draft-ietf-teas-rsvp-ingress-protection-03.txt   draft-ietf-teas-rsvp-ingress-protection-04.txt 
Internet Engineering Task Force H. Chen, Ed. Internet Engineering Task Force H. Chen, Ed.
Internet-Draft Huawei Technologies Internet-Draft Huawei Technologies
Intended status: Standards Track R. Torvi, Ed. Intended status: Standards Track R. Torvi, Ed.
Expires: December 22, 2015 Juniper Networks Expires: April 21, 2016 Juniper Networks
June 20, 2015 October 19, 2015
Extensions to RSVP-TE for LSP Ingress Local Protection Extensions to RSVP-TE for LSP Ingress Local Protection
draft-ietf-teas-rsvp-ingress-protection-03.txt draft-ietf-teas-rsvp-ingress-protection-04.txt
Abstract Abstract
This document describes extensions to Resource Reservation Protocol - This document describes extensions to Resource Reservation Protocol -
Traffic Engineering (RSVP-TE) for locally protecting the ingress node Traffic Engineering (RSVP-TE) for locally protecting the ingress node
of a Traffic Engineered (TE) Label Switched Path (LSP), which is a of a Traffic Engineered (TE) Label Switched Path (LSP), which is a
Point-to-Point (P2P) LSP or a Point-to-Multipoint (P2MP) LSP. Point-to-Point (P2P) LSP or a Point-to-Multipoint (P2MP) LSP.
Status of this Memo Status of this Memo
skipping to change at page 1, line 34 skipping to change at page 1, line 34
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 22, 2015. This Internet-Draft will expire on April 21, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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3.2. Backup and Source Detect Failure . . . . . . . . . . . . . 5 3.2. Backup and Source Detect Failure . . . . . . . . . . . . . 5
4. Backup Forwarding State . . . . . . . . . . . . . . . . . . . 5 4. Backup Forwarding State . . . . . . . . . . . . . . . . . . . 5
4.1. Forwarding State for Backup LSP . . . . . . . . . . . . . 5 4.1. Forwarding State for Backup LSP . . . . . . . . . . . . . 5
5. Protocol Extensions . . . . . . . . . . . . . . . . . . . . . 6 5. Protocol Extensions . . . . . . . . . . . . . . . . . . . . . 6
5.1. INGRESS_PROTECTION Object . . . . . . . . . . . . . . . . 6 5.1. INGRESS_PROTECTION Object . . . . . . . . . . . . . . . . 6
5.1.1. Subobject: Backup Ingress IPv4 Address . . . . . . . . 7 5.1.1. Subobject: Backup Ingress IPv4 Address . . . . . . . . 7
5.1.2. Subobject: Backup Ingress IPv6 Address . . . . . . . . 8 5.1.2. Subobject: Backup Ingress IPv6 Address . . . . . . . . 8
5.1.3. Subobject: Ingress IPv4 Address . . . . . . . . . . . 8 5.1.3. Subobject: Ingress IPv4 Address . . . . . . . . . . . 8
5.1.4. Subobject: Ingress IPv6 Address . . . . . . . . . . . 8 5.1.4. Subobject: Ingress IPv6 Address . . . . . . . . . . . 8
5.1.5. Subobject: Traffic Descriptor . . . . . . . . . . . . 9 5.1.5. Subobject: Traffic Descriptor . . . . . . . . . . . . 9
5.1.6. Subobject: Label-Routes . . . . . . . . . . . . . . . 10 5.1.6. Subobject: Label-Routes . . . . . . . . . . . . . . . 9
6. Behavior of Ingress Protection . . . . . . . . . . . . . . . . 10 6. Behavior of Ingress Protection . . . . . . . . . . . . . . . . 10
6.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . 10 6.1. Ingress Behavior . . . . . . . . . . . . . . . . . . . . . 10
6.1.1. Relay-Message Method . . . . . . . . . . . . . . . . . 10 6.2. Backup Ingress Behavior . . . . . . . . . . . . . . . . . 11
6.1.2. Proxy-Ingress Method . . . . . . . . . . . . . . . . . 11 6.2.1. Backup Ingress Behavior in Off-path Case . . . . . . . 11
6.1.3. Comparing Two Methods . . . . . . . . . . . . . . . . 12 6.2.2. Backup Ingress Behavior in On-path Case . . . . . . . 13
6.2. Ingress Behavior . . . . . . . . . . . . . . . . . . . . . 12 6.2.3. Failure Detection and Refresh PATH Messages . . . . . 14
6.2.1. Relay-Message Method . . . . . . . . . . . . . . . . . 13 6.3. Revertive Behavior . . . . . . . . . . . . . . . . . . . . 14
6.2.2. Proxy-Ingress Method . . . . . . . . . . . . . . . . . 13 6.3.1. Revert to Primary Ingress . . . . . . . . . . . . . . 15
6.3. Backup Ingress Behavior . . . . . . . . . . . . . . . . . 14 6.3.2. Global Repair by Backup Ingress . . . . . . . . . . . 15
6.3.1. Backup Ingress Behavior in Off-path Case . . . . . . . 15 7. Security Considerations . . . . . . . . . . . . . . . . . . . 15
6.3.2. Backup Ingress Behavior in On-path Case . . . . . . . 17 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
6.3.3. Failure Detection and Refresh PATH Messages . . . . . 18 8.1. A New Class Number . . . . . . . . . . . . . . . . . . . . 16
6.4. Revertive Behavior . . . . . . . . . . . . . . . . . . . . 18 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 16
6.4.1. Revert to Primary Ingress . . . . . . . . . . . . . . 18 10. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 17
6.4.2. Global Repair by Backup Ingress . . . . . . . . . . . 19 11. Normative References . . . . . . . . . . . . . . . . . . . . . 17
7. Security Considerations . . . . . . . . . . . . . . . . . . . 19 A. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 18
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19
8.1. A New Class Number . . . . . . . . . . . . . . . . . . . . 19
9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 20
10. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 21
11. Normative References . . . . . . . . . . . . . . . . . . . . . 21
A. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 22
1. Co-authors 1. Co-authors
Ning So, Autumn Liu, Alia Atlas, Yimin Shen, Tarek Saad, Fengman Xu, Ning So, Autumn Liu, Alia Atlas, Yimin Shen, Tarek Saad, Fengman Xu,
Mehmet Toy, Lei Liu Mehmet Toy, Lei Liu
2. Introduction 2. Introduction
For a MPLS LSP it is important to have a fast-reroute method for For a MPLS LSP it is important to have a fast-reroute method for
protecting its ingress node and transit nodes. Protecting an ingress protecting its ingress node and transit nodes. Protecting an ingress
skipping to change at page 6, line 32 skipping to change at page 6, line 32
object into the PATH message to be sent to the backup ingress for object into the PATH message to be sent to the backup ingress for
protecting the primary ingress. It has the following format: protecting the primary ingress. It has the following format:
Class-Num = TBD C-Type = 1 for INGRESS_PROTECTION_IPv4 Class-Num = TBD C-Type = 1 for INGRESS_PROTECTION_IPv4
C-Type = 2 for INGRESS_PROTECTION_IPv6 C-Type = 2 for INGRESS_PROTECTION_IPv6
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length (bytes) | Class-Num | C-Type | | Length (bytes) | Class-Num | C-Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Secondary LSP ID | Flags | Options | | Reserved (zero) | Flags | Options |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ (Subobjects) ~ ~ (Subobjects) ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Flags Flags
0x01 Ingress local protection available 0x01 Ingress local protection available
0x02 Ingress local protection in use 0x02 Ingress local protection in use
0x04 Bandwidth protection 0x04 Bandwidth protection
Options Options
0x01 Revert to Ingress 0x01 Revert to Ingress
0x02 P2MP Backup 0x02 P2MP Backup
The Secondary LSP ID in the object is an LSP ID that the primary
ingress has allocated for a protected LSP tunnel. The backup ingress
may use this LSP ID to set up a new LSP from the backup ingress to
the destinations of the protected LSP tunnel. This allows the new
LSP to share resources with the old one.
The flags are used to communicate status information from the backup The flags are used to communicate status information from the backup
ingress to the primary ingress. ingress to the primary ingress.
o Ingress local protection available: The backup ingress sets this o Ingress local protection available: The backup ingress sets this
flag after backup LSPs are up and ready for locally protecting the flag after backup LSPs are up and ready for locally protecting the
primary ingress. The backup ingress sends this to the primary primary ingress. The backup ingress sends this to the primary
ingress to indicate that the primary ingress is locally protected. ingress to indicate that the primary ingress is locally protected.
o Ingress local protection in use: The backup ingress sets this flag o Ingress local protection in use: The backup ingress sets this flag
when it detects a failure in the primary ingress. The backup when it detects a failure in the primary ingress. The backup
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~ Subobjects ~ ~ Subobjects ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Subobjects in the Label-Routes are copied from those in the The Subobjects in the Label-Routes are copied from those in the
RECORD_ROUTE objects in the RESV messages that the primary ingress RECORD_ROUTE objects in the RESV messages that the primary ingress
receives from its next hops for the primary LSP. They MUST contain receives from its next hops for the primary LSP. They MUST contain
the first hops of the LSP, each of which is paired with its label. the first hops of the LSP, each of which is paired with its label.
6. Behavior of Ingress Protection 6. Behavior of Ingress Protection
6.1. Overview
There are four parts of ingress protection: 1) setting up the There are four parts of ingress protection: 1) setting up the
necessary backup LSP forwarding state; 2) identifying the failure and necessary backup LSP forwarding state; 2) identifying the failure and
providing the fast repair (as discussed in Sections 3 and 4); 3) providing the fast repair (as discussed in Sections 3 and 4); 3)
maintaining the RSVP-TE control plane state until a global repair is maintaining the RSVP-TE control plane state until a global repair is
done; and 4) performing the global repair(see Section 6.4). done; and 4) performing the global repair(see Section 6.3).
There are two different proposed signaling approaches to obtain
ingress protection. They both use the same new INGRESS_PROTECTION
object. The object is sent in both PATH and RESV messages.
6.1.1. Relay-Message Method
The primary ingress relays the information for ingress protection of
an LSP to the backup ingress via PATH messages. Once the LSP is
created, the ingress of the LSP sends the backup ingress a PATH
message with an INGRESS_PROTECTION object with Label-Routes
subobject, which is populated with the next-hops and labels. This
provides sufficient information for the backup ingress to create the
appropriate forwarding state and backup LSP(s).
The ingress also sends the backup ingress all the other PATH messages
for the LSP with an empty INGRESS_PROTECTION object. Thus, the
backup ingress has access to all the PATH messages needed for
modification to refresh control-plane state after a failure.
The advantages of this method include: 1) the primary LSP is
independent of the backup ingress; 2) simple; 3) less configuration;
and 4) less control traffic.
6.1.2. Proxy-Ingress Method
Conceptually, a proxy ingress is created that starts the RSVP
signaling. The explicit path of the LSP goes from the proxy ingress
to the backup ingress and then to the real ingress. The behavior and
signaling for the proxy ingress is done by the real ingress; the use
of a proxy ingress address avoids problems with loop detection.
[ traffic source ] *** Primary LSP
$ $ --- Backup LSP
$ $ $$ Link
$ $
[ proxy ingress ] [ backup ]
[ & ingress ] |
* |
*****[ MP ]----|
Figure 2: Example Protected LSP with Proxy Ingress Node
The backup ingress must know the merge points or next-hops and their
associated labels. This is accomplished by having the RSVP PATH and
RESV messages go through the backup ingress, although the forwarding
path need not go through the backup ingress. If the backup ingress
fails, the ingress simply removes the INGRESS_PROTECTION object and
forwards the PATH messages to the LSP's next-hop(s). If the ingress
has its LSP configured for ingress protection, then the ingress can
add the backup ingress and itself to the ERO and start forwarding the
PATH messages to the backup ingress.
Slightly different behavior can apply for the on-path and off-path
cases. In the on-path case, the backup ingress is a next hop node
after the ingress for the LSP. In the off-path, the backup ingress
is not any next-hop node after the ingress for all associated sub-
LSPs.
The key advantage of this approach is that it minimizes the special
handling code requires. Because the backup ingress is on the
signaling path, it can receive various notifications. It easily has
access to all the PATH messages needed for modification to be sent to
refresh control-plane state after a failure.
6.1.3. Comparing Two Methods
+-------+-----------+-------+--------------+---------------+---------+
|\_ Item|Primary LSP|Config |PATH Msg from |RESV Msg from |Reuse |
| \_ |Depends on |Proxy- |Backup Ingress|Primary Ingress|Some |
| \|Backup |Ingress|to Primary |to Backup |Existing |
|Method |Ingress |ID |Ingress |Ingress |Functions|
+-------+-----------+-------+--------------+---------------+---------+
|Relay- | No | No | No | No | Yes- |
|Message| | | | | |
+-------+-----------+-------+--------------+---------------+---------+
|Proxy- | Yes | Yes- | Yes | Yes | Yes |
|Ingress| | | | | |
+-------+-----------+-------+--------------+---------------+---------+
6.2. Ingress Behavior 6.1. Ingress Behavior
The primary ingress MUST be configured with a couple of pieces of The primary ingress MUST be configured with a couple of pieces of
information for ingress protection. information for ingress protection.
o Backup Ingress Address: The primary ingress MUST know an IP o Backup Ingress Address: The primary ingress MUST know an IP
address for it to be included in the INGRESS_PROTECTION object. address for it to be included in the INGRESS_PROTECTION object.
o Proxy-Ingress-Id (only needed for Proxy-Ingress Method): The
Proxy-Ingress-Id is only used in the Record Route Object for
recording the proxy-ingress. If no proxy-ingress-id is specified,
then a local interface address that will not otherwise be included
in the Record Route Object can be used. A similar technique is
used in [RFC4090 Sec 6.1.1].
o Application Traffic Identifier: The primary ingress and backup o Application Traffic Identifier: The primary ingress and backup
ingress MUST both know what application traffic should be directed ingress MUST both know what application traffic should be directed
into the LSP. If a list of prefixes in the Traffic Descriptor into the LSP. If a list of prefixes in the Traffic Descriptor
sub-object will not suffice, then a commonly understood sub-object will not suffice, then a commonly understood
Application Traffic Identifier can be sent between the primary Application Traffic Identifier can be sent between the primary
ingress and backup ingress. The exact meaning of the identifier ingress and backup ingress. The exact meaning of the identifier
should be configured similarly at both the primary ingress and should be configured similarly at both the primary ingress and
backup ingress. The Application Traffic Identifier is understood backup ingress. The Application Traffic Identifier is understood
within the unique context of the primary ingress and backup within the unique context of the primary ingress and backup
ingress. ingress.
With this additional information, the primary ingress can create and With this additional information, the primary ingress can create and
signal the necessary RSVP extensions to support ingress protection. signal the necessary RSVP extensions to support ingress protection.
6.2.1. Relay-Message Method The primary ingress relays the information for ingress protection of
an LSP to the backup ingress via PATH messages. Once the LSP is
created, the ingress of the LSP sends the backup ingress a PATH
message with an INGRESS_PROTECTION object with Label-Routes
subobject, which is populated with the next-hops and labels. This
provides sufficient information for the backup ingress to create the
appropriate forwarding state and backup LSP(s).
The ingress also sends the backup ingress all the other PATH messages
for the LSP with an empty INGRESS_PROTECTION object. Thus, the
backup ingress has access to all the PATH messages needed for
modification to refresh control-plane state after a failure.
To protect the ingress of an LSP, the ingress MUST do the following To protect the ingress of an LSP, the ingress MUST do the following
after the LSP is up. after the LSP is up.
1. Select a PATH message. 1. Select a PATH message.
2. If the backup ingress is off-path, then send it a PATH message 2. If the backup ingress is off-path, then send it a PATH message
with the content from the selected PATH message and an with the content from the selected PATH message and an
INGRESS_PROTECTION object; else (the backup ingress is a next INGRESS_PROTECTION object; else (the backup ingress is a next
hop, i.e., on-path case) add an INGRESS_PROTECTION object into hop, i.e., on-path case) add an INGRESS_PROTECTION object into
the existing PATH message to the backup ingress (i.e., the next the existing PATH message to the backup ingress (i.e., the next
hop). The object contains the Traffic-Descriptor sub-object, the hop). The object contains the Traffic-Descriptor sub-object, the
Backup Ingress Address sub-object and the Label-Routes sub- Backup Ingress Address sub-object and the Label-Routes sub-
object. The options is set to indicate whether a Backup P2MP LSP object. The options is set to indicate whether a Backup P2MP LSP
is desired. A secondary LSP-ID is allocated (if it is not is desired. The Label-Routes sub-object contains the next-hops
allocated yet) and used in the object. The Label-Routes sub- of the ingress and their labels.
object contains the next-hops of the ingress and their labels.
3. For each of the other PATH messages, send the backup ingress a 3. For each of the other PATH messages, send the backup ingress a
PATH message with the content copied from the message and an PATH message with the content copied from the message and an
empty INGRESS_PROTECTION object, which is an object without any empty INGRESS_PROTECTION object, which is an object without any
Traffic-Descriptor sub-object. Traffic-Descriptor sub-object.
6.2.2. Proxy-Ingress Method 6.2. Backup Ingress Behavior
The primary ingress is responsible for starting the RSVP signaling
for the proxy-ingress node. To do this, the following MUST be done
for the RSVP PATH message.
1. Compute the EROs for the LSP as normal for the ingress.
2. If the selected backup ingress node is not the first node on the
path (for all sub-LSPs), then insert at the beginning of the ERO
first the backup ingress node and then the ingress node.
3. In the PATH RRO, instead of recording the ingress node's address,
replace it with the Proxy-Ingress-Id.
4. Leave the HOP object populated as usual with information for the
ingress-node.
5. Add the INGRESS_PROTECTION object to the PATH message. Allocate
a secondary LSP-ID to be used in the INGRESS-PROTECTION object.
Include the Backup Ingress Address (IPv4 or IPv6) sub-object and
the Traffic-Descriptor sub-object. Set or clear the options
indicating that a Backup P2MP LSP is desired.
6. Optionally, add the FAST-REROUTE object [RFC4090] to the Path
message. Indicate whether one-to-one backup is desired.
Indicate whether facility backup is desired.
7. The RSVP PATH message is sent to the backup node as normal.
If the ingress detects that it can't communicate with the backup
ingress, then the ingress SHOULD instead send the PATH message to the
next-hop indicated in the ERO computed in step 1. Once the ingress
detects that it can communicate with the backup ingress, the ingress
SHOULD follow the steps 1-7 to obtain ingress failure protection.
When the ingress node receives an RSVP PATH message with an INGRESS-
PROTECTION object and the object specifies that node as the ingress
node and the PHOP as the backup ingress node, the ingress node SHOULD
remove the INGRESS_PROTECTION object from the PATH message before
sending it out. Additionally, the ingress node MUST store that it
will install ingress forwarding state for the LSP rather than
midpoint forwarding.
When an RSVP RESV message is received by the ingress, it uses the
NHOP to determine whether the message is received from the backup
ingress or from a different node. The stored associated PATH message
contains an INGRESS_PROTECTION object that identifies the backup
ingress node. If the RESV message is not from the backup node, then
ingress forwarding state SHOULD be set up, and the INGRESS_PROTECTION
object MUST be added to the RESV before it is sent to the NHOP, which
SHOULD be the backup node. If the RESV message is from the backup
node, then the LSP SHOULD be considered available for use.
If the backup ingress node is on the forwarding path, then a RESV is
received with an INGRESS_PROTECTION object and an NHOP that matches
the backup ingress. In this case, the ingress node's address will
not appear after the backup ingress in the RRO. The ingress node
SHOULD set up ingress forwarding state, just as is done if the LSP
weren't ingress-node protected.
6.3. Backup Ingress Behavior
An LER determines that the ingress local protection is requested for An LER determines that the ingress local protection is requested for
an LSP if the INGRESS_PROTECTION object is included in the PATH an LSP if the INGRESS_PROTECTION object is included in the PATH
message it receives for the LSP. The LER can further determine that message it receives for the LSP. The LER can further determine that
it is the backup ingress if one of its addresses is in the Backup it is the backup ingress if one of its addresses is in the Backup
Ingress Address sub-object of the INGRESS_PROTECTION object. The LER Ingress Address sub-object of the INGRESS_PROTECTION object. The LER
as the backup ingress will assume full responsibility of the ingress as the backup ingress will assume full responsibility of the ingress
after the primary ingress fails. In addition, the LER determines after the primary ingress fails. In addition, the LER determines
that it is off-path if it is not any node of the LSP. that it is off-path if it is not any node of the LSP.
6.3.1. Backup Ingress Behavior in Off-path Case 6.2.1. Backup Ingress Behavior in Off-path Case
The backup ingress considers itself as a PLR and the primary ingress The backup ingress considers itself as a PLR and the primary ingress
as its next hop and provides a local protection for the primary as its next hop and provides a local protection for the primary
ingress. It behaves very similarly to a PLR providing fast-reroute ingress. It behaves very similarly to a PLR providing fast-reroute
where the primary ingress is considered as the failure-point to where the primary ingress is considered as the failure-point to
protect. Where not otherwise specified, the behavior given in protect. Where not otherwise specified, the behavior given in
[RFC4090] for a PLR applies. [RFC4090] for a PLR applies.
The backup ingress MUST follow the control-options specified in the The backup ingress MUST follow the control-options specified in the
INGRESS_PROTECTION object and the flags and specifications in the INGRESS_PROTECTION object and the flags and specifications in the
skipping to change at page 16, line 23 skipping to change at page 13, line 16
primary ingress, and tear down the one-to-one backup LSPs for primary ingress, and tear down the one-to-one backup LSPs for
protecting the primary ingress if one-to-one backup is used or unbind protecting the primary ingress if one-to-one backup is used or unbind
the facility backup LSPs if facility backup is used. the facility backup LSPs if facility backup is used.
When the backup ingress receives a PATH message from the primary When the backup ingress receives a PATH message from the primary
ingress for locally protecting the primary ingress of a protected ingress for locally protecting the primary ingress of a protected
LSP, it MUST check to see if any critical information has been LSP, it MUST check to see if any critical information has been
changed. If the next hops of the primary ingress are changed, the changed. If the next hops of the primary ingress are changed, the
backup ingress SHALL update its backup LSP(s) accordingly. backup ingress SHALL update its backup LSP(s) accordingly.
6.3.1.1. Relay-Message Method
When the backup ingress receives a PATH message with an non empty When the backup ingress receives a PATH message with an non empty
INGRESS_PROTECTION object, it examines the object to learn what INGRESS_PROTECTION object, it examines the object to learn what
traffic associated with the LSP. It determines the next-hops to be traffic associated with the LSP. It determines the next-hops to be
merged to by examining the Label-Routes sub-object in the object. merged to by examining the Label-Routes sub-object in the object.
The backup ingress MUST store the PATH message received from the The backup ingress MUST store the PATH message received from the
primary ingress, but NOT forward it. primary ingress, but NOT forward it.
The backup ingress responds with a RESV to the PATH message received The backup ingress responds with a RESV to the PATH message received
from the primary ingress. If the INGRESS_PROTECTION object is not from the primary ingress. If the INGRESS_PROTECTION object is not
"empty", the backup ingress SHALL send the RESV message with the "empty", the backup ingress SHALL send the RESV message with the
state indicating protection is available after the backup LSP(s) are state indicating protection is available after the backup LSP(s) are
successfully established. successfully established.
6.3.1.2. Proxy-Ingress Method 6.2.2. Backup Ingress Behavior in On-path Case
The backup ingress determines the next-hops to be merged to by
collecting the set of the pair of (IPv4/IPv6 sub-object, Label sub-
object) from the Record Route Object of each RESV that are closest to
the top and not the Ingress router; this should be the second to the
top pair. If a Label-Routes sub-object is included in the
INGRESS_PROTECTION object, the included IPv4/IPv6 sub-objects are
used to filter the set down to the specific next-hops where
protection is desired. A RESV message MUST have been received before
the Backup Ingress can create or select the appropriate backup LSP.
When the backup ingress receives a PATH message with the
INGRESS_PROTECTION object, the backup ingress examines the object to
learn what traffic associated with the LSP. The backup ingress
forwards the PATH message to the ingress node with the normal RSVP
changes.
When the backup ingress receives a RESV message with the
INGRESS_PROTECTION object, the backup ingress records an IMPLICIT-
NULL label in the RRO. Then the backup ingress forwards the RESV
message to the ingress node, which is acting for the proxy ingress.
6.3.2. Backup Ingress Behavior in On-path Case
An LER as the backup ingress determines that it is on-path if one of An LER as the backup ingress determines that it is on-path if one of
its addresses is a next hop of the primary ingress (and for Proxy- its addresses is a next hop of the primary ingress. The LER on-path
Ingress Method the primary ingress is not its next hop via checking MUST send the corresponding PATH messages without any
the PATH message with the INGRESS_PROTECTION object received from the INGRESS_PROTECTION object to its next hops. It creates a number of
primary ingress). The LER on-path MUST send the corresponding PATH backup P2P LSPs or a backup P2MP LSP from itself to the other next
messages without any INGRESS_PROTECTION object to its next hops. It hops (i.e., the next hops other than the backup ingress) of the
creates a number of backup P2P LSPs or a backup P2MP LSP from itself primary ingress. The other next hops are from the Label-Routes sub
to the other next hops (i.e., the next hops other than the backup object.
ingress) of the primary ingress. The other next hops are from the
Label-Routes sub object.
It also creates a forwarding entry, which sends/multicasts the It also creates a forwarding entry, which sends/multicasts the
traffic from the source to the next hops of the backup ingress along traffic from the source to the next hops of the backup ingress along
the protected LSP when the primary ingress fails. The traffic is the protected LSP when the primary ingress fails. The traffic is
described by the Traffic-Descriptor. described by the Traffic-Descriptor.
After the forwarding entry is created, all the backup P2P LSPs or the After the forwarding entry is created, all the backup P2P LSPs or the
backup P2MP LSP is up and associated with the protected LSP, the backup P2MP LSP is up and associated with the protected LSP, the
backup ingress MUST send the primary ingress the RESV message with backup ingress MUST send the primary ingress the RESV message with
the INGRESS_PROTECTION object containing the state of the local the INGRESS_PROTECTION object containing the state of the local
skipping to change at page 18, line 5 skipping to change at page 14, line 18
backup P2MP LSP transmitting the traffic to the other next hops of backup P2MP LSP transmitting the traffic to the other next hops of
the primary ingress, where the traffic is merged into protected LSP. the primary ingress, where the traffic is merged into protected LSP.
During the local repair, the backup ingress MUST continue to send the During the local repair, the backup ingress MUST continue to send the
PATH messages to its next hops as before, keep the PATH message with PATH messages to its next hops as before, keep the PATH message with
the INGRESS_PROTECTION object received from the primary ingress and the INGRESS_PROTECTION object received from the primary ingress and
the RESV message with the INGRESS_PROTECTION object to be sent to the the RESV message with the INGRESS_PROTECTION object to be sent to the
primary ingress. It MUST set the "local protection in use" flag in primary ingress. It MUST set the "local protection in use" flag in
the RESV message. the RESV message.
6.3.3. Failure Detection and Refresh PATH Messages 6.2.3. Failure Detection and Refresh PATH Messages
As described in [RFC4090], it is necessary to refresh the PATH As described in [RFC4090], it is necessary to refresh the PATH
messages via the backup LSP(s). The Backup Ingress MUST wait to messages via the backup LSP(s). The Backup Ingress MUST wait to
refresh the PATH messages until it can accurately detect that the refresh the PATH messages until it can accurately detect that the
ingress node has failed. An example of such an accurate detection ingress node has failed. An example of such an accurate detection
would be that the IGP has no bi-directional links to the ingress node would be that the IGP has no bi-directional links to the ingress node
and the last change was long enough in the past that changes should and the last change was long enough in the past that changes should
have been received (i.e., an IGP network convergence time or have been received (i.e., an IGP network convergence time or
approximately 2-3 seconds) or a BFD session to the primary ingress' approximately 2-3 seconds) or a BFD session to the primary ingress'
loopback address has failed and stayed failed after the network has loopback address has failed and stayed failed after the network has
reconverged. reconverged.
As described in [RFC4090 Section 6.4.3], the backup ingress, acting As described in [RFC4090 Section 6.4.3], the backup ingress, acting
as PLR, MUST modify and send any saved PATH messages associated with as PLR, MUST modify and send any saved PATH messages associated with
the primary LSP to the corresponding next hops through backup LSP(s). the primary LSP to the corresponding next hops through backup LSP(s).
Any PATH message sent will not contain any INGRESS_PROTECTION object. Any PATH message sent will not contain any INGRESS_PROTECTION object.
The RSVP_HOP object in the message contains an IP source address The RSVP_HOP object in the message contains an IP source address
belonging to the backup ingress. The sender template object has the belonging to the backup ingress. The sender template object has the
backup ingress address as its tunnel sender address. backup ingress address as its tunnel sender address.
6.4. Revertive Behavior 6.3. Revertive Behavior
Upon a failure event in the (primary) ingress of a protected LSP, the Upon a failure event in the (primary) ingress of a protected LSP, the
protected LSP is locally repaired by the backup ingress. There are a protected LSP is locally repaired by the backup ingress. There are a
couple of basic strategies for restoring the LSP to a full working couple of basic strategies for restoring the LSP to a full working
path. path.
- Revert to Primary Ingress: When the primary ingress is restored, - Revert to Primary Ingress: When the primary ingress is restored,
it re-signals each of the LSPs that start from the primary it re-signals each of the LSPs that start from the primary
ingress. The traffic for every LSP successfully re-signaled is ingress. The traffic for every LSP successfully re-signaled is
switched back to the primary ingress from the backup ingress. switched back to the primary ingress from the backup ingress.
- Global Repair by Backup Ingress: After determining that the - Global Repair by Backup Ingress: After determining that the
primary ingress of an LSP has failed, the backup ingress computes primary ingress of an LSP has failed, the backup ingress computes
a new optimal path, signals a new LSP along the new path, and a new optimal path, signals a new LSP along the new path, and
switches the traffic to the new LSP. switches the traffic to the new LSP.
6.4.1. Revert to Primary Ingress 6.3.1. Revert to Primary Ingress
If "Revert to Primary Ingress" is desired for a protected LSP, the If "Revert to Primary Ingress" is desired for a protected LSP, the
(primary) ingress of the LSP SHOULD re-signal the LSP that starts (primary) ingress of the LSP SHOULD re-signal the LSP that starts
from the primary ingress after the primary ingress restores. After from the primary ingress after the primary ingress restores. After
the LSP is re-signaled successfully, the traffic SHOULD be switched the LSP is re-signaled successfully, the traffic SHOULD be switched
back to the primary ingress from the backup ingress on the source back to the primary ingress from the backup ingress on the source
node and redirected into the LSP starting from the primary ingress. node and redirected into the LSP starting from the primary ingress.
The primary ingress can specify the "Revert to Ingress" control- The primary ingress can specify the "Revert to Ingress" control-
option in the INGRESS_PROTECTION object in the PATH messages to the option in the INGRESS_PROTECTION object in the PATH messages to the
backup ingress. After receiving the "Revert to Ingress" control- backup ingress. After receiving the "Revert to Ingress" control-
option, the backup ingress MUST stop sending/refreshing PATH messages option, the backup ingress MUST stop sending/refreshing PATH messages
for the protected LSP. for the protected LSP.
6.4.2. Global Repair by Backup Ingress 6.3.2. Global Repair by Backup Ingress
When the backup ingress has determined that the primary ingress of When the backup ingress has determined that the primary ingress of
the protected LSP has failed (e.g., via the IGP), it can compute a the protected LSP has failed (e.g., via the IGP), it can compute a
new path and signal a new LSP along the new path so that it no longer new path and signal a new LSP along the new path so that it no longer
relies upon local repair. To do this, the backup ingress MUST use relies upon local repair. To do this, the backup ingress MUST use
the same tunnel sender address in the Sender Template Object and the the same tunnel sender address in the Sender Template Object and
previously allocated secondary LSP-ID in the INGRESS_PROTECTION allocate a LSP ID different from the one of the old LSP as the LSP-ID
object of the PATH message as the LSP-ID of the new LSP. This allows of the new LSP. This allows the new LSP to share resources with the
the new LSP to share resources with the old LSP. In addition, if the old LSP. In addition, if the Ingress recovers, the Backup Ingress
Ingress recovers, the Backup Ingress SHOULD send it RESVs with the SHOULD send it RESVs with the INGRESS_PROTECTION object where the
INGRESS_PROTECTION object where the "Revert to Ingress" is specified. "Revert to Ingress" is specified. The Ingress can learn from the
The Secondary LSP ID MUST be the unused LSP ID - while the LSP ID RESVs what to signal. The Backup Ingress can reoptimize the new LSP
signaled in the RESV will be that currently active. The Ingress can as necessary until the Ingress recovers. Alternately, the Backup
learn from the RESVs what to signal. Even if the Ingress does not Ingress can create a new LSP with no bandwidth reservation that
take over, the RESVs notify it that the particular LSP IDs are in duplicates the path(s) of the protected LSP, move traffic to the new
use. The Backup Ingress can reoptimize the new LSP as necessary LSP, delete the protected LSP, and then resignal the new LSP with
until the Ingress recovers. Alternately, the Backup Ingress can bandwidth.
create a new LSP with no bandwidth reservation that duplicates the
path(s) of the protected LSP, move traffic to the new LSP, delete the
protected LSP, and then resignal the new LSP with bandwidth.
7. Security Considerations 7. Security Considerations
In principle this document does not introduce new security issues. In principle this document does not introduce new security issues.
The security considerations pertaining to RFC 4090, RFC 4875 and The security considerations pertaining to RFC 4090, RFC 4875 and
other RSVP protocols remain relevant. other RSVP protocols remain relevant.
8. IANA Considerations 8. IANA Considerations
IANA is requested to administer the assignment of new values defined IANA is requested to administer the assignment of new values defined
skipping to change at page 21, line 31 skipping to change at page 17, line 42
The authors would like to thank Nobo Akiya, Rahul Aggarwal, Eric The authors would like to thank Nobo Akiya, Rahul Aggarwal, Eric
Osborne, Ross Callon, Loa Andersson, Daniel King, Michael Yue, Osborne, Ross Callon, Loa Andersson, Daniel King, Michael Yue,
Olufemi Komolafe, Rob Rennison, Neil Harrison, Kannan Sampath, Olufemi Komolafe, Rob Rennison, Neil Harrison, Kannan Sampath,
Gregory Mirsky, and Ronhazli Adam for their valuable comments and Gregory Mirsky, and Ronhazli Adam for their valuable comments and
suggestions on this draft. suggestions on this draft.
11. Normative References 11. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol [RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
Label Switching Architecture", RFC 3031, January 2001. Label Switching Architecture", RFC 3031, DOI 10.17487/
RFC3031, January 2001,
<http://www.rfc-editor.org/info/rfc3031>.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, December 2001. Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001,
<http://www.rfc-editor.org/info/rfc3209>.
[RFC4090] Pan, P., Swallow, G., and A. Atlas, "Fast Reroute [RFC4090] Pan, P., Ed., Swallow, G., Ed., and A. Atlas, Ed., "Fast
Extensions to RSVP-TE for LSP Tunnels", RFC 4090, Reroute Extensions to RSVP-TE for LSP Tunnels", RFC 4090,
May 2005. DOI 10.17487/RFC4090, May 2005,
<http://www.rfc-editor.org/info/rfc4090>.
[RFC4875] Aggarwal, R., Papadimitriou, D., and S. Yasukawa, [RFC4875] Aggarwal, R., Ed., Papadimitriou, D., Ed., and S.
"Extensions to Resource Reservation Protocol - Traffic Yasukawa, Ed., "Extensions to Resource Reservation
Engineering (RSVP-TE) for Point-to-Multipoint TE Label Protocol - Traffic Engineering (RSVP-TE) for Point-to-
Switched Paths (LSPs)", RFC 4875, May 2007. Multipoint TE Label Switched Paths (LSPs)", RFC 4875,
DOI 10.17487/RFC4875, May 2007,
<http://www.rfc-editor.org/info/rfc4875>.
Appendix A. Authors' Addresses Appendix A. Authors' Addresses
Huaimo Chen Huaimo Chen
Huawei Technologies Huawei Technologies
Boston, MA Boston, MA
USA USA
Email: huaimo.chen@huawei.com Email: huaimo.chen@huawei.com
Raveendra Torvi Raveendra Torvi
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