the rules defined
below for associating two reverse unidirectional LSPs to form a
bidirectional LSP.
The Association Type, Association ID and Association Source MUST be
set as defined for the ASSOCIATION Object in Section 4.1.
Global Association Source:
For both single sided and double sided provisioning, Global
Association Source, when used, MUST be set to the Global_ID
[RFC6370] of the node that originates the association for the
bidirectional LSP.
Extended Association ID:
For both single sided and double sided provisioning, Extended
Association ID, when used, MUST be set to a value selected by the
node that originates the association for the bidirectional LSP.
4.4. REVERSE_LSP Object Definition
4.4.1. REVERSE_LSP Object Format
The information of the reverse LSP is specified via the REVERSE_LSP
Object. This is an optional object carried in a Path message with
Class Number in the form 11bbbbbb and has the following format:
Class_Num = 203 (of the form 11bbbbbb), C_Type = 1 (values are
temporary early allocations as per RFC7120)
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// (Subobjects) //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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4.4.2. REVERSE_LSP Subobjects
The contents of a REVERSE_LSP Object is a variable length series of
subobjects and have the same format as RSVP Objects, see Section
3.1.2 of [RFC2205]. The subobjects permitted in the REVERSE_LSP
Object are previously defined as Path message Objects, and have the
same order in the REVERSE_LSP Object.
Examples of the Path message objects carried in the REVERSE_LSP
Object are (but not limited to):
- SENDER_TSPEC [RFC2205]
- EXPLICIT_ROUTE Object (ERO) [RFC3209]
- SESSION_ATTRIBUTE Object [RFC3209]
- ADMIN_STATUS Object [RFC3473]
- LSP_REQUIRED_ATTRIBUTES Object [RFC5420]
- PROTECTION Object [RFC3473] [RFC4872]
5. Processing Rules
In general, the processing rules for the ASSOCIATION Object are as
specified in [RFC4872] and Extended ASSOCIATION Object are specified
in [RFC6780]. Following sections describe the rules for processing
(Extended) ASSOCIATION and REVERSE_LSP objects for associated
bidirectional LSPs.
5.1. Rules For ASSOCIATION Object
This section defines the processing for the association of two
unidirectional LSPs to form an associated bidirectional LSP. Such
association is based on the use of an (Extended) ASSOCIATION Object.
The procedures related to the actual identification of associations
between LSPs based on (Extended) ASSOCIATION Objects are defined in
[RFC6780]. [RFC6780] specifies that in the absence of Association
Type-specific rule for identifying association, the included
(Extended) ASSOCIATION Objects in the LSPs MUST be identical in order
for an association to exist. This document adds no specific rules
for the new Association Types defined, and the identification of LSP
association therefore proceeds as specified in [RFC6780].
As described in [RFC6780], association of LSPs can be upstream or
downstream initiated, as indicated by (Extended) ASSOCIATION Objects
in Path or Resv Messages. The association of bidirectional LSPs is
always upstream initialized, therefore the Association Types defined
in this document are only to be interpreted in Path Messages. These
types SHOULD NOT be used in ASSOCIATION Objects carried in Resv
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messages and SHOULD be ignored if present.
To indicate an associated bidirectional LSP, an ingress node MUST
insert an (Extended) ASSOCIATION Object into the Path message of the
unidirectional LSP that is part of the associated bidirectional LSP
it initiates. If either Global Association Source or Extended
Association Address is required, then an Extended ASSOCIATION Object
[RFC6780] MUST be inserted in the Path message. Otherwise, an
ASSOCIATION Object MAY be used. Only one (Extended) ASSOCIATION
Object with the Association Types defined in this document SHOULD be
included by an ingress node in an outgoing Path message. (Extended)
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
(Extended) ASSOCIATION Object to "Single Sided Associated
Bidirectional LSP" when single sided provisioning is used, and to
"Double Sided Associated Bidirectional LSP" when double sided
provisioning is used.
A transit node MAY identify the unidirectional LSPs of an associated
bidirectional LSP based on (Extended) ASSOCIATION Objects, with the
Association Type values defined in this document, carried in Path
messages. Clearly, such associations are only possible when the LSPs
transit the node. As mentioned above, such associations are made per
the rules defined in [RFC6780].
Egress nodes which support the Association Types defined in this
document identify the unidirectional LSPs of an associated
bidirectional LSP based on (Extended) ASSOCIATION Objects carried in
Path messages. Note that an ingress node will normally be the
ingress for one of the unidirectional LSPs that make up an associated
bidirectional LSP. When an egress node receives a Path message
containing an (Extended) ASSOCIATION Object with one of the
Association Types defined in this document, it MUST attempt to
identify other LSPs (including ones for which it is an ingress node)
with which the LSP being processed is associated. As defined above,
such associations are made per the rules defined in [RFC6780].
Associated bidirectional LSP teardown follows the standard procedures
defined in [RFC3209] and [RFC3473] either without or with the
administrative status. Generally, the teardown procedures of the
unidirectional LSPs forming an associated bidirectional LSP are
independent of each other, so it is possible that while one LSP
follows graceful teardown with administrative status, the reverse LSP
is torn down without administrative status (using
PathTear/ResvTear/PathErr with state removal). See Section 5.3 below
for additional rules related to LSPs established using single sided
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provisioning.
When an LSP signaled with a Path message containing an (Extended)
ASSOCIATION Object with an Association Type defined in this document
is torn down, the processing node SHALL remove the binding of the LSP
to any previously identified associated bidirectional LSP.
No additional processing is needed for Path messages with an
(Extended) ASSOCIATION Object containing an Association Type field of
Double Sided Associated Bidirectional LSP.
5.1.1. Compatibility For ASSOCIATION Object
The ASSOCIATION Object has been defined in [RFC4872] and the Extended
ASSOCIATION Object has been defined in [RFC6780], both 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.
Operators wishing to use a function supported by a particular
association type SHOULD ensure that the type is supported on any node
that is expected to act on the association [RFC6780].
LSP recovery as defined in [RFC4872] and [RFC4873] is not impacted by
this document. The recovery mechanisms defined in [RFC4872] and
[RFC4873] rely on the use of the (Extended) ASSOCIATION Objects, but
use a different value for Association Type; multiple ASSOCIATION
Objects can be present in the LSP Path message and can coexist with
the procedures defined in this document.
5.2. Rules For REVERSE_LSP Object
A node initiating a Path message containing an ASSOCIATION or
Extended ASSOCIATION Object with the Association Type set to "Single
Sided Associated Bidirectional LSP" MUST include a REVERSE_LSP Object
in the Path message of the LSP when it wishes to control the reverse
LSP originating on the other endpoint node.
The REVERSE_LSP subobject MAY contain any of the specified objects
which the initiating node desires to have included in the Path
message for the associated reverse LSP. A REVERSE_LSP Object MUST
contain at least one subobject. If there is no subobject to be added
in the REVERSE_LSP Object, then the REVERSE_LSP Object MUST NOT be
added in the Path message.
A node receiving a valid Path message containing a REVERSE_LSP Object
that is not the egress node for the LSP being signaled MUST forward
the REVERSE_LSP Object unchanged in the outgoing Path message.
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An egress node, upon receiving a Path message containing an
REVERSE_LSP Object MUST verify that the Path message contains an
ASSOCIATION or Extended ASSOCIATION object with the Association Type
set to "Single Sided Associated Bidirectional LSP". If it does not,
the Path message MUST NOT trigger a reverse LSP. This verification
failure SHOULD NOT trigger any RSVP message but can be logged
locally, and perhaps reported through network management mechanisms.
Once validated, the egress node MUST use the subobjects contained in
any present REVERSE_LSP Objects in the management of the reverse LSP
described in the previous section. Note that the contents of a
REVERSE_LSP Object may change over the life of an LSP and such
changes MUST result in corresponding changes in the reverse LSP. An
egress node MUST tear down and reestablish a new reverse LSP when
REVERSE_LSP Object is either added or removed in the received Path
message.
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" MUST create an LSP in
the reverse direction or reject the Path message by sending a
PathErr.
If REVERSE_LSP Object is not present in the received Path message of
the LSP, the egress node SHOULD use the LSP properties from the
received LSP Path message to signal the LSP in the reverse direction
(which may depend on the local policy). Note that the contents of
the received Path message may change over the life of an LSP and such
changes MUST result in corresponding changes in the reverse LSP. The
teardown of the initiating LSP SHOULD trigger the teardown of the
reverse LSP, however, teardown of the reverse LSP SHOULD NOT trigger
the teardown of the initiating LSP (which may depend on the local
policy).
If REVERSE_LSP Object is present in the received Path message of the
LSP, the egress node follows the procedure defined in Section 5.2 to
setup the reverse LSP. If initiating node controlling the reverse
LSP, wishes to tear down the associated bidirectional LSP, the
initiating node sends a PathTear message to the egress node, the
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egress node MUST trigger to tear down the reverse associated LSP,
however, teardown of the reverse LSP SHOULD NOT trigger the teardown
of the initiating LSP (which may depend on the local policy).
6. IANA Considerations
IANA is requested to administer assignment of new values for
namespace defined in this document and summarized in this section.
6.1. Association Types
IANA maintains the "Generalized Multi-Protocol Label Switching
(GMPLS) Signaling Parameters" registry (see
http://www.iana.org/assignments/gmpls-sig-parameters). "Association
Type" subregistry is included in this registry.
This registry will be updated by new Association Types for
ASSOCIATION and Extended ASSOCIATION Objects defined in this document
as follows:
Value Name Reference
3 Double Sided Associated Bidirectional LSP (D) Section 4.2
4 Single Sided Associated Bidirectional LSP (A) Section 4.2
Specified Association Type values are temporary early allocations as
per RFC7120.
6.2. REVERSE_LSP Object
IANA maintains the "RSVP Parameters" registry (see
http://www.iana.org/assignments/rsvp-parameters/rsvp-parameters.xml).
Class Names, Class Numbers, and Class Types subregistry is included
in this registry.
This registry will be extended for new Class Number (Class-Num) and
Class Type (C-type) for RSVP REVERSE_LSP Object requested in the
11bbbbbb range defined in this document as follows:
Class Number Class Name Reference
203 REVERSE_LSP Section 4.4
- REVERSE_LSP : Class Type or C-type = 1
Specified REVERSE_LSP Class Number and Class Type values are
temporary early allocations as per RFC7120.
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There are no other IANA considerations introduced by this document.
7. Security Considerations
This document introduces two new Association Types, however, no new
security issues relating to the (Extended) ASSOCIATION Object are
introduced.
The procedures defined in this document result in an increased state
information carried in signaling messages. The presence of the
REVERSE_LSP Object necessarily provides more information about the
LSPs. Thus, in the event of the interception of a signaling message,
slightly more information about the state of the network could be
deduced than was previously the case. This is judged to be a very
minor security risk as this information is already available via
routing.
Otherwise, this document introduces no additional security
considerations. For a general discussion on MPLS and GMPLS related
security issues, see the MPLS/GMPLS security framework [RFC5920].
8. Acknowledgement
The authors would like to thank Lou Berger and George Swallow for
their great guidance in this work, Jie Dong for the discussion of
recovery, Lamberto Sterling for his valuable comments on the section
of asymmetric bandwidths, Attila Takacs for the discussion of the
provisioning model and Lou Berger, Daniel King and Deborah Brungard
for the review of the document. At the same time, the authors would
also like to acknowledge the contributions of Bo Wu, Xihua Fu,
Lizhong Jin for the initial discussions, and Wenjuan He for the
prototype implementation. The authors would also like to thank Siva
Sivabalan, Eric Osborne and Robert Sawaya for the discussions on the
ASSOCIATION Object. The authors would like to thank Matt Hartley for
providing useful suggestions on the document and Lou Berger for
careful editorial reviews.
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9. References
9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2205] Braden, B., Zhang, L., Berson, S., Herzog, S., and S.
Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
Functional Specification", RFC 2205, September 1997.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, December 2001.
[RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching
(GMPLS) Signaling Resource ReserVation Protocol-Traffic
Engineering (RSVP-TE) Extensions", RFC 3473, January 2003.
[RFC4872] Lang, J., Rekhter, Y., and D. Papadimitriou, "RSVP-TE
Extensions in Support of End-to-End Generalized Multi-
Protocol Label Switching (GMPLS) Recovery", RFC 4872, May
2007.
[RFC4873] Berger, L., Bryskin, I., Papadimitriou, D., and A. Farrel,
"GMPLS Segment Recovery", RFC 4873, May 2007.
[RFC6780] Berger, L., Le Faucheur, F., and A. Narayanan, "RSVP
Association Object Extensions", RFC 6780, October 2012.
9.2. Informative References
[RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
Element (PCE)-Based Architecture", RFC 4655, August 2006.
[RFC5420] Farrel, A., Ed., Papadimitriou, D., Vasseur, JP., and A.
Ayyangarps, "Encoding of Attributes for MPLS LSP
Establishment Using Resource Reservation Protocol Traffic
Engineering (RSVP-TE)", RFC 5420, February 2009.
[RFC5654] Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N.,
and S. Ueno, "Requirements of an MPLS Transport Profile",
RFC 5654, September 2009.
[RFC5920] Fang, L., "Security Framework for MPLS and GMPLS
Networks", RFC 5920, July 2010.
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[RFC6370] Bocci, M., Swallow, G., and E. Gray, "MPLS Transport
Profile (MPLS-TP) Identifiers", RFC 6370, September 2011.
[RFC6373] Andersson, L., Berger, L., Fang, L., Bitar, N., and E.
Gray, "MPLS Transport Profile (MPLS-TP) Control Plane
Framework", RFC 6373, September 2011.
[RFC6387] Takacs, A., Berger, L., Caviglia, D., Fedyk, D., and J.
Meuric, "GMPLS Asymmetric Bandwidth Bidirectional Label
Switched Paths (LSPs)", RFC 6387, September 2011.
[RFC6689] Berger, L., "Usage of The RSVP Association Object", RFC
6689, July 2012.
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Authors' Addresses
Fei Zhang (editor)
Huawei
Email: zhangfei7@huawei.com
Ruiquan Jing
China Telecom
Email: jingrq@ctbri.com.cn
Rakesh Gandhi (editor)
Cisco Systems
Email: rgandhi@cisco.com
Fan Yang
ZTE
Email: yang.fan240347@gmail.com
Weilian Jiang
ZTE
Email: jiang.weilian@gmail.com
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