MPLS Working Group M. Taillon
Internet-Draft Cisco Systems, Inc.
Updates: 4090 (if approved) T. Saad, Ed.
Intended status: Standards Track Juniper Networks
Expires: July 15, 2020 R. Gandhi
Cisco Systems, Inc.
A. Deshmukh
Juniper Networks
M. Jork
128 Technology
V. Beeram
Juniper Networks
January 12, 2020
RSVP-TE Summary Fast Reroute Extensions for LSP Tunnels
draft-ietf-mpls-summary-frr-rsvpte-08
Abstract
This document updates RFC 4090 for the Resource Reservation Protocol
(RSVP) Traffic-Engineering (TE) procedures defined for facility
backup protection. The updates include extensions that reduce the
amount of signaling and processing that occurs during Fast Reroute
(FRR), and subsequently, improves scalability when undergoing FRR
convergence after a link or node failure. These extensions allow the
RSVP message exchange between the Point of Local Repair (PLR) and the
Merge Point (MP) to be independent of the number of protected Label
Switched Paths (LSPs) traversing between them when facility bypass
FRR protection is used. The signaling extensions are fully backwards
compatible with nodes that do not support them.
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
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 July 15, 2020.
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Copyright Notice
Copyright (c) 2020 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
2. Conventions Used in This Document . . . . . . . . . . . . . . 4
2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2.2. Acronyms and Abbreviations . . . . . . . . . . . . . . . 4
3. Extensions for Summary FRR Signaling . . . . . . . . . . . . 5
3.1. B-SFRR-Ready Extended ASSOCIATION Object . . . . . . . . 6
3.1.1. IPv4 B-SFRR-Ready IPv4 Extended ASSOCIATION ID . . . 7
3.1.2. IPv6 B-SFRR-Ready IPv6 Extended ASSOCIATION ID . . . 8
3.2. B-SFRR-Active Extended ASSOCIATION Object . . . . . . . . 11
3.2.1. IPv4 B-SFRR-Active Extended ASSOCIATION ID . . . . . 12
3.2.2. IPv6 B-SFRR-Active Extended ASSOCIATION ID . . . . . 13
3.3. Signaling Procedures Prior to Failure . . . . . . . . . . 14
3.3.1. PLR Signaling Procedure . . . . . . . . . . . . . . . 15
3.3.2. MP Signaling Procedure . . . . . . . . . . . . . . . 15
3.4. Signaling Procedures Post Failure . . . . . . . . . . . . 16
3.4.1. PLR Signaling Procedure . . . . . . . . . . . . . . . 16
3.4.2. MP Signaling Procedure . . . . . . . . . . . . . . . 17
3.5. Refreshing Summary FRR Active LSPs . . . . . . . . . . . 18
4. Backwards Compatibility . . . . . . . . . . . . . . . . . . . 18
5. Security Considerations . . . . . . . . . . . . . . . . . . . 18
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 19
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 19
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 19
9.1. Normative References . . . . . . . . . . . . . . . . . . 19
9.2. Informative References . . . . . . . . . . . . . . . . . 20
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20
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1. Introduction
The Fast Reroute (FRR) procedures defined in [RFC4090] describe the
mechanisms for the Point of Local Repair (PLR) to reroute traffic and
signaling of a protected RSVP-TE LSP onto the bypass tunnel in the
event of a TE link or node failure. Such signaling procedures are
performed individually for each affected protected LSP. This may
eventually lead to control plane scalability and latency issues on
the PLR and/or the Merge Point (MP) due to limited memory and CPU
processing resources. This condition is exacerbated when the failure
affects a large number of protected LSPs that traverse the same PLR
and MP nodes.
For example, in a large-scale RSVP-TE LSPs deployment, a single LSR
acting as a PLR node may host tens of thousands of protected RSVP-TE
LSPs egressing the same link, and also act as an MP node for a
similar number of LSPs that ingress on the same link. In the event
of the failure of the link or neighbor node, the RSVP-TE control
plane of the node when acting as a PLR becomes busy rerouting
protected LSPs signaling over the bypass tunnel(s) in one direction,
and when acting as an MP node becomes busy merging RSVP states from
signaling received over bypass tunnels for LSP(s) in the reverse
direction. Subsequently, the head-end LER(s) that are notified of
the local repair at downstream LSR will attempt to (re)converge the
affected RSVP-TE LSPs onto newly computed paths - possibly traversing
the same previously affected LSR(s). As a result, the RSVP-TE
control plane at the PLR and MP becomes overwhelmed by the amount of
FRR RSVP-TE processing overhead following the link or node failure,
and due to other control plane protocol(s) (e.g. the IGP) that
undergo convergence on the same node at the same time too.
Today, each protected RSVP-TE LSP is signaled individually over the
bypass tunnel after FRR. The changes introduced in this document
allow the PLR to assign multiple protected LSPs to a bypass tunnel
group and to communicate this assignment to the MP, such that upon
failure, the signaling over the bypass tunnel happens on bypass
tunnel group(s). New extensions are defined in this document to
update the procedures defined in [RFC4090] for facility backup
protection to enable the MP node to become aware of the PLR node's
bypass tunnel assignment group(s) and to allow FRR procedures between
the PLR and the MP nodes to be signaled and processed on per bypass
tunnel group(s).
As defined in [RFC2961], Summary Refresh procedures use MESSAGE_ID to
refresh the RSVP Path and Resv states to help with scaling. The
Summary FRR procedures introduced in this document build on those
concepts to allow the MESSAGE_ID(s) to be exchanged on per bypass
tunnel assignment group, and continue use Summary Refresh procedures
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while reducing the amount of messaging that occurs after rerouting
signaling over the bypass tunnel post FRR.
2. Conventions Used in This Document
2.1. Terminology
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. Acronyms and Abbreviations
The reader is assumed to be familiar with terms and abbreviations
used in [RFC3209] and [RFC4090].
The following abbreviations are also used in this document:
LSR: Label Switching Router
LER: Label Edge Router
MPLS: Multiprotocol Label Switching
LSP: Label Switched Path
MP: Merge Point node as defined in [RFC4090]
PLR: Point of Local Repair node as defined in [RFC4090]
FRR: Fast Reroute as defined in [RFC4090]
B-SFRR-Ready: Bypass Summary FRR Ready Extended ASSOCIATION
object. Added by the PLR for each LSP protected by the bypass
tunnel.
B-SFRR-Active: Bypass Summary FRR Active Extended ASSOCIATION
object. Used to notify the MP node that one or more groups of
protected LSP(s) have been rerouted over the associated bypass
tunnel.
MTU: Maximum transmission unit.
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3. Extensions for Summary FRR Signaling
The RSVP ASSOCIATION object is defined in [RFC4872] as a means to
associate LSPs with each other. For example, in the context of
GMPLS-controlled LSP(s), the object is used to associate recovery
LSPs with the LSP they are protecting. The Extended ASSOCIATION
object is introduced in [RFC6780] to expand on the possible usage of
the ASSOCIATION object and generalize the definition of the Extended
Association ID field.
This document defines the use of the Extended ASSOCIATION object to
carry the Summary FRR information and associate the protected LSP(s)
with the bypass tunnel that protects them. Two new Association Types
for the Extended ASSOCIATION object, and new Extended Association IDs
are proposed in this document to describe the Bypass Summary FRR
Ready (B-SFRR-Ready) and the Bypass Summary FRR Active (B-SFRR-
Active) associations.
The PLR creates and manages the Summary FRR LSP groups (identified by
Bypass_Group_Identifiers) and shares the group identifier(s) with the
MP via signaling.
The PLR SHOULD assign the same Bypass_Group_Identifier to all
protected LSPs that egress the same protected interface and are
protected by the same bypass tunnel. This minimizes the number of
bypass tunnel SFRR groups, and optimizes the amount of signaling
needed between the PLR and the MP after FRR.
The PLR MUST ensure all protected LSP(s) that are assigned the same
Bypass_Group_Identifier use the same modified tunnel sender address
for the backup path identification after FRR as described in
[RFC4090].
The PLR SHOULD assign the same Bypass_Group_Identifier to all
protected LSPs that share the egress link, and bypass tunnel as long
as the protected LSP(s) have the common group attributes, including
the modified tunnel sender address used for backup path
identification as described in [RFC4090].
The MP maintains the PLR group assignments learned via signaling, and
acknowledges the group assignments via signaling. Once the PLR
receives the acknowledgment, FRR signaling can proceed as group
based.
The PLR node that supports Summary FRR procedures adds an Extended
ASSOCIATION object with B-SFRR-Ready Extended Association ID in the
RSVP Path message of the protected LSP. The PLR adds the protected
LSP Bypass_Group_Identifier, information from the assigned bypass
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tunnel, and MESSAGE_ID object into the B-SFRR-Ready Extended
Association ID. The MP uses the information contained in the
received B-SFRR-Ready Extended Association ID to refresh and merge
the protected LSP Path state after FRR occurs.
The MP node that supports Summary FRR procedures adds the B-SFRR-
Ready Extended ASSOCIATION object and respective Extended Association
ID in the RSVP Resv message of the protected LSP to acknowledge the
PLR's bypass tunnel assignment, and provide the MESSAGE_ID object
that the MP node will use to refresh the protected LSP Resv state
after FRR occurs.
This document also defines a new Association Type for the Extended
ASSOCIATION object and new Extended Association ID to describe the B-
SFRR-Active association. The B-SFRR-Active Extended ASSOCIATION
object and Extended Association ID are sent by the PLR after
activating FRR procedures on the PLR. The B-SFRR-Active Extended
ASSOCIATION object and Extended Association ID are sent within the
RSVP Path message of the bypass tunnel to inform the MP node that one
or more groups of protected LSPs protected by the bypass tunnel are
now being rerouted over the bypass tunnel.
3.1. B-SFRR-Ready Extended ASSOCIATION Object
The Extended ASSOCIATION object is populated using the rules defined
below to associate a protected LSP with the bypass tunnel that is
protecting it when Summary FRR procedures are enabled.
The Association Type, Association ID, and Association Source MUST be
set as defined in [RFC4872] for the ASSOCIATION Object. More
specifically:
Association Source:
The Association Source is set to an address of the PLR node.
Association Type:
A new Association Type is defined for B-SFRR-Ready as follows:
Value Type
------- ------
(TBD-1) Bypass Summary FRR Ready Association (B-SFRR-Ready)
Extended ASSOCIATION ID for B-SFRR-Ready:
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The B-SFRR-Ready Extended ASSOCIATION ID is
populated by the PLR for the Bypass Summary FRR Ready association.
The rules to populate the Extended ASSOCIATION ID in this case are
described below.
3.1.1. IPv4 B-SFRR-Ready IPv4 Extended ASSOCIATION ID
The IPv4 Extended ASSOCIATION ID for the B-SFRR-Ready association
type has the following format:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bypass_Tunnel_ID | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bypass_Source_IPv4_Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bypass_Destination_IPv4_Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bypass_Group_Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MESSAGE_ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: The IPv4 Extended ASSOCIATION ID for B-SFRR-Ready
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Bypass_Tunnel_ID: 16 bits
The bypass tunnel identifier.
Reserved: 16 bits
Reserved for future use.
Bypass_Source_IPv4_Address: 32 bits
The bypass tunnel source IPV4 address.
Bypass_Destination_IPv4_Address: 32 bits
The bypass tunnel destination IPV4 address.
Bypass_Group_Identifier: 32 bits
The bypass tunnel group identifier.
MESSAGE_ID
A MESSAGE_ID object as defined by [RFC2961].
3.1.2. IPv6 B-SFRR-Ready IPv6 Extended ASSOCIATION ID
The IPv6 Extended ASSOCIATION ID field for the B-SFRR-Ready
association type has the following format:
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bypass_Tunnel_ID | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Bypass_Source_IPv6_Address +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Bypass_Destination_IPv6_Address +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bypass_Group_Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MESSAGE_ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: The IPv6 Extended ASSOCIATION ID for B-SFRR-Ready
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Bypass_Tunnel_ID: 16 bits
The bypass tunnel identifier.
Reserved: 16 bits
Reserved for future use.
Bypass_Source_IPv6_Address: 128 bits
The bypass tunnel source IPV6 address.
Bypass_Destination_IPv6_Address: 128 bits
The bypass tunnel destination IPV6 address.
Bypass_Group_Identifier: 32 bits
The bypass tunnel group identifier.
MESSAGE_ID
A MESSAGE_ID object as defined by [RFC2961].
The PLR assigns a bypass tunnel and Bypass_Group_Identifier for each
protected LSP. The same Bypass_Group_Identifier is used for the set
of protected LSPs that share the same bypass tunnel, traverse the
same egress link and are not already rerouted. The PLR MUST generate
a MESSAGE_ID object with Epoch and Message_Identifier set according
to [RFC2961]. The MESSAGE_ID object flags SHOULD be cleared when
transmitted by the PLR and ignored when received at the MP.
The PLR MUST generate a new Message_Identifier each time the contents
of the B-SFRR-Ready Extended ASSOCIATION ID changes (e.g. when PLR
node changes the bypass tunnel assignment).
The PLR node notifies the MP node of the bypass tunnel assignment via
adding a B-SFRR-Ready Extended ASSOCIATION object and Extended
Association ID in the RSVP Path message for the protected LSP using
procedures described in Section 3.3.
The MP node acknowledges the assignment to the PLR node by signaling
the B-SFRR-Ready Extended ASSOCIATION object and Extended Association
ID within the RSVP Resv message of the protected LSP. With the
exception of the MESSAGE_ID objects, all other fields of the received
in the B-SFRR-Ready Extended ASSOCIATION ID in the RSVP Path message
are copied into the B-SFRR-Ready Extended ASSOCIATION ID to be added
in the Resv message. The MESSAGE_ID object is set according to
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[RFC2961] with the Flags being clear. A new Message_Identifier MUST
be used to acknowledge an updated PLR assignment.
The PLR considers the protected LSP as Summary FRR capable only if
all the fields in the B-SFRR-Ready Extended ASSOCIATION ID that are
sent in the RSVP Path message match the fields received in the RSVP
Resv message (with exception of the MESSAGE_ID). If the fields do
not match, or if B-SFRR-Ready Extended ASSOCIATION object is absent
in a subsequent refresh, the PLR node MUST consider the protected LSP
as not Summary FRR capable.
3.2. B-SFRR-Active Extended ASSOCIATION Object
The Extended ASSOCIATION object for B-SFRR-Active association type is
populated by a PLR node to indicate to the MP node (bypass tunnel
destination) that one or more groups of Summary FRR protected LSPs
that are being protected by the bypass tunnel are being rerouted over
the bypass tunnel.
The B-SFRR-Active Extended ASSOCIATION object is carried in the RSVP
Path message of the bypass tunnel and signaled downstream towards the
MP (bypass tunnel destination).
The Association Type, Association ID, and Association Source MUST be
set as defined in [RFC4872] for the ASSOCIATION Object. More
specifically:
Association Source:
The Association Source is set to an address of the PLR node.
Association Type:
A new Association Type is defined for B-SFRR-Active as follows:
Value Type
------- ------
(TBD-2) Bypass Summary FRR Active Association (B-SFRR-Active)
Extended ASSOCIATION ID for B-SFRR-Active:
The B-SFRR-Active Extended ASSOCIATION ID is
populated by the PLR for the Bypass Summary FRR Active association.
The rules to populate the Extended ASSOCIATION ID in this case are
described below.
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3.2.1. IPv4 B-SFRR-Active Extended ASSOCIATION ID
The IPv4 Extended ASSOCIATION ID for the B-SFRR-Active association
type is carried inside the IPv4 Extended ASSOCIATION object and has
the following format:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Num-BGIDs | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bypass_Group_Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| : |
// : //
| : |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bypass_Group_Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// RSVP_HOP_Object //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// TIME_VALUES //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 tunnel sender address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: The IPv4 Extended ASSOCIATION ID for B-SFRR-Active
Num-BGIDs: 16 bits
Number of Bypass_Group_Identifier fields.
Reserved: 16 bits
Reserved for future use.
Bypass_Group_Identifier: 32 bits
The Bypass_Group_Identifier that is previously signaled by the PLR
using the Extended Association object. One or more
Bypass_Group_Identifiers MAY be included.
RSVP_HOP_Object: Class 3, as defined by [RFC2205]
Replacement RSVP HOP object to be applied to all LSPs associated
with each of the following Bypass_Group_Identifiers. This
corresponds to C-Type = 1 for IPv4 RSVP HOP.
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TIME_VALUES object: Class 5, as defined by [RFC2205]
Replacement TIME_VALUES object to be applied to all LSPs
associated with each of the following Bypass_Group_Identifiers
after receiving the B-SFRR-Active Extended ASSOCIATION Object.
IPv4 tunnel sender address:
The IPv4 address that the PLR sets to identify backup path(s) as
described in Section 6.1.1 of [RFC4090]. This address is
applicable to all groups identified by Bypass_Group_Identifier(s)
carried in the B-SFRR-Active Extended ASSOCIATION ID.
3.2.2. IPv6 B-SFRR-Active Extended ASSOCIATION ID
The IPv6 Extended ASSOCIATION ID for the B-SFRR-Active association
type is carried inside the IPv6 Extended ASSOCIATION object and has
the following format:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Num-BGIDs | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bypass_Group_Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| : |
// : //
| : |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bypass_Group_Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// RSVP_HOP_Object //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// TIME_VALUES //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ IPv6 tunnel sender address +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: The IPv6 Extended ASSOCIATION ID for B-SFRR-Active
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Num-BGIDs: 16 bits
Number of Bypass_Group_Identifier fields.
Reserved: 16 bits
Reserved for future use.
Bypass_Group_Identifier: 32 bits
The Bypass_Group_Identifier that is previously signaled by the PLR
using the Extended Association object. One or more
Bypass_Group_Identifiers may be included.
RSVP_HOP_Object: Class 3, as defined by [RFC2205]
Replacement RSVP HOP object to be applied to all LSPs associated
with each of the following Bypass_Group_Identifiers. This
corresponds to C-Type = 2 for IPv6 RSVP HOP.
TIME_VALUES object: Class 5, as defined by [RFC2205]
Replacement TIME_VALUES object to be applied to all LSPs
associated with each of the following Bypass_Group_Identifiers
after receiving the B-SFRR-Active Extended ASSOCIATION Object.
IPv6 tunnel sender address:
The IPv6 address that the PLR sets to identify backup path(s) as
described in Section 6.1.1 of [RFC4090]. This address is
applicable to all groups identified by Bypass_Group_Identifier(s)
carried in the B-SFRR-Active Extended ASSOCIATION ID.
3.3. Signaling Procedures Prior to Failure
Before Summary FRR procedures can be used, a handshake MUST be
completed between the PLR and MP. This handshake is performed using
the Extended ASSOCIATION object that carries the B-SFRR-Ready
Extended Association ID in both the RSVP Path and Resv messages of
the protected LSP.
The facility backup method introduced in [RFC4090] takes advantage of
MPLS label stacking (PLR imposing additional MPLS label post FRR) to
allow rerouting of protected traffic over backup path. The backup
path may have stricter MTU requirement and due to label stacking at
PLR, the protected traffic may exceed the backup path MTU. The
operator is assumed to engineer their network to allow rerouting of
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protected traffic and the additional label stacking at PLR to not
exceed the backup path MTU.
When using procedures defined in this document, the PLR MUST ensure
the bypass tunnel assignment can satisfy the protected LSP MTU
requirements post FRR. This avoids any packets from being dropped
due to exceeding the MTU size of the backup path after traffic is
rerouted on to the bypass tunnel post the failure.
3.3.1. PLR Signaling Procedure
The B-SFRR-Ready Extended ASSOCIATION object is added by each PLR in
the RSVP Path message of the protected LSP to record the bypass
tunnel assignment. This object is updated every time the PLR updates
the bypass tunnel assignment and that triggers an RSVP Path change
message.
Upon receiving an RSVP Resv message with B-SFRR-Ready Extended
ASSOCIATION object, the PLR node checks if the expected sub-objects
from the B-SFRR-Ready Extended ASSOCIATION ID are present. If
present, the PLR determines if the MP has acknowledged the current
PLR assignment.
To be a valid acknowledgement, the received B-SFRR-Ready Extended
ASSOCIATION ID contents within the RSVP Resv message of the protected
LSP MUST match the latest B-SFRR-Ready Extended ASSOCIATION object
and Association ID contents that the PLR node had sent within the
RSVP Path message (with exception of the MESSAGE_ID).
Note, when forwarding an RSVP Resv message upstream, the PLR node
SHOULD remove any/all B-SFRR-Ready Extended ASSOCIATION objects whose
Association Source matches the PLR node address.
3.3.2. MP Signaling Procedure
Upon receiving an RSVP Path message with a B-SFRR-Ready Extended
ASSOCIATION object, the MP node processes all (there may be multiple
PLRs for a single MP) B-SFRR-Ready Extended ASSOCIATION objects that
have the MP node address as Bypass Destination address in the
Extended Association ID.
The MP node first ensures the existence of the bypass tunnel and that
the Bypass_Group_Identifier is not already FRR active. That is, an
LSP cannot join a group that is already FRR rerouted.
The MP node builds a mirrored Summary FRR Group database per PLR,
which is determined using the Bypass_Source_Address field. The
MESSAGE_ID is extracted and recorded for the protected LSP Path
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state. The MP node signals a B-SFRR-Ready Extended Association
object and Extended Association ID in the RSVP Resv message of the
protected LSP. With the exception of the MESSAGE_ID objects, all
other fields of the received B-SFRR-Ready Extended ASSOCIATION object
in the RSVP Path message are copied into the B-SFRR-Ready Extended
ASSOCIATION object to be added in the Resv message. The MESSAGE_ID
object is set according to [RFC2961] with the Flags being clear.
Note, an MP may receive more than one RSVP Path message with the B-
SFRR-Ready Extended ASSOCIATION object from different upstream PLR
node(s). In this case, the MP node is expected to save all the
received MESSAGE_IDs from the different upstream PLR node(s). After
a failure, the MP node determines and activates the associated
Summary Refresh ID to use once it receives and processes the RSVP
Path message containing B-SFRR-Active Extended ASSOCIATION object
that is signaled over the bypass tunnel from the PLR, as described
Section 3.4
When forwarding an RSVP Path message downstream, the MP SHOULD remove
any/all B-SFRR-Ready Extended ASSOCIATION object(s) whose Association
ID contains Bypass_Destination_Address matching the MP node address.
3.4. Signaling Procedures Post Failure
Upon detection of the fault (egress link or node failure) the PLR
first performs the object modification procedures described by
Section 6.4.3 of [RFC4090] for all affected protected LSPs. For the
Summary FRR capable LSPs that are assigned to the same bypass tunnel
a common RSVP_HOP and SENDER_TEMPLATE MUST be used.
The PLR MUST signal non-Summary FRR capable LSPs over the bypass
tunnel before signaling the Summary FRR capable LSPs. This is needed
to allow for the case where the PLR node recently changed a bypass
assignment and the MP has not processed the change yet.
The B-SFRR-Active Extended ASSOCIATION object is sent within the RSVP
Path message of the bypass tunnel to reroute RSVP state of Summary
FRR capable LSPs.
3.4.1. PLR Signaling Procedure
After a failure event, when using the Summary FRR path signaling
procedures, an individual RSVP Path message is not signaled for each
Summary FRR LSP. Instead, to reroute Summary FRR LSPs via the bypass
tunnel, the PLR adds the B-SFRR-Active Extended Association object in
the RSVP Path message of the RSVP session of the bypass tunnel.
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The RSVP_HOP_Object field in the B-SFRR-Active Extended ASSOCIATION
ID is set to the common RSVP_HOP that was used by the PLR in
Section 3.3 of this document.
The previously received MESSAGE_ID from the MP is activated. As a
result, the MP may refresh the protected rerouted Resv state using
Summary Refresh procedures.
The PLR adds the Bypass_Group_Identifier(s) of group(s) that have
common group attributes, including the tunnel sender address, to the
same B-SFRR-Active Extended ASSOCIATION ID. Note that multiple
ASSOCIATION objects, each carrying a B-SFRR-Active Extended
ASSOCIATION ID, can be carried within a single RSVP Path message of
the bypass tunnel and sent towards the MP as described in [RFC6780].
3.4.2. MP Signaling Procedure
Upon receiving an RSVP Path message with a B-SFRR-Active Extended
Association object, the MP performs normal merge point processing for
each protected LSP associated with each Bypass_Group_Identifier, as
if it received an individual RSVP Path messages for that LSP.
For each Summary FRR capable LSP that is being merged, the MP first
modifies the Path state as follows:
1. The RSVP_HOP object is copied from the B-SFRR-Active Extended
ASSOCIATION ID.
2. The TIME_VALUES object is copied from the TIMES_VALUE field in
the B-SFRR-Active Extended ASSOCIATION ID. The TIME_VALUES
object contains the refresh time of the PLR to generate refreshes
and that would have exchanged in a Path message sent to the MP
after the failure when no Summary FRR procedures are in effect.
3. The tunnel sender address field in the SENDER_TEMPLATE object is
copied from the tunnel sender address of the B-SFRR-Active
Extended ASSOCIATION ID.
4. The ERO object is modified as per Section 6.4.4 of [RFC4090].
Once the above modifications are completed, the MP node performs
the merge processing as per [RFC4090].
5. The previously received MESSAGE_ID from the PLR is activated,
meaning that the PLR may now refresh the protected rerouted Path
state using Summary Refresh procedures.
A failure during merge processing of any individual rerouted LSP MUST
result in an RSVP Path Error message.
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An individual RSVP Resv message for each successfully merged Summary
FRR LSP is not signaled. The MP node SHOULD immediately use Summary
Refresh procedures to refresh the protected LSP Resv state.
3.5. Refreshing Summary FRR Active LSPs
Refreshing of Summary FRR active LSPs is performed using Summary
Refresh as defined by [RFC2961].
4. Backwards Compatibility
The (Extended) ASSOCIATION object is defined in [RFC4872] with a
class number in the form 11bbbbbb, which ensures compatibility with
non-supporting node(s). Such nodes will ignore the object and
forward it without modification.
5. Security Considerations
This document updates an existing RSVP object. Thus, in the event of
the interception of a signaling message, slightly more information
could be deduced about the state of the network than was previously
the case.
When using procedures defined in this document, FRR (or the reroute
of protected LSP(s) on to the bypass tunnel) can be activated on per
group of protected LSP(s). This allows an intruder to potentially
impact and manipulate a set of protected LSP that are assigned to the
same bypass tunnel group.
Existing mechanisms for maintaining the integrity and authenticity of
RSVP protocol messages [RFC2747] can be applied. Other
considerations mentioned in [RFC4090] and [RFC5920] also apply.
6. IANA Considerations
IANA maintains the "Generalized Multi-Protocol Label Switching
(GMPLS) Signaling Parameters" registry. The "Association Type" sub-
registry is included in this registry.
This registry has been updated by new Association Type for Extended
ASSOCIATION Object defined in this document as follows:
Value Name Reference
----- ---- ---------
TBD-1 B-SFRR-Ready Association Section 3.1
TBD-2 B-SFRR-Active Association Section 3.2
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7. Acknowledgments
The authors would like to thank Alexander Okonnikov, Loa Andersson,
Lou Berger, Eric Osborne, Gregory Mirsky, Mach Chen for reviewing and
providing valuable comments to this document.
8. Contributors
Nicholas Tan
Arista Networks
Email: ntan@arista.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>.
[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>.
[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>.
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[RFC4872] Lang, J., Ed., Rekhter, Y., Ed., and D. Papadimitriou,
Ed., "RSVP-TE Extensions in Support of End-to-End
Generalized Multi-Protocol Label Switching (GMPLS)
Recovery", RFC 4872, DOI 10.17487/RFC4872, May 2007,
<https://www.rfc-editor.org/info/rfc4872>.
[RFC6780] Berger, L., Le Faucheur, F., and A. Narayanan, "RSVP
ASSOCIATION Object Extensions", RFC 6780,
DOI 10.17487/RFC6780, October 2012,
<https://www.rfc-editor.org/info/rfc6780>.
[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>.
9.2. Informative References
[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
Mike Taillon
Cisco Systems, Inc.
Email: mtaillon@cisco.com
Tarek Saad (editor)
Juniper Networks
Email: tsaad@juniper.net
Rakesh Gandhi
Cisco Systems, Inc.
Email: rgandhi@cisco.com
Abhishek Deshmukh
Juniper Networks
Email: adeshmukh@juniper.net
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Markus Jork
128 Technology
Email: mjork@128technology.com
Vishnu Pavan Beeram
Juniper Networks
Email: vbeeram@juniper.net
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