draft-chen-mpls-p2mp-egress-protection-10.txt   draft-chen-mpls-p2mp-egress-protection-11.txt 
Internet Engineering Task Force H. Chen Internet Engineering Task Force H. Chen
Internet-Draft Huawei Technologies Internet-Draft Huawei Technologies
Intended status: Standards Track N. So Intended status: Standards Track N. So
Expires: June 1, 2014 Tata Communications Expires: August 14, 2014 Tata Communications
A. Liu A. Liu
Ericsson Ericsson
F. Xu F. Xu
Verizon Verizon
M. Toy M. Toy
Comcast Comcast
L. Huang L. Huang
China Mobile China Mobile
L. Liu L. Liu
UC Davis UC Davis
November 28, 2013 February 10, 2014
Extensions to RSVP-TE for LSP Egress Local Protection Extensions to RSVP-TE for LSP Egress Local Protection
draft-chen-mpls-p2mp-egress-protection-10.txt draft-chen-mpls-p2mp-egress-protection-11.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 egress nodes of Traffic Engineering (RSVP-TE) for locally protecting egress nodes of
a Traffic Engineered (TE) Label Switched Path (LSP) in a Multi- a Traffic Engineered (TE) Label Switched Path (LSP) in a Multi-
Protocol Label Switching (MPLS) and Generalized MPLS (GMPLS) network. Protocol Label Switching (MPLS) and Generalized MPLS (GMPLS) network.
Status of this Memo Status of this Memo
skipping to change at page 1, line 44 skipping to change at page 1, line 44
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Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. An Example of Egress Local Protection . . . . . . . . . . 3 1.1. An Example of Egress Local Protection . . . . . . . . . . 3
1.2. Egress Local Protection with FRR . . . . . . . . . . . . . 4 1.2. Egress Local Protection with FRR . . . . . . . . . . . . . 4
2. Protocol Extensions . . . . . . . . . . . . . . . . . . . . . 4 2. Conventions Used in This Document . . . . . . . . . . . . . . 4
2.1. EGRESS_BACKUP_SUB_LSP IPv4/IPv6 Object . . . . . . . . . . 4 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2. EGRESS_BACKUP_SECONDARY_EXPLICIT_ROUTE Object . . . . . . 5 4. Protocol Extensions . . . . . . . . . . . . . . . . . . . . . 4
2.3. Path Message . . . . . . . . . . . . . . . . . . . . . . . 6 4.1. EGRESS_BACKUP Object . . . . . . . . . . . . . . . . . . . 4
3. Egress Protection Behaviors . . . . . . . . . . . . . . . . . 6 4.2. Flags in FAST_REROUTE . . . . . . . . . . . . . . . . . . 6
3.1. Ingress Behavior . . . . . . . . . . . . . . . . . . . . . 7 4.3. Path Message . . . . . . . . . . . . . . . . . . . . . . . 6
3.2. Intermediate Node and PLR Behavior . . . . . . . . . . . . 7 5. Egress Protection Behaviors . . . . . . . . . . . . . . . . . 6
3.2.1. Signaling for One-to-One Protection . . . . . . . . . 8 5.1. Ingress Behavior . . . . . . . . . . . . . . . . . . . . . 6
3.2.2. Signaling for Facility Protection . . . . . . . . . . 8 5.2. Intermediate Node and PLR Behavior . . . . . . . . . . . . 7
3.2.3. Signaling for S2L Sub LSP Protection . . . . . . . . . 9 5.2.1. Signaling for One-to-One Protection . . . . . . . . . 8
3.2.4. PLR Procedures during Local Repair . . . . . . . . . . 9 5.2.2. Signaling for Facility Protection . . . . . . . . . . 8
4. Considering Application Traffic . . . . . . . . . . . . . . . 10 5.2.3. Signaling for S2L Sub LSP Protection . . . . . . . . . 9
4.1. A Typical Application . . . . . . . . . . . . . . . . . . 10 5.2.4. PLR Procedures during Local Repair . . . . . . . . . . 10
4.2. PLR Procedure for Applications . . . . . . . . . . . . . . 11 6. Considering Application Traffic . . . . . . . . . . . . . . . 10
4.3. Egress Procedures for Applications . . . . . . . . . . . . 11 6.1. A Typical Application . . . . . . . . . . . . . . . . . . 10
5. Security Considerations . . . . . . . . . . . . . . . . . . . 12 6.2. PLR Procedure for Applications . . . . . . . . . . . . . . 11
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 6.3. Egress Procedures for Applications . . . . . . . . . . . . 11
7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 12 7. Security Considerations . . . . . . . . . . . . . . . . . . . 12
8. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 12 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 12
9.1. Normative References . . . . . . . . . . . . . . . . . . . 13 10. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 13
9.2. Informative References . . . . . . . . . . . . . . . . . . 13 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
11.1. Normative References . . . . . . . . . . . . . . . . . . . 13
11.2. Informative References . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction 1. Introduction
RFC 4090 describes two methods for protecting the transit nodes of a RFC 4090 describes two methods for protecting the transit nodes of a
P2P LSP: one-to-one protection and facility bypass protection. RFC P2P LSP: one-to-one and facility protection. RFC 4875 specifies how
4875 specifies how to use them to protect the transit nodes of a P2MP to use them to protect the transit nodes of a P2MP LSP. However,
LSP. However, there is no mention of locally protecting any egress they do not mention any local protection for an egress of an LSP.
of a protected P2P or P2MP LSP in these RFCs.
To protect the egresses of an LSP (P2P or P2MP), an existing approach To protect the egresses of an LSP (P2P or P2MP), an existing approach
sets up a backup LSP from a backup ingress (or the ingress of the sets up a backup LSP from a backup ingress (or the ingress of the
LSP) to the backup egresses, where each egress is paired with a LSP) to the backup egresses, where each egress is paired with a
backup egress and protected by the backup egress. backup egress and protected by the backup egress.
The main disadvantage of this approach is that more network resources This approach may use more resources and provide slow fault recovery.
such as double bandwidths may be used. This document specifies extensions to RSVP-TE for local protection of
an egress of an LSP, which overcomes these disadvantages.
This document specifies extensions to RSVP-TE for locally protecting
an egress of a P2MP or P2P LSP, which overcome this disadvantage.
1.1. An Example of Egress Local Protection 1.1. An Example of Egress Local Protection
Figure 1 illustrates an example of using backup LSPs to locally Figure 1 shows an example of using backup LSPs to locally protect
protect egress nodes of a primary P2MP LSP, which is from ingress egresses of a primary P2MP LSP from ingress R1 to two egresses: L1
node R1 to two egress nodes: L1 and L2. The primary LSP is and L2. The primary LSP is represented by star(*) lines and backup
represented by star(*) lines and backup LSPs by hyphen(-) lines. LSPs by hyphen(-) lines.
La and Lb are the designated backup egress nodes for egress nodes L1
and L2 of the P2MP LSP respectively. To distinguish between an
egress (e.g., L1 in the figure) and a backup egress (e.g., La in the
figure), an egress is called a primary egress if necessary.
The backup LSP for protecting primary egress L1 is from its upstream
node R3 to backup egress La. The backup LSP for protecting primary
egress L2 is from its upstream node R5 to backup egress Lb.
During normal operations, the traffic carried by the P2MP LSP is sent La and Lb are the designated backup egresses for egresses L1 and L2
through R3 to L1, which delivers the traffic to its destination CE1. respectively. To distinguish an egress (e.g., L1) from a backup
When R3 detects the failure of L1, R3 switches the traffic to the egress (e.g., La), an egress is called a primary egress if needed.
backup LSP to backup egress La, which delivers the traffic to CE1.
The time for switching the traffic is within tens of milliseconds.
The failure of a primary egress (e.g., L1 in the figure) MAY be The backup LSP for protecting L1 is from its upstream node R3 to
detected by its upstream node (e.g., R3 in the figure) through a BFD backup egress La. The one for protecting L2 is from R5 to Lb.
session between the upstream node and the egress in MPLS networks.
Exactly how the failure is detected is out of scope for this
document.
[R2]*****[R3]*****[L1] [R2]*****[R3]*****[L1]
* \ :.....: $ **** Primary LSP * \ :.....: $ **** Primary LSP
* \ $ ---- Backup LSP * \ $ ---- Backup LSP
* \ [CE1] .... BFD Session * \ [CE1] .... BFD Session
* \ $ $ Link * \ $ $ Link
* \ $ $ * \ $ $
* [La] $ * [La] $
* *
[R1]******[R4]*******[R5]*****[L2] [R1]******[R4]*******[R5]*****[L2]
$ \ :.....: $ $ \ :.....: $
$ \ $ $ \ $
[S] \ [CE2] [S] \ [CE2]
\ $ \ $
\ $ \ $
[Lb] [Lb]
Figure 1: Backup LSP for Locally Protecting Egress Figure 1: Backup LSP for Locally Protecting Egress
During normal operations, the traffic carried by the P2MP LSP is sent
through R3 to L1, which delivers the traffic to its destination CE1.
When R3 detects the failure of L1, R3 switches the traffic to the
backup LSP to backup egress La, which delivers the traffic to CE1.
The time for switching the traffic is within tens of milliseconds.
The failure of a primary egress (e.g., L1 in the figure) MAY be
detected by its upstream node (e.g., R3 in the figure) through a BFD
between the upstream node and the egress in MPLS networks. Exactly
how the failure is detected is out of scope for this document.
1.2. Egress Local Protection with FRR 1.2. Egress Local Protection with FRR
Using the egress local protection and the FRR, we can locally protect Using the egress local protection and the FRR, we can locally protect
the egresses, the links and the intermediate nodes of an LSP. The the egresses, the links and the intermediate nodes of an LSP. The
traffic switchover time is within tens of milliseconds whenever an traffic switchover time is within tens of milliseconds whenever an
egress, any of the links and the intermediate nodes of the LSP fails. egress, any of the links and the intermediate nodes of the LSP fails.
The egress nodes of the LSP can be locally protected via the egress The egress nodes of the LSP can be locally protected via the egress
local protection. All the links and the intermediate nodes of the local protection. All the links and the intermediate nodes of the
LSP can be locally protected through using the FRR. LSP can be locally protected through using the FRR.
2. Protocol Extensions 2. Conventions Used in This Document
A new object EGRESS_BACKUP_SUB_LSP is defined for signaling egress The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
local protection. It contains a backup egress for a primary egress. "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119.
2.1. EGRESS_BACKUP_SUB_LSP IPv4/IPv6 Object 3. Terminology
The class of the EGRESS_BACKUP_SUB_LSP IPv4/IPv6 object is 50, which This document uses terminologies defined in RFC 2205, RFC 3031, RFC
is the same as that of the S2L_SUB_LSP IPv4/IPv6 object defined in 3209, RFC 3473, RFC 4090, RFC 4461, and RFC 4875.
RFC 4875. The C-Type of the EGRESS_BACKUP_SUB_LSP IPv4 object is a
new number 3 or another number assigned by IANA.
EGRESS_BACKUP_SUB_LSP_IPv4 C-Type = 3 4. Protocol Extensions
0 1 2 3 A new object EGRESS_BACKUP is defined for egress local protection.
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 It contains a backup egress for a primary egress.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Egress Backup Sub LSP destination IPv4 address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Egress Primary Sub LSP destination IPv4 address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| (Subobjects) |
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Egress Backup Sub LSP destination IPv4 address 4.1. EGRESS_BACKUP Object
IPv4 address of the backup egress node
Egress Primary Sub LSP destination IPv4 address
IPv4 address of the primary egress node
Subobjects are optional
The C-Type of the EGRESS_BACKUP_SUB_LSP IPv6 object is a new number 4 The class of the EGRESS_BACKUP object is TBD-1 to be assigned by
or another number assigned by IANA. IANA. The C-Type of the EGRESS_BACKUP IPv4/IPv6 object is TBD-2/
TBD-3 to be assigned by IANA.
EGRESS_BACKUP_SUB_LSP_IPv6 C-Type = 4 EGRESS_BACKUP Class Num = TBD-1, IPv4/IPv6 C-Type = TBD-2/TBD-3
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Egress Backup Sub LSP destination IPv6 address | ~ Egress Backup destination IPv4/IPv6 address ~
~ (16 bytes) ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Egress Primary destination IPv4/IPv6 address ~
| Egress Primary Sub LSP destination IPv6 address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ (16 bytes) ~ ~ (Subobjects) ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| (Subobjects) |
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Egress Backup Sub LSP destination IPv6 address o Egress Backup destination IPv4/IPv6 address:
IPv6 address of the backup egress node IPv4/IPv6 address of the backup egress node
Egress Primary Sub LSP destination IPv6 address o Egress Primary destination IPv4/IPv6 address:
IPv6 address of the primary egress node IPv4/IPv6 address of the primary egress node
Subobjects are optional
2.2. EGRESS_BACKUP_SECONDARY_EXPLICIT_ROUTE Object The Subobjects are optional. One of them is P2P LSP ID IPv4/IPv6
subobject, whose body has the following format and Type is TBD-4/
TBD-5. It may be used to identify a backup LSP.
An EGRESS_BACKUP_SECONDARY_EXPLICIT_ROUTE (EB-SERO) object is defined 0 1 2 3
for signaling protection for a primary egress of a P2MP LSP in a new 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
S2L Sub LSP backup protection method. It contains a path from the +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
upstream node of the primary egress to a backup egress. Its format ~ P2P LSP Tunnel Egress IPv4/IPv6 Address (4/16 bytes) ~
is identical to an ERO's. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Tunnel ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Extended Tunnel ID (4/16 bytes) ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The class of an EB-SERO is the same as that of a SERO defined in RFC o P2P LSP Tunnel Egress IPv4/IPv6 Address:
4873. The EB-SERO uses a new C-Type 3, or another number assigned by IPv4/IPv6 address of the egress of the tunnel
IANA. The formats of sub-objects in an EB-SERO are identical to o Tunnel ID:
those of sub-objects in an ERO defined in RFC 3209. A 16-bit identifier that is constant over the life of the tunnel
o Extended Tunnel ID:
A 4/16-byte identifier being constant over the life of the tunnel
2.3. Path Message Another one is Label subobject, whose body has the format below and
Type is TBD-6 to be assigned by IANA.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4.2. Flags in FAST_REROUTE
A bit of the flags in the FAST_REROUTE object may be used to indicate
whether S2L Sub LSP is desired for protecting an egress of a P2MP LSP
or One-to-One Backup is preferred for protecting an egress of a P2P
LSP when the "Facility Backup Desired" flag is set. This bit is
called "S2L Sub LSP Backup Desired" or "One-to-One Backup Preferred".
4.3. Path Message
A Path message is enhanced to carry the information about a backup A Path message is enhanced to carry the information about a backup
egress for a primary egress of an LSP through including an egress egress for a primary egress of an LSP through including an egress
backup sub LSP descriptor list. The format of the enhanced Path backup descriptor list. The format of the enhanced Path message is
message is illustrated below. illustrated below.
<Path Message> ::= <Common Header> [ <INTEGRITY> ] <Path Message> ::= <Common Header> [ <INTEGRITY> ]
[ [<MESSAGE_ID_ACK> | <MESSAGE_ID_NACK>] ...] [ [<MESSAGE_ID_ACK> | <MESSAGE_ID_NACK>] ...]
[ <MESSAGE_ID> ] [ <MESSAGE_ID> ]<SESSION> <RSVP_HOP> <TIME_VALUES>
<SESSION> <RSVP_HOP> <TIME_VALUES> [ <EXPLICIT_ROUTE> ]
[ <EXPLICIT_ROUTE> ] <LABEL_REQUEST> [ <PROTECTION> ] [ <LABEL_SET> ...]
<LABEL_REQUEST> [ <PROTECTION> ] [ <SESSION_ATTRIBUTE> ] [ <NOTIFY_REQUEST> ]
[ <LABEL_SET> ... ] [ <ADMIN_STATUS> ] [ <POLICY_DATA> ... ]
[ <SESSION_ATTRIBUTE> ] [ <NOTIFY_REQUEST> ] <sender descriptor> [<S2L sub-LSP descriptor list>]
[ <ADMIN_STATUS> ] [ <POLICY_DATA> ... ] [<egress backup descriptor list>]
<sender descriptor>
[<S2L sub-LSP descriptor list>]
[<egress backup sub LSP descriptor list>]
The egress backup sub LSP descriptor list in the message is defined The egress backup descriptor list in the message is defined below.
below. It is a sequence of EGRESS_BACKUP_SUB_LSP objects, each of It is a sequence of EGRESS_BACKUP objects, each of which describes a
which describes a pair of a primary egress and a backup egress. pair of a primary egress and a backup egress.
<egress backup sub LSP descriptor list> ::= <egress backup descriptor list> ::=
<egress backup sub LSP descriptor> <egress backup descriptor>
[ <egress backup sub LSP descriptor list> ] [ <egress backup descriptor list> ]
<egress backup sub LSP descriptor> ::= <egress backup descriptor> ::= <EGRESS_BACKUP>
<EGRESS_BACKUP_SUB_LSP>
[ <EGRESS_BACKUP_SECONDARY_EXPLICIT_ROUTE> ]
3. Egress Protection Behaviors 5. Egress Protection Behaviors
3.1. Ingress Behavior
To protect a primary egress of an LSP, a backup egress must be 5.1. Ingress Behavior
configured on the ingress of the LSP.
The ingress initiates a Path message for the LSP with an egress To protect a primary egress of an LSP, the ingress MUST set the
backup sub LSP descriptor list. For each primary egress of the LSP "label recording desired" flag and the "node protection desired" flag
to be protected, the ingress MUST add an EGRESS_BACKUP_SUB_LSP object in the SESSION_ATTRIBUTE object.
into the list. The object contains the primary egress and the backup
egress for protecting the primary egress.
To protect a primary egress of an LSP via one-to-one backup or If one-to-one backup or facility backup method is desired to protect
facility backup method, the ingress SHOULD include a FAST_REROUTE a primary egress of an LSP, the ingress SHOULD include a FAST_REROUTE
object and set the One-to-One Backup Desired or Facility Backup object and set the "One-to-One Backup Desired" or "Facility Backup
Desired flag. Desired" flag.
To protect a primary egress of a P2MP LSP via S2L Sub LSP backup If S2L Sub LSP backup method is desired to protect a primary egress
method, the ingress SHOULD add an EB-SERO object following the of a P2MP LSP, the ingress SHOULD include a FAST_REROUTE object and
EGRESS_BACKUP_SUB_LSP object into the list. The EB-SERO object set the "S2L Sub LSP Backup Desired" flag.
contains a path from the upstream node of the primary egress to the
backup egress. The ingress computes the path if the P2MP LSP is in
one area; otherwise, the path may be computed by the Path Computation
Element (PCE).
3.2. Intermediate Node and PLR Behavior Note that if "Facility Backup Desired" flag is set for protecting the
intermediate nodes of a primary P2P LSP, but we want to use "One-to-
One Backup" for protecting the egress of the LSP, then the ingress
SHOULD set "One-to-One Backup Preferred" flag.
Optionally, a backup egress may be configured on the ingress of an
LSP to protect a primary egress of the LSP.
The ingress sends a Path message for the LSP with the objects above
and an optional egress backup descriptor list. For each primary
egress of the LSP to be protected, the ingress adds an EGRESS_BACKUP
object into the list if the backup egress is given. The object
contains the primary egress and the backup egress for protecting the
primary egress.
5.2. Intermediate Node and PLR Behavior
If an intermediate node of an LSP receives the Path message with an If an intermediate node of an LSP receives the Path message with an
egress backup sub LSP descriptor list and it is not an upstream node egress backup descriptor list and it is not an upstream node of any
of any primary egress of the LSP, it forwards the list in the message primary egress of the LSP, it forwards the list unchanged.
unchanged.
If the intermediate node is the upstream node of a primary egress to If the intermediate node is the upstream node of a primary egress to
be protected, it gets the backup egress for the primary egress from be protected, it determines the backup egress, obtains a path for the
the EGRESS_BACKUP_SUB_LSP object in the list. It acts as a PLR to backup LSP and sets up the backup LSP along the path.
provide one-to-one or facility backup protection for the primary
egress. It provides one-to-one backup protection if the One-to-One
Backup Desired flag is set in the message; it provides facility
backup protection if the Facility Backup Desired flag is set.
The PLR (upstream node of the primary egress) sets the protection The PLR (upstream node of the primary egress) tries to get the backup
flags in the RRO Sub-object for the primary egress in the Resv egress from EGRESS_BACKUP in the egress backup descriptor list if the
message according to the status of the primary egress and the backup Path message contains the list. If the PLR can not get it, the PLR
LSP protecting the primary egress. For example, it will set the tries to find the backup egress, which is not the primary egress but
"local protection available" and the "node protection" flag to one has the same IP address as the destination IP address of the LSP.
indicating that the primary egress is protected when the backup LSP
to the backup egress is set up for protecting the primary egress.
3.2.1. Signaling for One-to-One Protection Note that the primary egress and the backup egress SHOULD have a same
local address configured, and the cost to the local address on the
backup egress SHOULD be much bigger than the cost to the local
address on the primary egress. Thus another name such as virtual
node based egress protection may be used for egress local protection.
After obtaining the backup egress, the PLR tries to compute a path
from itself to the backup egress.
The PLR then sets up the backup LSP along the path obtained. It
provides one-to-one backup protection for the primary egress if the
"One-to-One Backup Desired" or "One-to-One Backup Preferred" flag is
set in the message; otherwise, it provides facility backup protection
if the "Facility Backup Desired flag" is set.
The PLR sets the protection flags in the RRO Sub-object for the
primary egress in the Resv message according to the status of the
primary egress and the backup LSP protecting the primary egress. For
example, it will set the "local protection available" and the "node
protection" flag indicating that the primary egress is protected when
the backup LSP is up and ready for protecting the primary egress.
5.2.1. Signaling for One-to-One Protection
The behavior of the upstream node of a primary egress of an LSP as a The behavior of the upstream node of a primary egress of an LSP as a
PLR is the same as that of a PLR for one-to-one backup method PLR is the same as that of a PLR for one-to-one backup method
described in RFC 4090 except for that the upstream node creates a described in RFC 4090 except for that the upstream node creates a
backup LSP from itself to a backup egress. backup LSP from itself to a backup egress.
In the case that the LSP is a P2MP LSP and a primary egress of the If the LSP is a P2MP LSP and a primary egress of the LSP is a transit
LSP is a transit node (i.e., bud node), the upstream node of the node (i.e., bud node), the upstream node of the primary egress as a
primary egress as a PLR also creates a backup LSP from itself to each PLR also creates a backup LSP from itself to each of the next hops of
of the next hops of the primary egress. the primary egress.
When the PLR detects a failure in the primary egress, it MUST rapidly When the PLR detects the failure of the primary egress, it MUST
switch the packets from the primary LSP to the backup LSP to the switch the packets from the primary LSP to the backup LSP to the
backup egress. For a failure in the bud node of an P2MP LSP, the PLR backup egress. For the failure of the bud node of a P2MP LSP, the
MUST also rapidly switch the packets to the backup LSPs to the bud PLR MUST also switch the packets to the backup LSPs to the bud node's
node's next hops, where the packets are merged into the primary LSP. next hops, where the packets are merged into the primary LSP.
3.2.2. Signaling for Facility Protection 5.2.2. Signaling for Facility Protection
Except for backup LSP and downstream label, the behavior of the Except for backup LSP and downstream label, the behavior of the
upstream node of the primary egress as a PLR follows the PLR behavior upstream node of the primary egress of a primary LSP as a PLR follows
for facility backup method described in RFC 4090. the PLR behavior for facility backup method described in RFC 4090.
For a number of primary P2P LSPs going through the same PLR to the For a number of primary P2P LSPs going through the same PLR to the
same primary egress, the primary egress of these LSPs may be same primary egress, the primary egress of these LSPs may be
protected by one backup LSP from the PLR to the backup egress protected by one backup LSP from the PLR to the backup egress
designated for protecting the primary egress. designated for protecting the primary egress.
The PLR selects or creates a backup LSP from itself to the backup The PLR selects or creates a backup LSP from itself to the backup
egress. If there exists a backup LSP that satisfies the constraints egress. If there is a backup LSP that satisfies the constraints
given in the Path message, then this one is selected; otherwise, a given in the Path message, then this one is selected; otherwise, a
new backup LSP to the backup egress will be created. new backup LSP to the backup egress will be created.
For a primary LSP carrying IP packets, the PLR does not need any After getting the backup LSP, the PLR associates the backup LSP with
downstream label as an inner label for the LSP when binding the a primary LSP for protecting its primary egress. The PLR records
primary LSP with the backup LSP. When the PLR detects a failure in that the backup LSP is used to protect the primary LSP against its
the primary egress, it redirects the IP packets from the primary LSP primary egress failure and includes an EGRESS_BACKUP object in the
into the backup LSP to the backup egress, where the IP packets are Path message to the primary egress. The object contains the backup
forwarded according to IP destinations in the packets. egress and the backup LSP ID. It indicates that the primary egress
SHOULD send the backup egress the primary LSP label as UA label.
For a primary LSP carrying packets with application or service After receiving the Path message with the EGRESS_BACKUP, the primary
labels, the PLR may not need any downstream label as an inner label egress includes the information about the primary LSP label in the
for the LSP either when binding the primary LSP with the backup LSP. Resv message with an EGRESS_BACKUP object as UA label. When the PLR
When the PLR detects a failure in the primary egress, it redirects receives the Resv message with the information about the UA label, it
includes the information in the Path message for the backup LSP to
the backup egress. Thus the primary LSP label as UA label is sent to
the backup egress from the primary egress.
When the PLR detects the failure of the primary egress, it redirects
the packets from the primary LSP into the backup LSP to backup egress the packets from the primary LSP into the backup LSP to backup egress
through switching the top label with the backup LSP label. The using the primary LSP label from the primary egress as an inner
backup egress delivers the packets to the same destinations as the label. The backup egress delivers the packets to the same
primary egress (see details in section "Considering Application destinations as the primary egress using the backup LSP label as
Traffic" below). context label and the inner label as UA label.
3.2.3. Signaling for S2L Sub LSP Protection 5.2.3. Signaling for S2L Sub LSP Protection
The S2L Sub LSP Protection is used to protect a primary egress of a The S2L Sub LSP Protection is used to protect a primary egress of a
P2MP LSP. Its major advantage is that the application traffic P2MP LSP. Its major advantage is that the application traffic
carried by the P2MP LSP may be easily protected against the egress carried by the LSP is easily protected against the egress failure.
failure.
The PLR determines to protect a primary egress of a P2MP LSP via S2L The PLR determines to protect a primary egress of a P2MP LSP via S2L
sub LSP protection when it receives a Path message with an EB-SERO sub LSP protection when it receives a Path message with flag "S2L Sub
object following the EGRESS_BACKUP_SUB_LSP containing the primary LSP Backup Desired" set.
egress and a backup egress.
The PLR sets up the backup S2L sub LSP to the backup egress, creates The PLR sets up the backup S2L sub LSP to the backup egress, creates
and maintains its state in the same way as of setting up a source to and maintains its state in the same way as of setting up a source to
leaf (S2L) sub LSP defined in RFC 4875 from the signaling's point of leaf (S2L) sub LSP defined in RFC 4875 from the signaling's point of
view. It constructs and sends a PATH message along the path given in view. It computes a path for the backup LSP from itself to the
the EB-SERO for the backup LSP, receives and processes a RESV message backup egress, constructs and sends a Path message along the path,
that responses to the PATH message. receives and processes a Resv message responding to the Path message.
After receiving the RESV message for the backup LSP, the PLR creates After receiving the Resv message for the backup LSP, the PLR creates
a forwarding entry with an inactive state or flag called inactive a forwarding entry with an inactive state or flag called inactive
forwarding entry. This inactive forwarding entry is not used to forwarding entry. This inactive forwarding entry is not used to
forward any data traffic during normal operations. forward any data traffic during normal operations.
When the PLR detects a failure in the primary egress failure, it When the PLR detects the failure of the primary egress, it changes
changes the forwarding entry for the backup LSP to active. Thus, the the forwarding entry for the backup LSP to active. Thus, the PLR
PLR forwards the traffic to the backup egress through the backup LSP, forwards the traffic to the backup egress through the backup LSP,
which sends the traffic to its destination. which sends the traffic to its destination.
3.2.4. PLR Procedures during Local Repair 5.2.4. PLR Procedures during Local Repair
When the upstream node of a primary egress of an LSP as a PLR detects When the upstream node of a primary egress of an LSP as a PLR detects
a failure in the primary egress, it follows the procedures defined in the failure of the primary egress, it follows the procedures defined
section 6.5 of RFC 4090. in section 6.5 of RFC 4090. It SHOULD notify the ingress about the
failure of the primary egress in the same way as a PLR notifies the
The PLR (i.e., the upstream node of the primary egress) SHOULD notify ingress about the failure of an intermediate node.
the ingress about the failure of the primary egress in the same way
as a PLR notifies the ingress about the failure of an intermediate
node.
In the local revertive mode, the PLR re-signals each of the primary In the local revertive mode, the PLR re-signals each of the primary
LSPs that used to be routed over the restored resource once it LSPs that were routed over the restored resource once it detects that
detects that the resource is restored. Every primary LSP the resource is restored. Every primary LSP successfully re-signaled
successfully re-signaled along the restored resource is switched along the restored resource is switched back.
back.
Moreover, the PLR lets the upstream part of the primary LSP stay Moreover, the PLR lets the upstream part of the primary LSP stay
after the primary egress fails. The downstream part of the primary after the primary egress fails. The downstream part of the primary
LSP from the PLR to the primary egress SHOULD be removed. LSP from the PLR to the primary egress SHOULD be removed.
4. Considering Application Traffic 6. Considering Application Traffic
This section focuses on the application traffic carried by P2P LSPs. This section focuses on the application traffic carried by P2P LSPs.
When a primary egress of a P2MP LSP fails, the application traffic When a primary egress of a P2MP LSP fails, the application traffic
carried by the P2MP LSP may be delivered to the same destination by carried by the P2MP LSP may be delivered to the same destination by
the backup egress since the inner label if any for the traffic is a the backup egress since the inner label if any for the traffic is a
upstream assigned label for every egress of the P2MP LSP. upstream assigned label for every egress of the P2MP LSP.
4.1. A Typical Application 6.1. A Typical Application
L3VPN is a typical application that an LSP carries. An existing L3VPN is a typical application. An existing solution (refer to
solution (refer to Figure 2) for protecting L3VPN traffic against Figure 2) for protecting L3VPN traffic against egress failure
egress failure includes: 1) A multi-hop BFD session between ingress includes: 1) A multi-hop BFD session between ingress R1 and egress L1
R1 and egress L1 of primary LSP; 2) A backup LSP from ingress R1 to of primary LSP; 2) A backup LSP from ingress R1 to backup egress La;
backup egress La; 3) La sends R1 VPN backup label and related 3) La sends R1 VPN backup label and related information via BGP; 4)
information via BGP; 4) R1 has a VRF with two sets of routes: one R1 has a VRF with two sets of routes: one uses primary LSP and L1 as
uses primary LSP and L1 as next hop; the other uses backup LSP and La next hop; the other uses backup LSP and La as next hop.
as next hop.
CE1,CE2 in [R2]*****[R3]*****[L1] **** Primary LSP CE1,CE2 in [R2]*****[R3]*****[L1] **** Primary LSP
one VPN * : $ ---- Backup LSP one VPN * : $ ---- Backup LSP
* .................: $ .... BFD Session * .................: $ .... BFD Session
[R1] ..: [CE2] $ Link [R1] ..: [CE2] $ Link
$ \ $ $ $ \ $ $
$ \ $ $ \ $
[CE1] [R4]-----[R5]-----[La](BGP sends R1 VPN backup label) [CE1] [R4]-----[R5]-----[La](BGP sends R1 VPN backup label)
Figure 2: Protect Egress for L3VPN Traffic Figure 2: Protect Egress for L3VPN Traffic
In normal operations, R1 sends the traffic from CE1 through primary In normal operations, R1 sends the traffic from CE1 through primary
LSP with VPN label received from L1 as inner label to L1, which LSP with VPN label received from L1 as inner label to L1, which
delivers the traffic to CE2 using VPN label. delivers the traffic to CE2 using VPN label.
When R1 detects a failure in L1, R1 sends the traffic from CE1 via When R1 detects the failure of L1, R1 sends the traffic from CE1 via
backup LSP with VPN bakup label received from La as inner label to backup LSP with VPN backup label received from La as inner label to
La, which delivers the traffic to CE2 using VPN backup label. La, which delivers the traffic to CE2 using VPN backup label.
A new solution (refer to Figure 3) with egress local protection for A new solution (refer to Figure 3) with egress local protection for
protecting L3VPN traffic includes: 1) A BFD session between R3 and protecting L3VPN traffic includes: 1) A BFD session between R3 and
egress L1 of primary LSP; 2) A backup LSP from R3 to backup egress egress L1 of primary LSP; 2) A backup LSP from R3 to backup egress
La; 3) L1 sends La VPN label as UA label and related information via La; 3) L1 sends La VPN label as UA label and related information; 4)
BGP or another protocol; 4) L1 and La is virtualized as one from R1's L1 and La is virtualized as one. This can be achieved by configuring
point of view. a same local address on L1 and La, using the address as a destination
of the LSP and BGP next hop for VPN traffic.
CE1,CE2 in [R2]*****[R3]*****[L1] **** Primary LSP CE1,CE2 in [R2]*****[R3]*****[L1] **** Primary LSP
one VPN * \ :.....: $ ---- Backup LSP one VPN * \ :.....: $ ---- Backup LSP
* \ $ .... BFD Session * \ $ .... BFD Session
[R1] \ [CE2] $ Link [R1] \ [CE2] $ Link
$ \ $ $ $ \ $ $
$ \ $ $ \ $
[CE1] [La](VPN label from L1 as UA label) [CE1] [La](VPN label from L1 as UA label)
Figure 3: Locally Protect Egress for L3VPN Traffic Figure 3: Locally Protect Egress for L3VPN Traffic
When R3 detects a failure in L1, R3 sends the traffic from primary When R3 detects L1's failure, R3 sends the traffic from primary LSP
LSP via backup LSP to La, which delivers the traffic to CE2 using VPN via backup LSP to La, which delivers the traffic to CE2 using VPN
label under the backup LSP label as a context label. label as UA label under the backup LSP label as a context label.
4.2. PLR Procedure for Applications 6.2. PLR Procedure for Applications
When the PLR creates a backup LSP from itself to a backup egress for When the PLR gets a backup LSP from itself to a backup egress for
protecting a primary egress, it includes an EGRESS_BACKUP_SUB_LSP protecting a primary egress of a primary LSP, it includes an
object in the Path message for the LSP. The object contains the EGRESS_BACKUP object in the Path message for the primary LSP. The
primary egress and the backup egress and indicates that the backup object contains the ID information of the backup LSP and indicates
egress SHOULD consider the backup LSP label as a context label and that the primary egress SHOULD send the backup egress the application
the inner label as application traffic label when needed. traffic label (e.g., VPN label) as UA label when needed.
4.3. Egress Procedures for Applications 6.3. Egress Procedures for Applications
When a primary egress of an LSP sends the ingress of the LSP a label When a primary egress of an LSP sends the ingress of the LSP a label
for an application such as a VPN, it SHOULD sends the backup egress for an application such as a VPN, it SHOULD send the backup egress
for protecting the primary egress the label as a upstream assigned for protecting the primary egress the label as a UA label via BGP or
label via BGP or another protocol. Exactly how the label is sent is another protocol. Exactly how the label is sent is out of scope for
out of scope for this document. this document.
When the backup egress receives a upstream assigned label from the
primary egress, it adds a forwarding entry with the label into the
LFIB for the primary egress. Using this entry, the backup egress
delivers the traffic with this label as inner label from the backup
LSP to the same destination as the primary egress.
When the backup egress receives a packet from the backup LSP, it uses When the backup egress receives a UA label from the primary egress,
the top label as a context label to find the LFIB for the primary it adds a forwarding entry with the label into the LFIB for the
egress and the inner label to deliver the packet to the same primary egress. When the backup egress receives a packet from the
destination as the primary egress according to the LFIB. backup LSP, it uses the top label as a context label to find the LFIB
for the primary egress and the inner label to deliver the packet to
the same destination as the primary egress according to the LFIB.
5. 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.
6. IANA Considerations 8. IANA Considerations
TBD IANA considerations for new objects will be specified after the
objects used are decided upon.
7. Contributors 9. Contributors
Boris Zhang Boris Zhang
Telus Communications Telus Communications
200 Consilium Pl Floor 15 200 Consilium Pl Floor 15
Toronto, ON M1H 3J3 Toronto, ON M1H 3J3
Canada Canada
Email: Boris.Zhang@telus.com Email: Boris.Zhang@telus.com
Zhenbin Li Zhenbin Li
Huawei Technologies Huawei Technologies
Huawei Bld., No.156 Beiqing Rd. Huawei Bld., No.156 Beiqing Rd.
Beijing 100095 Beijing 100095
China China
Email: lizhenbin@huawei.com Email: lizhenbin@huawei.com
Nan Meng
Huawei Technologies
Huawei Bld., No.156 Beiqing Rd.
Beijing 100095
China
Email: mengnan@huawei.com
Vic Liu Vic Liu
China Mobile China Mobile
No.32 Xuanwumen West Street, Xicheng District No.32 Xuanwumen West Street, Xicheng District
Beijing, 100053 Beijing, 100053
China China
Email: liuzhiheng@chinamobile.com
8. Acknowledgement 10. Acknowledgement
The authors would like to thank Richard Li, Tarek Saad, Lizhong Jin, The authors would like to thank Richard Li, Tarek Saad, Lizhong Jin,
Ravi Torvi, Eric Gray, Olufemi Komolafe, Michael Yue, Rob Rennison, Ravi Torvi, Eric Gray, Olufemi Komolafe, Michael Yue, Rob Rennison,
Neil Harrison, Kannan Sampath, Yimin Shen, Ronhazli Adam and Quintin Neil Harrison, Kannan Sampath, Yimin Shen, Ronhazli Adam and Quintin
Zhao for their valuable comments and suggestions on this draft. Zhao for their valuable comments and suggestions on this draft.
9. References 11. References
9.1. Normative References 11.1. 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, March 1997.
[RFC3692] Narten, T., "Assigning Experimental and Testing Numbers [RFC3692] Narten, T., "Assigning Experimental and Testing Numbers
Considered Useful", BCP 82, RFC 3692, January 2004. Considered Useful", BCP 82, RFC 3692, January 2004.
[RFC2205] Braden, B., Zhang, L., Berson, S., Herzog, S., and S. [RFC2205] Braden, B., Zhang, L., Berson, S., Herzog, S., and S.
Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
Functional Specification", RFC 2205, September 1997. Functional Specification", RFC 2205, September 1997.
skipping to change at page 13, line 43 skipping to change at page 14, line 5
[RFC4875] Aggarwal, R., Papadimitriou, D., and S. Yasukawa, [RFC4875] Aggarwal, R., Papadimitriou, D., and S. Yasukawa,
"Extensions to Resource Reservation Protocol - Traffic "Extensions to Resource Reservation Protocol - Traffic
Engineering (RSVP-TE) for Point-to-Multipoint TE Label Engineering (RSVP-TE) for Point-to-Multipoint TE Label
Switched Paths (LSPs)", RFC 4875, May 2007. Switched Paths (LSPs)", RFC 4875, May 2007.
[RFC5331] Aggarwal, R., Rekhter, Y., and E. Rosen, "MPLS Upstream [RFC5331] Aggarwal, R., Rekhter, Y., and E. Rosen, "MPLS Upstream
Label Assignment and Context-Specific Label Space", Label Assignment and Context-Specific Label Space",
RFC 5331, August 2008. RFC 5331, August 2008.
[RFC5786] Aggarwal, R. and K. Kompella, "Advertising a Router's
Local Addresses in OSPF Traffic Engineering (TE)
Extensions", RFC 5786, March 2010.
[P2MP FRR] [P2MP FRR]
Le Roux, J., Aggarwal, R., Vasseur, J., and M. Vigoureux, Le Roux, J., Aggarwal, R., Vasseur, J., and M. Vigoureux,
"P2MP MPLS-TE Fast Reroute with P2MP Bypass Tunnels", "P2MP MPLS-TE Fast Reroute with P2MP Bypass Tunnels",
draft-leroux-mpls-p2mp-te-bypass , March 1997. draft-leroux-mpls-p2mp-te-bypass , March 1997.
9.2. Informative References 11.2. Informative References
[RFC4461] Yasukawa, S., "Signaling Requirements for Point-to- [RFC4461] Yasukawa, S., "Signaling Requirements for Point-to-
Multipoint Traffic-Engineered MPLS Label Switched Paths Multipoint Traffic-Engineered MPLS Label Switched Paths
(LSPs)", RFC 4461, April 2006. (LSPs)", RFC 4461, April 2006.
Authors' Addresses Authors' Addresses
Huaimo Chen Huaimo Chen
Huawei Technologies Huawei Technologies
Boston, MA Boston, MA
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