Refresh-interval Independent FRR Facility Protection
draft-ietf-mpls-ri-rsvp-frr-11
| Document | Type | Active Internet-Draft (mpls WG) | |
|---|---|---|---|
| Authors | Chandrasekar R , Tarek Saad , Ina Minei , Dante Pacella | ||
| Last updated | 2021-06-20 | ||
| Replaces | draft-chandra-mpls-ri-rsvp-frr | ||
| Stream | Internet Engineering Task Force (IETF) | ||
| Intended RFC status | Proposed Standard | ||
| Formats | pdf htmlized bibtex | ||
| Reviews | |||
| Stream | WG state | WG Document | |
| Document shepherd | Nicolai Leymann | ||
| Shepherd write-up | Show (last changed 2019-01-18) | ||
| IESG | IESG state | AD is watching | |
| Action Holders |
(None)
|
||
| Consensus Boilerplate | Yes | ||
| Telechat date | |||
| Responsible AD | Martin Vigoureux | ||
| Send notices to | Nicolai Leymann <n.leymann@telekom.de> | ||
| IANA | IANA review state | Version Changed - Review Needed | |
MPLS Working Group C. Ramachandran
Internet-Draft T. Saad
Updates: 4090 (if approved) Juniper Networks, Inc.
Intended status: Standards Track I. Minei
Expires: December 22, 2021 Google, Inc.
D. Pacella
Verizon, Inc.
June 20, 2021
Refresh-interval Independent FRR Facility Protection
draft-ietf-mpls-ri-rsvp-frr-11
Abstract
RSVP-TE Fast ReRoute extensions specified in RFC 4090 defines two
local repair techniques to reroute Label Switched Path (LSP) traffic
over pre-established backup tunnel. Facility backup method allows
one or more LSPs traversing a connected link or node to be protected
using a bypass tunnel. The many-to-one nature of local repair
technique is attractive from scalability point of view. This
document enumerates facility backup procedures in RFC 4090 that rely
on refresh timeout and hence make facility backup method refresh-
interval dependent. The RSVP-TE extensions defined in this document
will enhance the facility backup protection mechanism by making the
corresponding procedures refresh-interval independent and hence
compatible with Refresh-interval Independent RSVP (RI-RSVP) specified
in RFC 8370. Hence, this document updates RFC 4090 in order to
support RI-RSVP capability specified in RFC 8370.
Requirements Language
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 RFC-2119 [RFC2119].
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 https://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
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time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 22, 2021.
Copyright Notice
Copyright (c) 2021 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
(https://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. Motivation . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Problem Description . . . . . . . . . . . . . . . . . . . . . 5
4. Solution Aspects . . . . . . . . . . . . . . . . . . . . . . 7
4.1. Requirement on RFC 4090 Capable Node to advertise RI-RSVP
Capability . . . . . . . . . . . . . . . . . . . . . . . 8
4.2. Signaling Handshake between PLR and MP . . . . . . . . . 9
4.2.1. PLR Behavior . . . . . . . . . . . . . . . . . . . . 9
4.2.2. Remote Signaling Adjacency . . . . . . . . . . . . . 10
4.2.3. MP Behavior . . . . . . . . . . . . . . . . . . . . . 10
4.2.4. "Remote" State on MP . . . . . . . . . . . . . . . . 11
4.3. Impact of Failures on LSP State . . . . . . . . . . . . . 12
4.3.1. Non-MP Behavior . . . . . . . . . . . . . . . . . . . 12
4.3.2. LP-MP Behavior . . . . . . . . . . . . . . . . . . . 13
4.3.3. NP-MP Behavior . . . . . . . . . . . . . . . . . . . 13
4.3.4. Behavior of a Router that is both LP-MP and NP-MP . . 14
4.4. Conditional PathTear . . . . . . . . . . . . . . . . . . 15
4.4.1. Sending Conditional PathTear . . . . . . . . . . . . 15
4.4.2. Processing Conditional PathTear . . . . . . . . . . . 15
4.4.3. CONDITIONS Object . . . . . . . . . . . . . . . . . . 16
4.5. Remote State Teardown . . . . . . . . . . . . . . . . . . 17
4.5.1. PLR Behavior on Local Repair Failure . . . . . . . . 17
4.5.2. PLR Behavior on Resv RRO Change . . . . . . . . . . . 17
4.5.3. LSP Preemption during Local Repair . . . . . . . . . 18
4.5.3.1. Preemption on LP-MP after Phop Link Failure . . . 18
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4.5.3.2. Preemption on NP-MP after Phop Link Failure . . . 18
4.6. Backward Compatibility Procedures . . . . . . . . . . . . 19
4.6.1. Detecting Support for Refresh interval Independent
FRR . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.6.2. Procedures for Backward Compatibility . . . . . . . . 20
4.6.2.1. Lack of support on Downstream Node . . . . . . . 20
4.6.2.2. Lack of support on Upstream Node . . . . . . . . 21
4.6.2.3. Advertising RI-RSVP without RI-RSVP-FRR . . . . . 21
4.6.2.4. Incremental Deployment . . . . . . . . . . . . . 22
5. Security Considerations . . . . . . . . . . . . . . . . . . . 23
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23
6.1. New Object - CONDITIONS . . . . . . . . . . . . . . . . . 23
6.2. CONDITIONS Flags . . . . . . . . . . . . . . . . . . . . 24
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 24
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 24
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 24
9.1. Normative References . . . . . . . . . . . . . . . . . . 24
9.2. Informative References . . . . . . . . . . . . . . . . . 26
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 26
1. Introduction
RSVP-TE relies on periodic refresh of RSVP messages to synchronize
and maintain the Label Switched Path (LSP) related states along the
reserved path. In the absence of refresh messages, the LSP-related
states are automatically deleted. Reliance on periodic refreshes and
refresh timeouts are problematic from the scalability point of view.
The number of RSVP-TE LSPs that a router needs to maintain has been
growing in service provider networks and the implementations should
be capable of handling increase in LSP scale.
RFC 2961 specifies mechanisms to eliminate the reliance on periodic
refresh and refresh timeout of RSVP messages, and enables a router to
increase the message refresh interval to values much longer than the
default 30 seconds defined in RFC 2205. However, the protocol
extensions defined in RFC 4090 for supporting Fast ReRoute (FRR)
using bypass tunnels implicitly rely on short refresh timeouts to
cleanup stale states.
In order to eliminate the reliance on refresh timeouts, the routers
should unambiguously determine when a particular LSP state should be
deleted. In scenarios involving RFC 4090 FRR using bypass tunnels,
additional explicit tear down messages are necessary. Refresh-
interval Independent RSVP FRR (RI-RSVP-FRR) extensions specified in
this document consists of procedures to enable LSP state cleanup that
are essential in supporting RI-RSVP capability for RFC 4090 FRR using
bypass tunnels.
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1.1. Motivation
Base RSVP [RFC2205] maintains state via the generation of RSVP Path/
Resv refresh messages. Refresh messages are used to both synchronize
state between RSVP neighbors and to recover from lost RSVP messages.
The use of Refresh messages to cover many possible failures has
resulted in a number of operational problems.
- One problem relates to RSVP control plane scaling due to periodic
refreshes of Path and Resv messages, another relates to the
reliability and latency of RSVP signaling.
- An additional problem is the time to clean up the stale state
after a tear message is lost. For more on these problems see
Section 1 of RSVP Refresh Overhead Reduction Extensions [RFC2961].
The problems listed above adversely affect RSVP control plane
scalability and RSVP-TE [RFC3209] inherited these problems from
standard RSVP. Procedures specified in [RFC2961] address the above
mentioned problems by eliminating dependency on refreshes for state
synchronization and for recovering from lost RSVP messages, and by
eliminating dependency on refresh timeout for stale state cleanup.
Implementing these procedures allows implementations to improve RSVP-
TE control plane scalability. For more details on eliminating
dependency on refresh timeout for stale state cleanup, refer to
"Refresh-interval Independent RSVP" section 3 of RSVP-TE Scaling
Techniques [RFC8370].
However, the facility backup protection procedures specified in
[RFC4090] do not fully address stale state cleanup as the procedures
depend on refresh timeouts for stale state cleanup. The updated
facility backup protection procedures specified in this document, in
combination with RSVP-TE Scaling Techniques [RFC8370], eliminate this
dependency on refresh timeouts for stale state cleanup.
The procedures specified in this document assume reliable delivery of
RSVP messages, as specified in [RFC2961]. Therefore this document
makes support for [RFC2961] a pre-requisite.
2. Terminology
The reader is expected to be familiar with the terminology in
[RFC2205], [RFC3209], [RFC4090], [RFC4558], [RFC8370] and [RFC8796].
Phop node: Previous-hop router along the label switched path
PPhop node: Previous-Previous-hop router along the label switched
path
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Nhop node: Next-hop router along the label switched path
NNhop node: Next-Next-hop router along the label switched path
PLR: Point of Local Repair router as defined in [RFC4090]
MP: Merge Point router as defined in [RFC4090]
LP-MP node: Merge Point router at the tail of Link-Protecting bypass
tunnel
NP-MP node: Merge Point router at the tail of Node-Protecting bypass
tunnel
TED: Traffic Engineering Database
LSP state: The combination of "path state" maintained as Path State
Block (PSB) and "reservation state" maintained as Reservation State
Block (RSB) forms an individual LSP state on an RSVP-TE speaker
RI-RSVP: The set of procedures defined in Section 3 of RSVP-TE
Scaling Techniques [RFC8370] to eliminate RSVP's reliance on periodic
message refreshes
B-SFRR-Ready: Bypass Summary FRR Ready Extended Association object
defined in Summary FRR extensions [RFC8796] and is added by the PLR
for each protected LSP.
RI-RSVP-FRR: The set of procedures defined in this document to
elimiate RSVP's reliance of periodic message refreshes when
supporting facility backup protection [RFC4090]
Conditional PathTear: A PathTear message containing a suggestion to a
receiving downstream router to retain the path state if the receiving
router is an NP-MP
Remote PathTear: A PathTear message sent from a Point of Local Repair
(PLR) to the MP to delete the LSP state on the MP if PLR had not
previously sent the backup Path state reliably
3. Problem Description
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E
/ \
/ \
/ \
/ \
/ \
/ \
A ----- B ----- C ----- D
\ /
\ /
\ /
\ /
\ /
\ /
F
Figure 1: Example Topology
In the topology in Figure 1, let us consider a large number of LSPs
from A to D transiting B and C. Assume that refresh interval has
been configured to be long of the order of minutes and refresh
reduction extensions are enabled on all routers.
Also let us assume that node protection has been configured for the
LSPs and the LSPs are protected by each router in the following way
- A has made node protection available using bypass LSP A -> E -> C;
A is the PLR and C is the NP-MP
- B has made node protection available using bypass LSP B -> F -> D;
B is the PLR and D is the NP-MP
- C has made link protection available using bypass LSP C -> B -> F
-> D; C is the PLR and D is the LP-MP
In the above condition, assume that B-C link fails. The following is
the sequence of events that is expected to occur for all protected
LSPs under normal conditions.
1. B performs local repair and re-directs LSP traffic over the bypass
LSP B -> F -> D.
2. B also creates backup state for the LSP and triggers sending of
backup LSP state to D over the bypass LSP B -> F -> D.
3. D receives backup LSP states and merges the backups with the
protected LSPs.
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4. As the link on C, over which the LSP states are refreshed, has
failed, C will no longer receive state refreshes. Consequently
the protected LSP states on C will time out and C will send the
tear down messages for all LSPs. As each router should consider
itself as an MP, C will time out the state only after waiting for
an additional duration equal to refresh timeout.
While the above sequence of events has been described in [RFC4090],
there are a few problems for which no mechanism has been specified
explicitly.
- If the protected LSP on C times out before D receives signaling
for the backup LSP, then D would receive a PathTear from C prior
to receiving signaling for the backup LSP, thus resulting in
deleting the LSP state. This would be possible at scale even with
default refresh time.
- If upon the link failure C is to keep state until its timeout,
then with long refresh interval this may result in a large amount
of stale state on C. Alternatively, if upon the link failure C is
to delete the state and send a PathTear to D, this would result in
deleting the state on D, thus deleting the LSP. D needs a
reliable mechanism to determine whether it is an MP or not to
overcome this problem.
- If head-end A attempts to tear down LSP after step 1 but before
step 2 of the above sequence, then B may receive the tear down
message before step 2 and delete the LSP state from its state
database. If B deletes its state without informing D, with long
refresh interval this could cause (large) buildup of stale state
on D.
- If B fails to perform local repair in step 1, then B will delete
the LSP state from its state database without informing D. As B
deletes its state without informing D, with long refresh interval
this could cause (large) buildup of stale state on D.
The purpose of this document is to provide solutions to the above
problems which will then make it practical to scale up to a large
number of protected LSPs in the network.
4. Solution Aspects
The solution consists of five parts.
- Utilize MP determination mechanism specified in RSVP-TE Summary
FRR [RFC8796] that enables the PLR to signal the availability of
local protection to the MP. In addition, introduce PLR and MP
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procedures to to establish Node-ID based hello session between the
PLR and the MP to detect router failures and to determine
capability. See section 4.2 for more details. This part of the
solution re-uses some of the extensions defined in RSVP-TE Summary
FRR [RFC8796] and RSVP-TE Scaling Techniques [RFC8370], and the
subsequent sub-sections will list the extensions in these drafts
that are utilized in this document.
- Handle upstream link or node failures by cleaning up LSP states if
the node has not found itself as an MP through the MP
determination mechanism. See section 4.3 for more details.
- Introduce extensions to enable a router to send a tear down
message to the downstream router that enables the receiving router
to conditionally delete its local LSP state. See section 4.4 for
more details.
- Enhance facility backup protection by allowing a PLR to directly
send a tear down message to the MP without requiring the PLR to
either have a working bypass LSP or have already signaled backup
LSP state. See section 4.5 for more details.
- Introduce extensions to enable the above procedures to be backward
compatible with routers along the LSP path running implementation
that do not support these procedures. See section 4.6 for more
details.
4.1. Requirement on RFC 4090 Capable Node to advertise RI-RSVP
Capability
A node supporting facility backup protection [RFC4090] MUST set the
RI-RSVP capability (I bit) defined in Section 3.1 of RSVP-TE Scaling
Techniques [RFC8370] only if it supports all the extensions specified
in the rest of this document. Hence, this document updates RFC 4090
by defining extensions and additional procedures over facility backup
protection [RFC4090] in order to advertise RI-RSVP capability
[RFC8370]. However, if a node supporting facility backup protection
[RFC4090] does set the RI-RSVP capability (I bit) but does not
support all the extensions specified in the rest of this document,
then it leaves room for stale state to linger around for an
inordinate period of time given the long refresh intervals
recommended by RFC 8370 or disruption of normal FRR operation.
Procedures for backward compatibility Section 4.6.2.3 delves on this
in detail.
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4.2. Signaling Handshake between PLR and MP
4.2.1. PLR Behavior
As per the facility backup procedures [RFC4090], when an LSP becomes
operational on a node and the "local protection desired" flag has
been set in the SESSION_ATTRIBUTE object carried in the Path message
corresponding to the LSP, then the node attempts to make local
protection available for the LSP.
- If the "node protection desired" flag is set, then the node tries
to become a PLR by attempting to create a NP-bypass LSP to the
NNhop node avoiding the Nhop node on protected LSP path. In case
node protection could not be made available, the node attempts to
create an LP-bypass LSP to the Nhop node avoiding only the link
that the protected LSP takes to reach the Nhop
- If the "node protection desired" flag is not set, then the PLR
attempts to create an LP-bypass LSP to the Nhop node avoiding the
link that the protected LSP takes to reach the Nhop
With regard to the PLR procedures described above and that are
specified in RFC 4090, this document specifies the following
additional procedures to support RI-RSVP [RFC8370].
- While selecting the destination address of the bypass LSP, the PLR
MUST select the router ID of the NNhop or Nhop node from the Node-
ID sub-object included in the RRO object carried in the most
recent Resv message corresponding to the LSP. If the MP has not
included a Node-ID sub-object in the Resv RRO and if the PLR and
the MP are in the same area, then the PLR may utilize the TED to
determine the router ID corresponding to the interface address
included by the MP in the RRO object. If the NP-MP in a different
IGP area has not included a Node-ID sub-object in RRO object, then
the PLR MUST execute backward compatibility procedures as if the
downstream nodes along the LSP do not support the extensions
defined in the document (see Section 4.6.2.1).
- The PLR MUST also include its router ID in a Node-ID sub-object in
RRO object carried in any subsequent Path message corresponding to
the LSP. While including its router ID in the Node-ID sub-object
carried in the outgoing Path message, the PLR MUST include the
Node-ID sub-object after including its IPv4/IPv6 address or
unnumbered interface ID sub-object.
- In parallel to the attempt made to create NP-bypass or LP-bypass,
the PLR MUST initiate a Node-ID based Hello session to the NNhop
or Nhop node respectively along the LSP to establish the RSVP-TE
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signaling adjacency. This Hello session is used to detect MP node
failure as well as determine the capability of the MP node. If
the MP has set the I-bit in the CAPABILITY object [RFC8370]
carried in Hello message corresponding to the Node-ID based Hello
session, then the PLR MUST conclude that the MP supports refresh-
interval independent FRR procedures defined in this document. If
the MP has not sent Node-ID based Hello messages or has not set
the I-bit in CAPABILITY object [RFC8370], then the PLR MUST
execute backward compatibility procedures defined in
Section 4.6.2.1 of this document.
- When the PLR associates a bypass to a protected LSP, it MUST
include a B-SFRR-Ready Extended Association object [RFC8796] and
trigger a Path message to be sent for the LSP. If a B-SFRR-Ready
Extended Association object is included in the Path message
corresponding to the LSP, the encoding and object ordering rules
specified in RSVP-TE Summary FRR [RFC8796] MUST be followed. In
addition to those rules, the PLR MUST set the Association Source
in the object to its Node-ID address.
4.2.2. Remote Signaling Adjacency
A Node-ID based RSVP-TE Hello session is one in which Node-ID is used
in the source and the destination address fields of RSVP Hello
messages [RFC4558]. This document extends Node-ID based RSVP Hello
session to track the state of any RSVP-TE neighbor that is not
directly connected by at least one interface. In order to apply
Node-ID based RSVP-TE Hello session between any two routers that are
not immediate neighbors, the router that supports the extensions
defined in the document MUST set TTL to 255 in all outgoing Node-ID
based Hello messages exchanged between the PLR and the MP. The
default hello interval for this Node-ID hello session MUST be set to
the default specified in RSVP-TE Scaling Techniques [RFC8370].
In the rest of the document the term "signaling adjacency", or
"remote signaling adjacency" refers specifically to the RSVP-TE
signaling adjacency.
4.2.3. MP Behavior
With regard to the MP procedures that are defined in [RFC4090] this
document specifies the following additional procedures to support RI-
RSVP defined in [RFC8370].
Each node along an LSP path supporting the extensions defined in this
document MUST also include its router ID in the Node-ID sub-object of
the RRO object carried in the Resv message of the corresponding LSP.
If the PLR has not included a Node-ID sub-object in the RRO object
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carried in the Path message and if the PLR is in a different IGP
area, then the router MUST NOT execute the MP procedures specified in
this document for those LSPs. Instead, the node MUST execute
backward compatibility procedures defined in Section 4.6.2.2 as if
the upstream nodes along the LSP do not support the extensions
defined in this document.
A node receiving a Path message should determine whether the message
contains a B-SFRR-Ready Extended Association object with its own
address as the bypass destination address and whether it has an
operational Node-ID signaling adjacency with the Association source.
If the PLR has not included the B-SFRR-Ready Extended Association
object or if there is no operational Node-ID signaling adjacency with
the PLR identified by the Association source address or if the PLR
has not advertised RI-RSVP capability in its Node-ID based Hello
messages, then the node MUST execute the backward compatibility
procedures defined in Section 4.6.2.2.
If a matching B-SFRR-Ready Extended Association object is found in in
the Path message and if there is an operational remote Node-ID
signaling adjacency with the PLR (identified by the Association
source) that has advertised RI-RSVP capability (I-bit) [RFC8370],
then the node MUST consider itself as the MP for the PLR. The
matching and ordering rules for Bypass Summary FRR Extended
Association specified in RSVP-TE Summary FRR [RFC8796] MUST be
followed by the implementations supporting this document.
- If a matching Bypass Summary FRR Extended Association object is
included by the PPhop node of an LSP and if a corresponding Node-
ID signaling adjacency exists with the PPhop node, then the router
MUST conclude it is the NP-MP.
- If a matching Bypass Summary FRR Extended Association object is
included by the Phop node of an LSP and if a corresponding Node-ID
signaling adjacency exists with the Phop node, then the router
MUST conclude it is the LP-MP.
4.2.4. "Remote" State on MP
Once a router concludes it is the MP for a PLR running refresh-
interval independent FRR procedures as described in the preceding
section, it MUST create a remote path state for the LSP. The only
difference between the "remote" path state and the LSP state is the
RSVP_HOP object. The RSVP_HOP object in a "remote" path state
contains the address that the PLR uses to send Node-ID hello messages
to the MP.
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The MP MUST consider the "remote" path state corresponding to the LSP
automatically deleted if:
- The MP later receives a Path message for the LSP with no matching
B-SFRR-Ready Extended Association object corresponding to the
PLR's IP address contained in the Path RRO, or
- The Node-ID signaling adjacency with the PLR goes down, or
- The MP receives backup LSP signaling for the LSP from the PLR or
- The MP receives a PathTear for the LSP, or
- The MP deletes the LSP state on a local policy or an exception
event
The purpose of "remote" path state is to enable the PLR to explicitly
tear down the path and reservation states corresponding to the LSP by
sending a tear message for the "remote" path state. Such a message
tearing down "remote" path state is called "Remote" PathTear.
The scenarios in which a "Remote" PathTear is applied are described
in Section 4.5.
4.3. Impact of Failures on LSP State
This section describes the procedures that must be executed upon
different kinds of failures by nodes along the path of the LSP. The
procedures that must be executed upon detecting RSVP signaling
adjacency failures do not impact the RSVP-TE graceful restart
mechanisms ([RFC3473], [RFC5063]). If a node executing these
procedures acts as a helper for a neighboring router, then the
signaling adjacency with the neighbor will be declared as having
failed only after taking into account the grace period extended for
the neighbor by this node acting as a helper.
Node failures are detected from the state of Node-ID hello sessions
established with immediate neighbors. RSVP-TE Scaling Techniques
[RFC8370] recommends that each node establish Node-ID hello sessions
with all its immediate neighbors. Non-immediate PLR or MP failure is
detected from the state of remote signaling adjacency established
according to Section 4.2.2 of this document.
4.3.1. Non-MP Behavior
When a router detects the Phop link or the Phop node failure for an
LSP and the router is not an MP for the LSP, then it MUST send a
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Conditional PathTear (refer to Section 4.4 "Conditional PathTear"
below) and delete the PSB and RSB states corresponding to the LSP.
4.3.2. LP-MP Behavior
When the Phop link for an LSP fails on a router that is an LP-MP for
the LSP, the LP-MP MUST retain the PSB and RSB states corresponding
to the LSP till the occurrence of any of the following events.
- The Node-ID signaling adjacency with the Phop PLR goes down, or
- The MP receives a normal or "Remote" PathTear for its PSB, or
- The MP receives a ResvTear for its RSB.
When a router that is an LP-MP for an LSP detects Phop node failure
from the Node-ID signaling adjacency state, the LP-MP MUST send a
normal PathTear and delete the PSB and RSB states corresponding to
the LSP.
4.3.3. NP-MP Behavior
When a router that is an NP-MP for an LSP detects Phop link failure,
or Phop node failure from the Node-ID signaling adjacency, the router
MUST retain the PSB and RSB states corresponding to the LSP till the
occurrence of any of the following events.
- The remote Node-ID signaling adjacency with the PPhop PLR goes
down, or
- The MP receives a normal or "Remote" PathTear for its PSB, or
- The MP receives a ResvTear for its RSB.
When a router that is an NP-MP for an LSP did not detect the Phop
link or the Phop node failure, but receives a Conditional PathTear
from the Phop node, then the router MUST retain the PSB and RSB
states corresponding to the LSP till the occurrence of any of the
following events.
- The remote Node-ID signaling adjacency with the PPhop PLR goes
down, or
- The MP receives a normal or "Remote" PathTear for its PSB, or
- The MP receives a ResvTear for its RSB.
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Receiving a Conditional PathTear from the Phop node will not impact
the "remote" state from the PPhop PLR. Note that the Phop node must
have sent the Conditional PathTear as it was not an MP for the LSP
Section 4.3.1.
In the example topology Figure 1, we assume C & D are the NP-MPs for
the PLRs A & B respectively. Now when A-B link fails, as B is not an
MP and its Phop link has failed, B will delete the LSP state (this
behavior is required for unprotected LSPs - Section 4.3.1). In the
data plane, that would require B to delete the label forwarding entry
corresponding to the LSP. So if B's downstream nodes C and D
continue to retain state, it would not be correct for D to continue
to assume itself as the NP-MP for the PLR B.
The mechanism that enables D to stop considering itself as the NP-MP
for B and delete the corresponding "remote" path state is given
below.
1. When C receives a Conditional PathTear from B, it decides to
retain LSP state as it is the NP-MP of the PLR A. C also MUST
check whether Phop B had previously signaled availability of node
protection. As B had previously signaled NP availability by
including B-SFRR-Ready Extended Association object, C MUST remove
the B-SFRR-Ready Extended Association object containing
Association Source set to B from the Path message and trigger a
Path to D.
2. When D receives the Path message, it realizes that it is no longer
the NP-MP for B and so it deletes the corresponding "remote" path
state. D does not propagate the Path further down because the
only change is that the B-SFRR-Ready Extended Association object
corresponding to Association Source B is no longer present in the
Path message.
4.3.4. Behavior of a Router that is both LP-MP and NP-MP
A router may simultaneously be the LP-MP as well as the NP-MP for the
Phop and the PPhop nodes respectively of an LSP. If the Phop link
fails on such a node, the node MUST retain the PSB and RSB states
corresponding to the LSP till the occurrence of any of the following
events.
- Both Node-ID signaling adjacencies with Phop and PPhop nodes go
down, or
- The MP receives a normal or "Remote" PathTear for its PSB, or
- The MP receives a ResvTear for its RSB.
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If a router that is both an LP-MP and an NP-MP detects Phop node
failure, then the node MUST retain the PSB and RSB states
corresponding to the LSP till the occurrence of any of the following
events.
- The remote Node-ID signaling adjacency with the PPhop PLR goes
down, or
- The MP receives a normal or "Remote" PathTear for its PSB, or
- The MP receives a ResvTear for its RSB.
4.4. Conditional PathTear
In the example provided in the Section 4.3.3, B deletes the PSB and
RSB states corresponding to the LSP once B detects its Phop link went
down as B is not an MP. If B were to send a PathTear normally, then
C would delete LSP state immediately. In order to avoid this, there
should be some mechanism by which B can indicate to C that B does not
require the receiving node to unconditionally delete the LSP state
immediately. For this, B MUST add a new optional CONDITIONS object
in the PathTear. The CONDITIONS object is defined in Section 4.4.3.
If node C also understands the new object, then C MUST NOT delete the
LSP state if it is an NP-MP.
4.4.1. Sending Conditional PathTear
A router that is not an MP for an LSP MUST delete the PSB and RSB
states corresponding to the LSP if the Phop link or the Phop Node-ID
signaling adjacency goes down (Section 4.3.1). The router MUST send
a Conditional PathTear if the following are also true.
- The ingress has requested node protection for the LSP, and
- No PathTear is received from the upstream node
4.4.2. Processing Conditional PathTear
When a router that is not an NP-MP receives a Conditional PathTear,
the node MUST delete the PSB and RSB states corresponding to the LSP,
and process the Conditional PathTear by considering it as a normal
PathTear. Specifically, the node MUST NOT propagate the Conditional
PathTear downstream but remove the optional object and send a normal
PathTear downstream.
When a node that is an NP-MP receives a Conditional PathTear, it MUST
NOT delete LSP state. The node MUST check whether the Phop node had
previously included the B-SFRR-Ready Extended Association object in
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the Path. If the object had been included previously by the Phop,
then the node processing the Conditional PathTear from the Phop MUST
remove the corresponding object and trigger a Path downstream.
If a Conditional PathTear is received from a neighbor that has not
advertised support (refer to Section 4.6) for the new procedures
defined in this document, then the node MUST consider the message as
a normal PathTear. The node MUST propagate the normal PathTear
downstream and delete the LSP state.
4.4.3. CONDITIONS Object
As any implementation that does not support Conditional PathTear MUST
ignore the new object but process the message as a normal PathTear
without generating any error, the Class-Num of the new object MUST be
10bbbbbb where 'b' represents a bit (from Section 3.10 of [RFC2205]).
The new object is called as "CONDITIONS" object that will specify the
conditions under which default processing rules of the RSVP-TE
message MUST be invoked.
The object has the following format:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length | Class | C-type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved |M|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: CONDITIONS Object
Length: This contains the size of the object in bytes and should
be set to eight.
Class: To be assigned
C-type: 1
Merge-point condition (M) bit: If the M bit is set to 1, then the
PathTear message MUST be processed according to the receiver
router role, i.e. if the receiving router is an MP or not for the
LSP.
If the M-bit is set to 0, then the PathTear message MUST be
processed processed as a normal PathTear message for the LSP.
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4.5. Remote State Teardown
If the ingress wants to tear down the LSP because of a management
event while the LSP is being locally repaired at a transit PLR, it
would not be desirable to wait till the completion of backup LSP
signaling to perform state cleanup. To enable LSP state cleanup when
the LSP is being locally repaired, the PLR MUST send a "Remote"
PathTear message instructing the MP to delete the PSB and RSB states
corresponding to the LSP. The TTL in the "Remote" PathTear message
MUST be set to 255.
Let us consider that node C in the example topology (Figure 1) has
gone down and node B locally repairs the LSP.
1. Ingress A receives a management event to tear down the LSP.
2. A sends a normal PathTear for the LSP to B.
3. Assume B has not initiated the backup signaling for the LSP during
local repair. To enable LSP state cleanup, B MUST send a "Remote"
PathTear with destination IP address set to that of the node D
used in the Node-ID signaling adjacency with D, and the RSVP_HOP
object containing local address used in the Node-ID signaling
adjacency.
4. B then deletes the PSB and RSB states corresponding to the LSP.
5. On D there would be a remote signaling adjacency with B and so D
MUST accept the "Remote" PathTear and delete the PSB and RSB
states corresponding to the LSP.
4.5.1. PLR Behavior on Local Repair Failure
If local repair fails on the PLR after a failure, then this MUST be
considered as a case for cleaning up LSP state from the PLR to the
Egress. The PLR achieves state cleanup by sending "Remote" PathTear
to the MP. The MP MUST delete the states corresponding to the LSP
also also propagate the PathTear downstream thereby achieving state
cleanup from all downstream nodes up to the LSP egress. Note that in
the case of link protection, the PathTear MUST be directed to the LP-
MP's Node-ID IP address rather than the Nhop interface address.
4.5.2. PLR Behavior on Resv RRO Change
When a PLR router that has already made NP available for an LSP
detects a change in the RRO carried in the Resv message that
indicates that the router's former NP-MP is no longer present on the
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path of the LSP, then the router MUST send a "Remote" PathTear
directly to its former NP-MP.
In the example topology Figure 1, let us assume A has made node
protection available for an LSP and C has concluded it is the NP-MP
for PLR A. When the B-C link fails then C, implementing the
procedure specified in Section 4.3.4 of this document, will retain
the states corresponding to the LSP until: the remote Node-ID
signaling adjacency with A goes down, or a PathTear or a ResvTear is
received for its PSB or RSB respectively. If B also has made node
protection available, B will eventually complete backup LSP signaling
with its NP-MP D and trigger a Resv to A with RRO changed. The new
RRO of the LSP carried in the Resv will not contain C. When A
processes the Resv message with a new RRO not containing C - its
former NP-MP, A MUST send a "Remote" PathTear to C. When C receives
the "Remote" PathTear for its PSB state, C will send a normal
PathTear downstream to D and delete both the PSB and RSB states
corresponding to the LSP. As D has already received backup LSP
signaling from B, D will retain control plane and forwarding states
corresponding to the LSP.
4.5.3. LSP Preemption during Local Repair
4.5.3.1. Preemption on LP-MP after Phop Link Failure
If an LSP is preempted on an LP-MP after its Phop or the incoming
link has already failed but the backup LSP has not been signaled yet
as part of local repair procedure, then the node MUST send a normal
PathTear and delete both the PSB and RSB states corresponding to the
LSP. As the LP-MP has retained the LSP state expecting the PLR to
initiate backup LSP signaling, preemption would bring down the LSP
and the node would not be LP-MP any more requiring the node to clean
up the LSP state.
4.5.3.2. Preemption on NP-MP after Phop Link Failure
If an LSP is preempted on an NP-MP after its Phop link has already
failed but the backup LSP has not been signaled yet, then the node
MUST send a normal PathTear and delete the PSB and RSB states
corresponding to the LSP. As the NP-MP has retained LSP state
expecting the PLR to initiate backup LSP signaling, preemption would
bring down the LSP and the node would not be NP-MP any more requiring
the node to clean up LSP state.
Let us consider that B-C link goes down on the same example topology
(Figure 1). As C is the NP-MP for the PLR A, C will retain LSP
state.
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1. The LSP is preempted on C.
2. C will delete the RSB state corresponding to the LSP. But C
cannot send a PathErr or a ResvTear to the PLR A because the
backup LSP has not been signaled yet.
3. As the only reason for C having retained state after Phop node
failure was that it was an NP-MP, C MUST send a normal PathTear to
D and delete its PSB state also. D would also delete the PSB and
RSB states on receiving a PathTear from C.
4. B starts backup LSP signaling to D. But as D does not have the
LSP state, it will reject the backup LSP Path and send a PathErr
to B.
5. B will delete its reservation and send a ResvTear to A.
4.6. Backward Compatibility Procedures
"Refresh interval Independent FRR" or RI-RSVP-FRR refers to the set
of procedures defined in this document to elimiate the reliance of
periodic refreshes. The extensions proposed in RSVP-TE Summary FRR
[RFC8796] may apply to implementations that do not support RI-RSVP-
FRR. On the other hand, RI-RSVP-FRR extensions relating to LSP state
cleanup namely Conditional and "Remote" PathTear require support from
one-hop and two-hop neighboring nodes along the LSP path. So
procedures that fall under LSP state cleanup category MUST NOT be
turned on if any of the nodes involved in the node protection FRR
i.e. the PLR, the MP and the intermediate node in the case of NP,
DOES NOT support RI-RSVP-FRR extensions. Note that for LSPs
requesting link protection, only the PLR and the LP-MP MUST support
the extensions.
4.6.1. Detecting Support for Refresh interval Independent FRR
An implementation supporting RI-RSVP-FRR extensions SHOULD set the
flag "Refresh interval Independent RSVP" or RI-RSVP flag in the
CAPABILITY object carried in Hello messages as specified in RSVP-TE
Scaling Techniques [RFC8370]. If an implementation does not set the
flag even if it supports RI-RSVP-FRR extensions, then its neighbors
will view the node as any node that does not support the extensions.
- As nodes supporting the RI-RSVP-FRR extensions initiate Node-ID
based signaling adjacency with all immedate neighbors, such a node
on the path of a protected LSP can determine whether its Phop and
Nhop neighbors support RI-RSVP-FRR enhancements.
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- As nodes supporting the RI-RSVP-FRR extensions also initiate Node-
ID based signaling adjacency with the NNhop along the path of the
LSP requested node protection Section 4.2.1, each node along the
LSP path can determine whether its NNhop node supports RI-RSVP-FRR
enhancements. If the NNhop (a) does not reply to remote Node-ID
Hello messages or (b) does not set the RI-RSVP flag in the
CAPABILITY object carried in its Node-ID Hello messages, then the
node acting as the PLR can conclude that NNhop does not support
RI-RSVP-FRR extensions.
- If node protection is requested for an LSP and if (a) the PPhop
node has not included a matching B-SFRR-Ready Extended Association
object in its Path messages or (b) the PPhop node has not
initiated remote Node-ID Hello messages or (c) the PPhop node does
not set the RI-RSVP flag in the CAPABILITY object carried in its
Node-ID Hello messages, then the node MUST conclude that the PLR
does not support RI-RSVP-FRR extensions.
4.6.2. Procedures for Backward Compatibility
Every node that supports RI-RSVP-FRR MUST support the procedures
defined in this section in order to support backward compatibility
for those subset of LSPs that also traverse nodes that do not support
RI-RSVP-FRR.
4.6.2.1. Lack of support on Downstream Node
The procedures on the downstream direction are as follows.
- If a node finds that the Nhop node along the LSP does not support
the RI-RSVP-FRR extensions, then the node MUST reduce the "refresh
period" in the TIME_VALUES object carried in the Path messages to
the default short refresh interval.
- If node protection is requested for the LSP and the NNhop node
along the LSP path does not support the RI-RSVP-FRR extensions,
then the node MUST reduce the "refresh period" in the TIME_VALUES
object carried in the Path messages to the default short refresh
interval.
If a node reduces the refresh time using the above procedures, it
MUST NOT send any "Remote" PathTear or Conditional PathTear message
to the downstream node.
Consider the example topology in Figure 1. If C does not support the
RI-RSVP-FRR extensions, then:
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- A and B MUST reduce the refresh time to the default short refresh
interval of 30 seconds and trigger a Path message
- If B is not an MP and if Phop link of B fails, B cannot send
Conditional PathTear to C but MUST time out the PSB state from A
normally. Note that B can time out the PSB state A normally only
if A did not set long refresh in the TIME_VALUES object carried in
the Path messages sent earlier.
4.6.2.2. Lack of support on Upstream Node
The procedures are as follows.
- If a node finds that the Phop node along the LSP path does not
support the RI-RSVP-FRR extensions, then the node MUST reduce the
"refresh period" in the TIME_VALUES object carried in the Resv
messages to the default short refresh interval.
- If node protection is requested for the LSP and the Phop node
along the LSP path does not support the RI-RSVP-FRR extensions,
then the the node MUST reduce the "refresh period" in the
TIME_VALUES object carried in the Path messages to the default
short refresh interval (thus, the Nhop can use compatible values
when sending a Resv).
- If node protection is requested for the LSP and the PPhop node
does not support the RI-RSVP-FRR extensions, then the node MUST
reduce the "refresh period" in the TIME_VALUES object carried in
the Resv messages to the default short refresh interval.
- If the node reduces the refresh time using the above procedures,
it MUST NOT execute MP procedures specified in Section 4.3 of this
document.
4.6.2.3. Advertising RI-RSVP without RI-RSVP-FRR
If a node supporting facility backup protection [RFC4090] sets the
RI-RSVP capability (I bit) but does not support the RI-RSVP-FRR
extensions, then it leaves room for stale state to linger around for
an inordinate period of time or disruption of normal FRR operation
(Section 3). Consider the example topology Figure 1 provided in this
document.
- Assume node B does set RI-RSVP capability in its Node-ID based
Hello messages even though it does not support RI-RSVP-FRR
extensions. When B detects the failure of its Phop link along an
LSP, it will not send Conditional PathTear to C as required by the
RI-RSVP-FRR procedures. If B simply leaves the LSP state without
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deleting, then B may end up holding on to the stale state until
the (long) refresh timeout.
- Intead of node B, assume node C does set RI-RSVP capability in its
Node-id based Hello messages even though it does not support RI-
RSVP-FRR extensions. When B details the failure of its Phop link
along an LSP, it will send Conditional PathTear to C as required
by the RI-RSVP-FRR procedures. But, C would not recognize the
condition encoded in the PathTear and end up tearing down the LSP.
- Assume node B does set RI-RSVP capability in its Node-ID based
Hello messages even though it does not support RI-RSVP-FRR
extensions. Also assume local repair is about to commence on node
B for an LSP that has only requested link protection. That is, B
has not initiated the backup LSP signaling for the LSP. If node B
receives a normal PathTear at this time from ingress A because of
a management event initiated on A, then B simply deletes the LSP
state without sending a Remote PathTear to the LP-MP C. So, C may
end up holding on to the stale state until the (long) refresh
timeout.
4.6.2.4. Incremental Deployment
The backward compatibility procedures described in the previous sub-
sections imply that a router supporting the RI-RSVP-FRR extensions
specified in this document can apply the procedures specified in the
document either in the downstream or upstream direction of an LSP,
depending on the capability of the routers downstream or upstream in
the LSP path.
- RI-RSVP-FRR extensions and procedures are enabled for downstream
Path, PathTear and ResvErr messages corresponding to an LSP if
link protection is requested for the LSP and the Nhop node
supports the extensions
- RI-RSVP-FRR extensions and procedures are enabled for downstream
Path, PathTear and ResvErr messages corresponding to an LSP if
node protection is requested for the LSP and both Nhop & NNhop
nodes support the extensions
- RI-RSVP-FRR extensions and procedures are enabled for upstream
PathErr, Resv and ResvTear messages corresponding to an LSP if
link protection is requested for the LSP and the Phop node
supports the extensions
- RI-RSVP-FRR extensions and procedures are enabled for upstream
PathErr, Resv and ResvTear messages corresponding to an LSP if
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node protection is requested for the LSP and both Phop and the
PPhop support the extensions
For example, if an implementation supporting the RI-RSVP-FRR
extensions specified in this document is deployed on all routers in
particular region of the network and if all the LSPs in the network
request node protection, then the FRR extensions will only be applied
for the LSP segments that traverse the particular region. This will
aid incremental deployment of these extensions and also allow reaping
the benefits of the extensions in portions of the network where it is
supported.
5. Security Considerations
The security considerations pertaining to [RFC2961], [RFC4090],
[RFC8370], [RFC8796] and [RFC5920] remain relevant. When using RSVP
Cryptographic Authentication [RFC2747], more robust algorithms
[RFC2104] [FIPS-180-3] SHOULD be used when computing the keyed
message digest where possible.
This document extends the applicability of Node-ID based Hello
session between immediate neighbors. The Node-ID based Hello session
between the PLR and the NP-MP may require the two routers to exchange
Hello messages with non-immediate neighbor. So, the implementations
SHOULD provide the option to configure Node-ID neighbor specific or
global authentication key to authentication messages received from
Node-ID neighbors. The network administrator SHOULD utilize this
option to enable RSVP-TE routers to authenticate Node-ID Hello
messages received with TTL greater than 1. Implementations SHOULD
also provide the option to specify a limit on the number of Node-ID
based Hello sessions that can be established on a router supporting
the extensions defined in this document.
6. IANA Considerations
6.1. New Object - CONDITIONS
RSVP Change Guidelines [RFC3936] defines the Class-Number name space
for RSVP objects. The name space is managed by IANA.
IANA registry: RSVP Parameters
Subsection: Class Names, Class Numbers, and Class Types
A new RSVP object using a Class-Number from 128-183 range called the
"CONDITIONS" object is defined in Section 4.4 of this document. The
Class-Number from 128-183 range will be allocated by IANA.
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6.2. CONDITIONS Flags
Apart from allocating Class-Number for the CONDITIONS object, the
allocation of the Merge-point condition bit or M-bit Section 4.4 will
also be done by IANA.
Flag: 0x1 Name: Merge-point condition bit or M-bit
7. Acknowledgements
We are very grateful to Yakov Rekhter for his contributions to the
development of the idea and thorough review of content of the draft.
We are thankful to Raveendra Torvi and Yimin Shen for their comments
and inputs on early versions of the draft. We also thank Alexander
Okonnikov for his review and comments on the draft.
8. Contributors
Markus Jork
Juniper Networks, Inc.
Email: mjork@juniper.net
Harish Sitaraman
Individual Contributor
Email: harish.ietf@gmail.com
Vishnu Pavan Beeram
Juniper Networks, Inc.
Email: vbeeram@juniper.net
Ebben Aries
Arrcus, Inc.
Email: exa@arrcus.com
Mike Taillon
Cisco Systems, Inc.
Email: mtaillon@cisco.com
9. References
9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
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[RFC2205] Braden, R., Ed., Zhang, L., Berson, S., Herzog, S., and S.
Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
Functional Specification", RFC 2205, DOI 10.17487/RFC2205,
September 1997, <https://www.rfc-editor.org/info/rfc2205>.
[RFC2747] Baker, F., Lindell, B., and M. Talwar, "RSVP Cryptographic
Authentication", RFC 2747, DOI 10.17487/RFC2747, January
2000, <https://www.rfc-editor.org/info/rfc2747>.
[RFC2961] Berger, L., Gan, D., Swallow, G., Pan, P., Tommasi, F.,
and S. Molendini, "RSVP Refresh Overhead Reduction
Extensions", RFC 2961, DOI 10.17487/RFC2961, April 2001,
<https://www.rfc-editor.org/info/rfc2961>.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001,
<https://www.rfc-editor.org/info/rfc3209>.
[RFC3473] Berger, L., Ed., "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Resource ReserVation Protocol-
Traffic Engineering (RSVP-TE) Extensions", RFC 3473,
DOI 10.17487/RFC3473, January 2003,
<https://www.rfc-editor.org/info/rfc3473>.
[RFC3936] Kompella, K. and J. Lang, "Procedures for Modifying the
Resource reSerVation Protocol (RSVP)", BCP 96, RFC 3936,
DOI 10.17487/RFC3936, October 2004,
<https://www.rfc-editor.org/info/rfc3936>.
[RFC4090] Pan, P., Ed., Swallow, G., Ed., and A. Atlas, Ed., "Fast
Reroute Extensions to RSVP-TE for LSP Tunnels", RFC 4090,
DOI 10.17487/RFC4090, May 2005,
<https://www.rfc-editor.org/info/rfc4090>.
[RFC4558] Ali, Z., Rahman, R., Prairie, D., and D. Papadimitriou,
"Node-ID Based Resource Reservation Protocol (RSVP) Hello:
A Clarification Statement", RFC 4558,
DOI 10.17487/RFC4558, June 2006,
<https://www.rfc-editor.org/info/rfc4558>.
[RFC5063] Satyanarayana, A., Ed. and R. Rahman, Ed., "Extensions to
GMPLS Resource Reservation Protocol (RSVP) Graceful
Restart", RFC 5063, DOI 10.17487/RFC5063, October 2007,
<https://www.rfc-editor.org/info/rfc5063>.
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[RFC8370] Beeram, V., Ed., Minei, I., Shakir, R., Pacella, D., and
T. Saad, "Techniques to Improve the Scalability of RSVP-TE
Deployments", RFC 8370, DOI 10.17487/RFC8370, May 2018,
<https://www.rfc-editor.org/info/rfc8370>.
[RFC8796] Taillon, M., Saad, T., Ed., Gandhi, R., Deshmukh, A.,
Jork, M., and V. Beeram, "RSVP-TE Summary Fast Reroute
Extensions for Label Switched Path (LSP) Tunnels",
RFC 8796, DOI 10.17487/RFC8796, July 2020,
<https://www.rfc-editor.org/info/rfc8796>.
9.2. Informative References
[FIPS-180-3]
National Institute of Standards and Technology, "Secure
Hash Standard", FIPS 180-3, October 2008.
[RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed-
Hashing for Message Authentication", RFC 2104,
DOI 10.17487/RFC2104, February 1997,
<https://www.rfc-editor.org/info/rfc2104>.
[RFC5920] Fang, L., Ed., "Security Framework for MPLS and GMPLS
Networks", RFC 5920, DOI 10.17487/RFC5920, July 2010,
<https://www.rfc-editor.org/info/rfc5920>.
Authors' Addresses
Chandra Ramachandran
Juniper Networks, Inc.
Email: csekar@juniper.net
Tarek Saad
Juniper Networks, Inc.
Email: tsaad@juniper.net
Ina Minei
Google, Inc.
Email: inaminei@google.com
Ramachandran, et al. Expires December 22, 2021 [Page 26]
Internet-Draft RI-RSVP FRR Bypass June 2021
Dante Pacella
Verizon, Inc.
Email: dante.j.pacella@verizon.com
Ramachandran, et al. Expires December 22, 2021 [Page 27]