Internet DRAFT - draft-ietf-teas-assoc-corouted-bidir-frr
draft-ietf-teas-assoc-corouted-bidir-frr
TEAS Working Group R. Gandhi, Ed.
Internet-Draft Cisco Systems, Inc.
Updates: 4090, 7551 H. Shah
Intended Status: Standards Track Ciena
Expires: May 8, 2019 J. Whittaker
Verizon
November 4, 2018
Updates to the Fast Reroute Procedures for
Co-routed Associated Bidirectional Label Switched Paths (LSPs)
draft-ietf-teas-assoc-corouted-bidir-frr-07
Abstract
Resource Reservation Protocol (RSVP) association signaling can be
used to bind two unidirectional Label Switched Paths (LSPs) into an
associated bidirectional LSP. When an associated bidirectional LSP
is co-routed, the reverse LSP follows the same path as its forward
LSP. This document updates the Fast Reroute (FRR) procedures defined
in RFC 4090 to support both single-sided and double-sided provisioned
associated bidirectional LSPs. This document also updates the
procedure for associating two reverse LSPs defined in RFC 7551 to
support co-routed bidirectional LSPs. The FRR procedures can ensure
that for the co-routed LSPs, traffic flows on co-routed paths in the
forward and reverse directions after a failure event.
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."
Gandhi, et al. Expires May 8, 2019 [Page 1]
Internet-Draft FRR For Associated Bidirectional LSPs November 4, 2018
Copyright Notice
Copyright (c) 2018 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
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
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Assumptions and Considerations . . . . . . . . . . . . . . 3
2. Conventions Used in This Document . . . . . . . . . . . . . . 4
2.1. Key Word Definitions . . . . . . . . . . . . . . . . . . . 4
2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2.2.1. Forward Unidirectional LSPs . . . . . . . . . . . . . 4
2.2.2. Reverse Co-routed Unidirectional LSPs . . . . . . . . 5
3. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Fast Reroute Bypass Tunnel Assignment . . . . . . . . . . 5
3.2. Node Protection Bypass Tunnels . . . . . . . . . . . . . . 6
3.3. Bidirectional LSP Association At Mid-Points . . . . . . . 7
4. Signaling Procedure . . . . . . . . . . . . . . . . . . . . . 8
4.1. Associated Bidirectional LSP Fast Reroute . . . . . . . . 8
4.1.1. Restoring Co-routing with Node Protection Bypass
Tunnels . . . . . . . . . . . . . . . . . . . . . . . 9
4.1.2. Unidirectional Link Failures . . . . . . . . . . . . . 10
4.1.3. Revertive Behavior after Fast Reroute . . . . . . . . 10
4.1.4. Bypass Tunnel Provisioning . . . . . . . . . . . . . . 10
4.1.5. One-to-One Bypass Tunnel . . . . . . . . . . . . . . . 11
4.2. Bidirectional LSP Association At Mid-points . . . . . . . 11
5. Compatibility . . . . . . . . . . . . . . . . . . . . . . . . 11
6. Security Considerations . . . . . . . . . . . . . . . . . . . 12
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
Appendix A. Extended ASSOCIATION ID . . . . . . . . . . . . . . . 12
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
8.1. Normative References . . . . . . . . . . . . . . . . . . . 14
8.2. Informative References . . . . . . . . . . . . . . . . . . 14
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16
Gandhi, et al. Expires May 8, 2019 [Page 2]
Internet-Draft FRR For Associated Bidirectional LSPs November 4, 2018
1. Introduction
The Resource Reservation Protocol (RSVP) (Extended) ASSOCIATION
Object is specified in [RFC6780] which can be used generically to
associate Multiprotocol Label Switching (MPLS) and Generalized MPLS
(GMPLS) Traffic Engineering (TE) Label Switched Paths (LSPs).
[RFC7551] defines mechanisms for binding two point-to-point
unidirectional LSPs [RFC3209] into an associated bidirectional LSP.
There are two models described in [RFC7551] for provisioning an
associated bidirectional LSP, single-sided and double-sided. In both
models, the reverse LSP of the bidirectional LSP may or may not be
co-routed and follow the same path as its forward LSP.
In some packet transport networks, there are requirements where the
reverse LSP of a bidirectional LSP needs to follow the same path as
its forward LSP [RFC6373]. The MPLS Transport Profile (TP) [RFC6370]
architecture facilitates the co-routed bidirectional LSP by using the
GMPLS extensions [RFC3473] to achieve congruent paths. However, the
RSVP association signaling allows to enable co-routed bidirectional
LSPs without having to deploy GMPLS extensions in the existing
networks. The association signaling also allows to take advantage of
the existing TE and Fast Reroute (FRR) mechanisms in the network.
[RFC4090] defines FRR extensions for MPLS TE LSPs and those are also
applicable to the associated bidirectional LSPs. [RFC8271] defines
FRR procedure for GMPLS signaled bidirectional LSPs, such as,
coordinate bypass tunnel assignments in the forward and reverse
directions of the LSP. The mechanisms defined in [RFC8271] are also
useful for the FRR of associated bidirectional LSPs.
This document updates the FRR procedures defined in [RFC4090] to
support both single-sided and double-sided provisioned associated
bidirectional LSPs. This document also updates the procedure for
associating two reverse LSPs defined in [RFC7551] to support
co-routed bidirectional LSPs. The FRR procedures can ensure that for
the co-routed LSPs, traffic flows on co-routed paths in the forward
and reverse directions after fast reroute.
1.1. Assumptions and Considerations
The following assumptions and considerations apply to this document:
o The FRR procedure for the unidirectional LSPs is defined in
[RFC4090] and is not modified by this document.
o The FRR procedure when using the unidirectional bypass tunnels is
defined in [RFC4090] and is not modified by this document.
Gandhi, et al. Expires May 8, 2019 [Page 3]
Internet-Draft FRR For Associated Bidirectional LSPs November 4, 2018
o This document assumes that the FRR bypass tunnels used for
protected associated bidirectional LSPs are also associated
bidirectional.
o The FRR bypass tunnels used for protected co-routed associated
bidirectional LSPs are assumed to be co-routed associated
bidirectional.
o The FRR procedure to coordinate the bypass tunnel assignment
defined in this document may be used for protected non-corouted
associated bidirectional LSPs but requires that the downstream
Point of Local Repair (PLR) and Merge Point (MP) pair of the
forward LSP matches the upstream MP and PLR pair of the reverse
LSP.
o Unless otherwise specified in this document, the fast reroute
procedures defined in [RFC4090] are used for associated
bidirectional LSPs.
2. Conventions Used in This Document
2.1. Key Word Definitions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2.2. Terminology
The reader is assumed to be familiar with the terminology defined in
[RFC2205], [RFC3209], [RFC4090], [RFC7551], and [RFC8271].
2.2.1. Forward Unidirectional LSPs
Two reverse unidirectional point-to-point (P2P) LSPs are setup in the
opposite directions between a pair of source and destination nodes to
form an associated bidirectional Label Switched Path (LSP). In the
case of single-sided provisioned LSP, the originating LSP with
REVERSE_LSP Object [RFC7551] is identified as a forward
unidirectional LSP. In the case of double-sided provisioned LSP, the
LSP originating from the higher node address (as source) and
terminating on the lower node address (as destination) is identified
as a forward unidirectional LSP.
Gandhi, et al. Expires May 8, 2019 [Page 4]
Internet-Draft FRR For Associated Bidirectional LSPs November 4, 2018
2.2.2. Reverse Co-routed Unidirectional LSPs
Two reverse unidirectional point-to-point (P2P) LSPs are setup in the
opposite directions between a pair of source and destination nodes to
form an associated bidirectional Label Switched Path (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. A reverse co-
routed unidirectional LSP traverses along the same path as the
forward direction unidirectional LSP in the opposite direction.
3. Problem Statement
As specified in [RFC7551], in the single-sided provisioning case, the
RSVP TE tunnel is configured only on one endpoint node of the
bidirectional LSP. An LSP for this tunnel is initiated by the
originating endpoint with (Extended) ASSOCIATION Object containing
Association Type set to "single-sided associated bidirectional LSP"
and REVERSE_LSP Object inserted in the RSVP Path message. The remote
endpoint then creates the corresponding reverse TE tunnel and signals
the reverse LSP in response using the information from the
REVERSE_LSP Object and other objects present in the received RSVP
Path message. As specified in [RFC7551], in the double-sided
provisioning case, the RSVP TE tunnel is configured on both endpoint
nodes of the bidirectional LSP. Both forward and reverse LSPs are
initiated independently by the two endpoints with (Extended)
ASSOCIATION Object containing Association Type set to "double-sided
associated bidirectional LSP". With both single-sided and double-
sided provisioned bidirectional LSPs, the reverse LSP may or may not
be congruent (i.e. co-routed) and follow the same path as its forward
LSP.
Both single-sided and double-sided associated bidirectional LSPs
require solutions to the following issues for fast reroute to ensure
co-routing after a failure event.
3.1. Fast Reroute Bypass Tunnel Assignment
In order to ensure that the traffic flows on a co-routed path after a
link or node failure on the protected co-routed LSP path, the mid-
point Point of Local Repair (PLR) nodes need to assign matching
bidirectional bypass tunnels for fast reroute. Such bypass
assignment requires coordination between the forward and reverse
direction PLR nodes when more than one bypass tunnels are present on
a PLR node.
Gandhi, et al. Expires May 8, 2019 [Page 5]
Internet-Draft FRR For Associated Bidirectional LSPs November 4, 2018
<-- Bypass N -->
+-----+ +-----+
| H +---------+ I |
+--+--+ +--+--+
| |
| |
LSP1 --> | LSP1 --> | LSP1 --> LSP1 -->
+-----+ +--+--+ +--+--+ +-----+ +-----+
| A +--------+ B +----X----+ C +--------+ D +--------+ E |
+-----+ +--+--+ +--+--+ +-----+ +-----+
<-- LSP2 | <-- LSP2 | <-- LSP2 <-- LSP2
| |
| |
+--+--+ +--+--+
| F +---------+ G |
+-----+ +-----+
<-- Bypass S -->
Figure 1: Multiple Bidirectional Bypass Tunnels
As shown in Figure 1, there are two bypass tunnels available, Bypass
tunnel N (on path B-H-I-C) and Bypass tunnel S (on path B-F-G-C).
The mid-point PLR nodes B and C need to coordinate bypass tunnel
assignment to ensure that traffic in both directions flow through
either on the Bypass tunnel N or the Bypass tunnel S, after the link
B-C failure.
3.2. Node Protection Bypass Tunnels
When using a node protection bypass tunnel with a protected
associated bidirectional LSP, after a link failure, the forward and
reverse LSP traffic can flow on different node protection bypass
tunnels in the upstream and downstream directions.
Gandhi, et al. Expires May 8, 2019 [Page 6]
Internet-Draft FRR For Associated Bidirectional LSPs November 4, 2018
<-- Bypass N -->
+-----+ +-----+
| H +------------------------+ I |
+--+--+ +--+--+
| <-- Rerouted-LSP2 |
| |
| |
| LSP1 --> LSP1 --> | LSP1 --> LSP1 -->
+--+--+ +-----+ +--+--+ +-----+ +-----+
| A +--------+ B +----X----+ C +--------+ D +--------+ E |
+-----+ +--+--+ +-----+ +--+--+ +-----+
<-- LSP2 | <-- LSP2 <-- LSP2 | <-- LSP2
| |
| |
| Rerouted-LSP1 --> |
+--+--+ +--+--+
| F +------------------------+ G |
+-----+ +-----+
<-- Bypass S -->
Figure 2: Node Protection Bypass Tunnels
As shown in Figure 2, after the link B-C failure, the downstream PLR
node B reroutes the protected forward LSP1 traffic over the bypass
tunnel S (on path B-F-G-D) to reach downstream MP node D whereas the
upstream PLR node C reroutes the protected reverse LSP2 traffic over
the bypass tunnel N (on path C-I-H-A) to reach the upstream MP node
A. As a result, the traffic in the forward and revere directions
flows on different bypass tunnels and this can cause the co-routed
associated bidirectional LSP to become non-corouted. However, unlike
GMPLS LSPs, the asymmetry of paths in the forward and reverse
directions does not result in RSVP soft-state timeout with the
associated bidirectional LSPs.
3.3. Bidirectional LSP Association At Mid-Points
In packet transport networks, a restoration LSP is signaled after a
link failure on the protected LSP path and the protected LSP may or
may not be torn down [RFC8131]. In this case, multiple forward and
reverse LSPs of a co-routed associated bidirectional LSP may be
present at mid-point nodes with identical (Extended) ASSOCIATION
Objects. This creates an ambiguity at mid-point nodes to identify
the correct associated LSP pair for fast reroute bypass assignment
(e.g. during the recovery phase of RSVP graceful restart procedure).
Gandhi, et al. Expires May 8, 2019 [Page 7]
Internet-Draft FRR For Associated Bidirectional LSPs November 4, 2018
LSP3 --> LSP3 --> LSP3 -->
LSP1 --> LSP1 --> LSP1 --> LSP1 -->
+-----+ +-----+ +-----+ +-----+ +-----+
| A +--------+ B +----X----+ C +--------+ D +--------+ E |
+-----+ +--+--+ +--+--+ +-----+ +-----+
<-- LSP2 | <-- LSP2 | <-- LSP2 <-- LSP2
<-- LSP4 | | <-- LSP4 <-- LSP4
| |
| LSP3 --> |
+--+--+ +--+--+
| F +---------+ G |
+-----+ +-----+
<-- Bypass S -->
<-- LSP4
Figure 3: Restoration LSP Set-up after Link Failure
As shown in Figure 3, the protected LSPs LSP1 and LSP2 are an
associated LSP pair, similarly the restoration LSPs LSP3 and LSP4 are
an associated LSP pair, both pairs belong to the same associated
bidirectional LSP and carry identical (Extended) ASSOCIATION Objects.
In this example, the mid-point node D may mistakenly associate LSP1
with the reverse LSP4 instead of the reverse LSP2 due to the matching
(Extended) ASSOCIATION Objects. This may cause the co-routed
associated bidirectional LSP to become non-corouted after fast
reroute. Since the bypass assignment needs to be coordinated between
the forward and reverse LSPs, this can also lead to undesired bypass
tunnel assignments.
4. Signaling Procedure
4.1. Associated Bidirectional LSP Fast Reroute
For both single-sided and double-sided associated bidirectional LSPs,
the fast reroute procedure specified in [RFC4090] is used. In
addition, the mechanisms defined in [RFC8271] are used as following.
o The BYPASS_ASSIGNMENT IPv4 subobject (value: 38) and IPv6
subobject (value: 39) defined in [RFC8271] are used to coordinate
bypass tunnel assignment between the forward and reverse direction
PLR nodes (see Figure 1). The BYPASS_ASSIGNMENT and Node-ID
address [RFC4561] subobjects MUST be added by the downstream PLR
node in the RECORD_ROUTE Object (RRO) of the RSVP Path message of
the forward LSP to indicate the local bypass tunnel assignment
using the procedure defined in [RFC8271]. The upstream node uses
the bypass assignment information (namely, bypass tunnel source
address, destination address and Tunnel ID) in the received RSVP
Gandhi, et al. Expires May 8, 2019 [Page 8]
Internet-Draft FRR For Associated Bidirectional LSPs November 4, 2018
Path message of the protected forward LSP to find the associated
bypass tunnel in the reverse direction. The upstream PLR node
MUST NOT add the BYPASS_ASSIGNMENT subobject in the RRO of the
RSVP Path message of the reverse LSP.
o The downstream PLR node initiates the bypass tunnel assignment for
the forward LSP. The upstream PLR (forward direction LSP MP) node
reflects the associated bypass tunnel assignment for the reverse
direction LSP. The upstream PLR node MUST NOT initiate the bypass
tunnel assignment.
o If the indicated forward bypass tunnel or the associated reverse
bypass tunnel is not found, the upstream PLR SHOULD send a Notify
message [RFC3473] with Error-code "FRR Bypass Assignment Error"
(value: 44) and Sub-code "Bypass Tunnel Not Found" (value: 1)
[RFC8271] to the downstream PLR.
o If the bypass tunnel can not be used as described in Section 4.5.3
in [RFC8271], the upstream PLR SHOULD send a Notify message
[RFC3473] with Error-code "FRR Bypass Assignment Error" (value:
44) and Sub-code "Bypass Assignment Cannot Be Used" (value: 0)
[RFC8271] to the downstream PLR.
o After a link or node failure, the PLR nodes in both forward and
reverse directions trigger fast reroute independently using the
procedures defined in [RFC4090] and send the forward and protected
reverse LSP modified RSVP Path messages and traffic over the
bypass tunnel. The RSVP Resv signaling of the protected forward
and reverse LSPs follows the same procedure as defined in
[RFC4090] and is not modified by this document.
4.1.1. Restoring Co-routing with Node Protection Bypass Tunnels
After fast reroute, the downstream MP node assumes the role of
upstream PLR and reroutes the reverse LSP RSVP Path messages and
traffic over the bypass tunnel on which the forward LSP RSVP Path
messages and traffic are received. This procedure is defined as
restoring co-routing in [RFC8271]. This procedure is used to ensure
that both forward and reverse LSP signaling and traffic flow on the
same bidirectional bypass tunnel after fast reroute.
As shown in Figure 2, when using a node protection bypass tunnel with
protected co-routed LSPs, asymmetry of paths can occur in the forward
and reverse directions after a link failure [RFC8271]. In order to
restore co-routing, the downstream MP node D (acting as an upstream
PLR) MUST trigger the procedure to restore co-routing and reroute the
protected reverse LSP2 RSVP Path messages and traffic over the bypass
tunnel S (on path D-G-F-B) to the upstream MP node B upon receiving
Gandhi, et al. Expires May 8, 2019 [Page 9]
Internet-Draft FRR For Associated Bidirectional LSPs November 4, 2018
the protected forward LSP modified RSVP Path messages and traffic
over the bypass tunnel S (on path D-G-F-B) from node B. The upstream
PLR node C stops receiving the RSVP Path messages and traffic for the
reverse LSP2 from node D (resulting in RSVP soft-state timeout) and
it stops sending the RSVP Path messages for the reverse LSP2 over the
bypass tunnel N (on path C-I-H-A) to node A.
4.1.2. Unidirectional Link Failures
The unidirectional link failures can cause co-routed associated
bidirectional LSPs to become non-corouted after fast reroute with
both link protection and node protection bypass tunnels. However,
the unidirectional link failures in the upstream and/or downstream
directions do not result in RSVP soft-state timeout with the
associated bidirectional LSPs as upstream and downstream PLRs trigger
fast reroute independently. The asymmetry of forward and reverse LSP
paths due to the unidirectional link failure in the downstream
direction can be corrected by using the procedure to restore co-
routing specified in Section 4.1.1.
4.1.3. Revertive Behavior after Fast Reroute
When the revertive behavior is desired for a protected LSP after the
link is restored, the procedure defined in [RFC4090], Section 6.5.2,
is followed.
o The downstream PLR node starts sending the RSVP Path messages and
traffic flow of the protected forward LSP over the restored link
and stops sending them over the bypass tunnel [RFC4090].
o The upstream PLR node (when the protected LSP is present) also
starts sending the RSVP Path messages and traffic flow of the
protected reverse LSPs over the restored link and stops sending
them over the bypass tunnel [RFC4090].
o In case of node protection bypass tunnels (see Figure 2), after
restoring co-routing, the upstream PLR node D SHOULD start sending
RSVP Path messages and traffic for the reverse LSP over the
original link (C-D) when it receives the un-modified RSVP Path
messages and traffic for the protected forward LSP over it and
stops sending them over the bypass tunnel S (on path D-G-F-B).
4.1.4. Bypass Tunnel Provisioning
Fast reroute bidirectional bypass tunnels can be single-sided or
double-sided associated tunnels. For both single-sided and double-
sided associated bypass tunnels, the fast reroute assignment policies
need to be configured on the downstream PLR nodes of the protected
Gandhi, et al. Expires May 8, 2019 [Page 10]
Internet-Draft FRR For Associated Bidirectional LSPs November 4, 2018
LSPs that initiate the bypass tunnel assignments. For single-sided
associated bypass tunnels, these nodes are the originating endpoints
of their signaling.
4.1.5. One-to-One Bypass Tunnel
The fast reroute signaling procedure defined in this document can be
used for both facility backup described in Section 3.2 of [RFC4090]
and one-to-one backup described in Section 3.1 of [RFC4090]. As
described in Section 5.4.2 of [RFC8271], in one-to-one backup method,
if the associated bidirectional bypass tunnel is already in-use at
the upstream PLR, it SHOULD send a Notify message [RFC3473] with
Error-code "FRR Bypass Assignment Error" (value: 44) and Sub-code
"One-to-One Bypass Already in Use" (value: 2) to the downstream PLR.
4.2. Bidirectional LSP Association At Mid-points
In order to associate the LSPs unambiguously at a mid-point node (see
Figure 3), the endpoint node MUST signal Extended ASSOCIATION Object
and add unique Extended Association ID for each associated forward
and reverse LSP pair forming the bidirectional LSP. An endpoint node
MAY set the Extended Association ID to the value formatted according
to the structure shown in Appendix A.
o For single-sided provisioned bidirectional LSPs [RFC7551], the
originating endpoint signals the Extended ASSOCIATION Object with
a unique Extended Association ID. The remote endpoint copies the
contents of the received Extended ASSOCIATION Object including the
Extended Association ID in the RSVP Path message of the reverse
LSP's Extended ASSOCIATION Object.
o For double-sided provisioned bidirectional LSPs [RFC7551], both
endpoints need to ensure that the bidirectional LSP has a unique
Extended ASSOCIATION Object for each forward and reverse LSP pair
by selecting appropriate unique Extended Association IDs signaled
by them. A controller can be used to provision unique Extended
Association ID on both endpoints. The procedure for selecting
unique Extended Association ID is outside the scope of this
document.
5. Compatibility
This document updates the procedures for fast reroute for associated
bidirectional LSPs defined in [RFC4090] and for associating
bidirectional LSPs defined in [RFC7551]. The procedures use the
signaling messages defined in [RFC8271] and no new signaling messages
are defined in this document. The procedures ensure that for the co-
Gandhi, et al. Expires May 8, 2019 [Page 11]
Internet-Draft FRR For Associated Bidirectional LSPs November 4, 2018
routed LSPs, traffic flows on co-routed paths in the forward and
reverse directions after fast reroute. Operators wishing to use this
function SHOULD ensure that it is supported on all the nodes on the
LSP path. The nodes not supporting this function can cause the
traffic to flow on asymmetric paths in the forward and reverse
directions of the associated bidirectional LSPs after fast reroute.
6. Security Considerations
This document updates the signaling mechanisms defined in [RFC4090]
and [RFC7551]; and does not introduce any additional security
considerations other than those already covered in [RFC4090],
[RFC7551], [RFC8271], and the MPLS/GMPLS security framework
[RFC5920].
7. IANA Considerations
This document does not require any IANA actions.
Appendix A. Extended ASSOCIATION ID
Extended Association ID in the Extended ASSOCIATION Object [RFC6780]
can be set to the value formatted according to the structure shown in
the following example to uniquely identify associated forward and
reverse LSP pair of an associated bidirectional LSP.
An example of IPv4 Extended Association ID format is shown below:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 LSP Source Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | LSP-ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: :
: Variable Length ID :
: :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: IPv4 Extended Association ID Format Example
LSP Source Address
IPv4 source address of the forward LSP [RFC3209].
Gandhi, et al. Expires May 8, 2019 [Page 12]
Internet-Draft FRR For Associated Bidirectional LSPs November 4, 2018
LSP-ID
16-bits LSP-ID of the forward LSP [RFC3209].
Variable Length ID
Variable length ID inserted by the endpoint node of the associated
bidirectional LSP [RFC6780].
An example of IPv6 Extended Association ID format is shown below:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| IPv6 LSP Source Address |
+ +
| (16 bytes) |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | LSP-ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: :
: Variable Length ID :
: :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: IPv6 Extended Association ID Format Example
LSP Source Address
IPv6 source address of the forward LSP [RFC3209].
LSP-ID
16-bits LSP-ID of the forward LSP [RFC3209].
Variable Length ID
Variable length ID inserted by the endpoint node of the associated
bidirectional LSP [RFC6780].
In both IPv4 and IPv6 examples, the Reserved flags MUST be set to 0
on transmission.
Gandhi, et al. Expires May 8, 2019 [Page 13]
Internet-Draft FRR For Associated Bidirectional LSPs November 4, 2018
8. References
8.1. 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.
[RFC4090] Pan, P., Ed., Swallow, G., Ed., and A. Atlas, Ed., "Fast
Reroute Extensions to RSVP-TE for LSP Tunnels", RFC 4090,
May 2005.
[RFC4561] Vasseur, J.P., Ed., Ali, Z., and S. Sivabalan, "Definition
of a Record Route Object (RRO) Node-Id Sub-Object", RFC
4561, June 2006.
[RFC6780] Berger, L., Le Faucheur, F., and A. Narayanan, "RSVP
Association Object Extensions", RFC 6780, October 2012.
[RFC7551] Zhang, F., Ed., Jing, R., and R. Gandhi, Ed., "RSVP-TE
Extensions for Associated Bidirectional Label Switched
Paths (LSPs)", RFC 7551, DOI 10.17487/RFC7551, May 2015,
<https://www.rfc-editor.org/info/rfc7551>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8271] Taillon, M., Saad, T., Ed., Gandhi, R., Ed., Ali, Z., and
M. Bhatia, "Updates to Resource Reservation Protocol for
Fast Reroute of Traffic Engineering GMPLS Label Switched
Paths (LSPs)", RFC 8271, October 2017.
8.2. Informative References
[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.
[RFC5920] Fang, L., "Security Framework for MPLS and GMPLS
Networks", RFC 5920, July 2010.
Gandhi, et al. Expires May 8, 2019 [Page 14]
Internet-Draft FRR For Associated Bidirectional LSPs November 4, 2018
[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.
[RFC8131] Zhang, X., Zheng, H., Ed., Gandhi, R., Ed., Ali, Z., and
P. Brzozowski, "RSVP-TE Signaling Procedure for End-to-End
GMPLS Restoration and Resource Sharing", RFC 8131, March
2017.
Gandhi, et al. Expires May 8, 2019 [Page 15]
Internet-Draft FRR For Associated Bidirectional LSPs November 4, 2018
Acknowledgments
A special thanks to the authors of [RFC8271], this document uses the
signaling mechanisms defined in that document. The authors would
also like to thank Vishnu Pavan Beeram, Daniele Ceccarelli, Deborah
Brungard, Adam Roach and Benjamin Kaduk for reviewing this document
and providing valuable comments.
Authors' Addresses
Rakesh Gandhi (editor)
Cisco Systems, Inc.
Canada
Email: rgandhi@cisco.com
Himanshu Shah
Ciena
Email: hshah@ciena.com
Jeremy Whittaker
Verizon
Email: jeremy.whittaker@verizon.com
Gandhi, et al. Expires May 8, 2019 [Page 16]
