Extensions to RSVP-TE for LSP Egress Local Protection
draft-ietf-teas-rsvp-egress-protection-00
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft that was ultimately published as RFC 8400.
|
|
|---|---|---|---|
| Authors | Huaimo Chen , Zhenbin Li , Ning So , Autumn Liu , Tarek Saad , Fengman Xu , Mehmet Toy , Lu Huang , Lei Liu | ||
| Last updated | 2014-12-31 (Latest revision 2014-12-29) | ||
| Replaces | draft-ietf-mpls-rsvp-egress-protection | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Formats | |||
| Reviews |
GENART Telechat review
(of
-14)
Ready with Nits
SECDIR Last Call review
(of
-09)
Has Issues
GENART Last Call review
(of
-09)
On the Right Track
|
||
| Stream | WG state | WG Document | |
| Document shepherd | (None) | ||
| IESG | IESG state | I-D Exists | |
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-ietf-teas-rsvp-egress-protection-00
Internet Engineering Task Force H. Chen
Internet-Draft Z. Li
Intended status: Standards Track Huawei Technologies
Expires: July 2, 2015 N. So
Tata Communications
A. Liu
Ericsson
T. Saad
Cisco Systems
F. Xu
Verizon
M. Toy
Comcast
L. Huang
China Mobile
L. Liu
UC Davis
December 29, 2014
Extensions to RSVP-TE for LSP Egress Local Protection
draft-ietf-teas-rsvp-egress-protection-00.txt
Abstract
This document describes extensions to Resource Reservation Protocol -
Traffic Engineering (RSVP-TE) for locally protecting egress nodes of
a Traffic Engineered (TE) Label Switched Path (LSP) in a Multi-
Protocol Label Switching (MPLS) and Generalized MPLS (GMPLS) network.
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on July 2, 2015.
Copyright Notice
Chen, et al. Expires July 2, 2015 [Page 1]
Internet-Draft RSVP LSP Egress Protection December 2014
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. An Example of Egress Local Protection . . . . . . . . . . 3
1.2. Egress Local Protection with FRR . . . . . . . . . . . . . 4
2. Conventions Used in This Document . . . . . . . . . . . . . . 4
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Protocol Extensions . . . . . . . . . . . . . . . . . . . . . 4
4.1. EGRESS_BACKUP Object . . . . . . . . . . . . . . . . . . . 4
4.2. Flags in FAST_REROUTE . . . . . . . . . . . . . . . . . . 6
4.3. Path Message . . . . . . . . . . . . . . . . . . . . . . . 6
5. Egress Protection Behaviors . . . . . . . . . . . . . . . . . 6
5.1. Ingress Behavior . . . . . . . . . . . . . . . . . . . . . 7
5.2. Transit Node and PLR Behavior . . . . . . . . . . . . . . 7
5.2.1. Signaling for One-to-One Protection . . . . . . . . . 8
5.2.2. Signaling for Facility Protection . . . . . . . . . . 8
5.2.3. Signaling for S2L Sub LSP Protection . . . . . . . . . 9
5.2.4. PLR Procedures during Local Repair . . . . . . . . . . 10
6. Considering Application Traffic . . . . . . . . . . . . . . . 10
6.1. A Typical Application . . . . . . . . . . . . . . . . . . 10
6.2. PLR Procedure for Applications . . . . . . . . . . . . . . 11
6.3. Egress Procedures for Applications . . . . . . . . . . . . 12
7. Security Considerations . . . . . . . . . . . . . . . . . . . 12
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
8.1. New RSVP C-Num and C-Types . . . . . . . . . . . . . . . . 12
8.2. New TLVs . . . . . . . . . . . . . . . . . . . . . . . . . 12
8.3. Flags in FAST_REROUTE . . . . . . . . . . . . . . . . . . 13
9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 13
10. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 13
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
11.1. Normative References . . . . . . . . . . . . . . . . . . . 13
11.2. Informative References . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15
Chen, et al. Expires July 2, 2015 [Page 2]
Internet-Draft RSVP LSP Egress Protection December 2014
1. Introduction
RFC 4090 describes two methods for protecting the transit nodes of a
P2P LSP: one-to-one and facility protection. RFC 4875 specifies how
to use them to protect the transit nodes of a P2MP LSP. However,
they do not mention any local protection for an egress of an LSP.
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
LSP) to the backup egresses, where each egress is paired with a
backup egress and protected by the backup egress.
This approach may use more resources and provide slow fault recovery.
This document specifies extensions to RSVP-TE for local protection of
an egress of an LSP, which overcomes these disadvantages.
1.1. An Example of Egress Local Protection
Figure 1 shows an example of using backup LSPs to locally protect
egresses of a primary P2MP LSP from ingress R1 to two egresses: L1
and L2. The primary LSP is represented by star(*) lines and backup
LSPs by hyphen(-) lines.
La and Lb are the designated backup egresses for egresses L1 and L2
respectively. To distinguish an egress (e.g., L1) from a backup
egress (e.g., La), an egress is called a primary egress if needed.
The backup LSP for protecting L1 is from its upstream node R3 to
backup egress La. The one for protecting L2 is from R5 to Lb.
[R2]*****[R3]*****[L1]
* \ :.....: $ **** Primary LSP
* \ $ ---- Backup LSP
* \ [CE1] .... BFD Session
* \ $ $ Link
* \ $ $
* [La] $
*
[R1]******[R4]*******[R5]*****[L2]
$ \ :.....: $
$ \ $
[S] \ [CE2]
\ $
\ $
[Lb]
Figure 1: Backup LSP for Locally Protecting Egress
Chen, et al. Expires July 2, 2015 [Page 3]
Internet-Draft RSVP LSP Egress Protection December 2014
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
Using the egress local protection and the FRR, we can locally protect
the egresses, the links and the transit nodes of an LSP. The traffic
switchover time is within tens of milliseconds whenever an egress,
any of the links and the transit nodes of the LSP fails.
The egress nodes of the LSP can be locally protected via the egress
local protection. All the links and the transit nodes of the LSP can
be locally protected through using the FRR.
2. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119.
3. Terminology
This document uses terminologies defined in RFC 2205, RFC 3031, RFC
3209, RFC 3473, RFC 4090, RFC 4461, and RFC 4875.
4. Protocol Extensions
A new object EGRESS_BACKUP is defined for egress local protection.
It contains a backup egress for a primary egress.
4.1. EGRESS_BACKUP Object
The class of the EGRESS_BACKUP object is TBD-1 to be assigned by
IANA. The C-Type of the EGRESS_BACKUP IPv4/IPv6 object is TBD-2/
TBD-3 to be assigned by IANA.
Chen, et al. Expires July 2, 2015 [Page 4]
Internet-Draft RSVP LSP Egress Protection December 2014
EGRESS_BACKUP Class Num = TBD-1, IPv4/IPv6 C-Type = TBD-2/TBD-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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Backup Egress IPv4/IPv6 address ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Primary Egress IPv4/IPv6 address ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ (Subobjects) ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Backup Egress IPv4/IPv6 address:
IPv4/IPv6 address of the backup egress node
o Primary Egress IPv4/IPv6 address:
IPv4/IPv6 address of the primary egress node
The Subobjects are TLVs and 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.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ P2P LSP Tunnel Egress IPv4/IPv6 Address (4/16 bytes) ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Tunnel ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Extended Tunnel ID (4/16 bytes) ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o P2P LSP Tunnel Egress IPv4/IPv6 Address:
IPv4/IPv6 address of the egress of the tunnel
o Tunnel ID:
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
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ (sub-TLVs ) ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Chen, et al. Expires July 2, 2015 [Page 5]
Internet-Draft RSVP LSP Egress Protection December 2014
The sub-TLVs are optional.
4.2. Flags in FAST_REROUTE
Two new bits of the flags in the FAST_REROUTE object may be defined.
One bit (called "S2L Sub LSP Backup Desired" flag) indicates whether
S2L Sub LSP is desired for protecting an egress of a P2MP LSP. When
a S2L Sub LSP is desired for protecting an egress of a P2MP LSP, we
should set this flag to one.
The other bit (called "Other Sending UA Label" flag) indicates if
another protocol is desired for sending a label as a UA label from a
primary egress to a backup egress. When we want other protocol such
as BGP to send a label as UA label, this flag should be set to one.
4.3. Path Message
A Path message is enhanced to carry the information about a backup
egress for a primary egress of an LSP by including an egress backup
descriptor list. The format of the message is illustrated below.
<Path Message> ::= <Common Header> [ <INTEGRITY> ]
[ [<MESSAGE_ID_ACK> | <MESSAGE_ID_NACK>] ...]
[ <MESSAGE_ID> ]<SESSION> <RSVP_HOP> <TIME_VALUES>
[ <EXPLICIT_ROUTE> ]
<LABEL_REQUEST> [ <PROTECTION> ] [ <LABEL_SET> ...]
[ <SESSION_ATTRIBUTE> ] [ <NOTIFY_REQUEST> ]
[ <ADMIN_STATUS> ] [ <POLICY_DATA> ... ]
<sender descriptor> [<S2L sub-LSP descriptor list>]
[<egress backup descriptor list>]
The egress backup descriptor list in the message is defined below.
It is a sequence of EGRESS_BACKUP objects, each of which describes a
pair of a primary egress and a backup egress.
<egress backup descriptor list> ::=
<egress backup descriptor>
[ <egress backup descriptor list> ]
<egress backup descriptor> ::= <EGRESS_BACKUP>
5. Egress Protection Behaviors
Chen, et al. Expires July 2, 2015 [Page 6]
Internet-Draft RSVP LSP Egress Protection December 2014
5.1. Ingress Behavior
To protect a primary egress of an LSP, the ingress MUST set the
"label recording desired" flag and the "node protection desired" flag
in the SESSION_ATTRIBUTE object.
If one-to-one backup or facility backup method is desired to protect
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
Desired" flag.
If S2L Sub LSP backup method is desired to protect a primary egress
of a P2MP LSP, the ingress SHOULD include a FAST_REROUTE object and
set the "S2L Sub LSP Backup Desired" flag.
If another protocol is desired for sending a label as a upstream
assigned label to a backup egress, the ingress SHOULD set the "Other
Sending UA Label" 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. Transit Node and PLR Behavior
If a transit node of an LSP receives the Path message with an egress
backup descriptor list and it is not an upstream node of any primary
egress of the LSP, it forwards the list unchanged.
If the transit node is the upstream node of a primary egress to be
protected, it determines the backup egress, obtains a path for the
backup LSP and sets up the backup LSP along the path.
The PLR (upstream node of the primary egress) extracts the backup
egress from the respective EGRESS_BACKUP object in the egress backup
descriptor list. If no matching EGRESS_BACKUP object is found or the
list is empty, the PLR may apply a local policy to determine the
backup egress and add an EGRESS_BACKUP object with the backup egress
and primary egress into a Path message to the primary egress.
After obtaining the backup egress, the PLR tries to compute a backup
path from itself to the backup egress. It excludes the primary
Chen, et al. Expires July 2, 2015 [Page 7]
Internet-Draft RSVP LSP Egress Protection December 2014
egress to be protected when computing the path. Thus the PLR will
not select any path via the primary 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" 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
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
backup LSP from itself to a backup egress.
If the LSP is a P2MP LSP and a primary egress of the LSP is also a
transit node (i.e., bud node), the upstream node of the primary
egress as a PLR also creates a backup LSP from itself to each of the
next hops of the primary egress.
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
backup egress. For the failure of the bud node of a P2MP LSP, the
PLR MUST also switch the packets to the backup LSPs to the bud node's
next hops, where the packets are merged into the primary LSP.
5.2.2. Signaling for Facility Protection
Except for backup LSP and downstream label, the behavior of the
upstream node of the primary egress of a primary LSP as a PLR follows
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
same primary egress, the primary egress of these LSPs may be
protected by one backup LSP from the PLR to the backup egress
designated for protecting the primary egress.
The PLR selects or creates a backup LSP from itself to the backup
egress. If there is a backup LSP that satisfies the constraints
given in the Path message, then this one is selected; otherwise, a
Chen, et al. Expires July 2, 2015 [Page 8]
Internet-Draft RSVP LSP Egress Protection December 2014
new backup LSP to the backup egress will be created.
After getting the backup LSP, the PLR associates the backup LSP with
a primary LSP for protecting its primary egress. The PLR records
that the backup LSP is used to protect the primary LSP against its
primary egress failure and includes an EGRESS_BACKUP object in the
Path message to the primary egress. The object contains the backup
egress and the backup LSP ID. It indicates that the primary egress
SHOULD send the backup egress the service label as UA label if there
is a service carried by the LSP and the primary LSP label as UA label
if the label is not implicit null.
A UA label can be sent via RSVP or another protocol (e.g., BGP). If
"Other Sending UA Label" flag is one, the primary egress SHOULD send
the UA labels to the backup egress through another protocol;
otherwise, UA labels are sent via RSVP.
After receiving the Path message with the EGRESS_BACKUP, the primary
egress includes the information about the UA labels in the Resv
message with an EGRESS_BACKUP object. When the PLR receives the Resv
message with the information about the UA labels, it includes the
information in the Path message for the backup LSP to the backup
egress. Thus the UA labels are sent to the backup egress from the
primary egress via RSVP.
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
and keeps the primary LSP label from the primary egress in the label
stack if the label is not implicit null. The backup egress delivers
the packets to the same destinations as the primary egress using the
backup LSP label as context label and the labels under as UA labels.
5.2.3. Signaling for S2L Sub LSP Protection
The S2L Sub LSP Protection is used to protect a primary egress of a
P2MP LSP. Its major advantage is that the application traffic
carried by the LSP is easily protected against the egress failure.
The PLR determines to protect a primary egress of a P2MP LSP via S2L
sub LSP protection when it receives a Path message with flag "S2L Sub
LSP Backup Desired" set.
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
leaf (S2L) sub LSP defined in RFC 4875 from the signaling's point of
view. It computes a path for the backup LSP from itself to the
backup egress, constructs and sends a Path message along the path,
receives and processes a Resv message responding to the Path message.
Chen, et al. Expires July 2, 2015 [Page 9]
Internet-Draft RSVP LSP Egress Protection December 2014
After receiving the Resv message for the backup LSP, the PLR creates
a forwarding entry with an inactive state or flag called inactive
forwarding entry. This inactive forwarding entry is not used to
forward any data traffic during normal operations.
When the PLR detects the failure of the primary egress, it changes
the forwarding entry for the backup LSP to active. Thus, the PLR
forwards the traffic to the backup egress through the backup LSP,
which sends the traffic to its destination.
5.2.4. PLR Procedures during Local Repair
When the upstream node of a primary egress of an LSP as a PLR detects
the failure of the primary egress, it follows the procedures defined
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
ingress about the failure of a transit node.
Moreover, the PLR lets the upstream part of the primary LSP stay
after the primary egress fails. It continues to send Resv message to
its upstream node along the primary LSP. The downstream part of the
primary LSP from the PLR to the primary egress SHOULD be removed.
In the local revertive mode, the PLR re-signals each of the primary
LSPs that were routed over the restored resource once it detects that
the resource is restored. Every primary LSP successfully re-signaled
along the restored resource is switched back.
6. Considering Application Traffic
This section focuses on the application traffic carried by P2P LSPs.
When a primary egress of a P2MP LSP fails, the application traffic
carried by the P2MP LSP is delivered to the same destination by the
backup egress since the inner label if any for the traffic is a
upstream assigned label for every egress of the P2MP LSP.
6.1. A Typical Application
L3VPN is a typical application. An existing solution (refer to
Figure 2) for protecting L3VPN traffic against egress failure
includes: 1) A multi-hop BFD session between ingress R1 and egress L1
of primary LSP; 2) A backup LSP from ingress R1 to backup egress La;
3) La sends R1 VPN backup label and related information via BGP; 4)
R1 has a VRF with two sets of routes: one uses primary LSP and L1 as
next hop; the other uses backup LSP and La as next hop.
Chen, et al. Expires July 2, 2015 [Page 10]
Internet-Draft RSVP LSP Egress Protection December 2014
CE1,CE2 in [R2]*****[R3]*****[L1] **** Primary LSP
one VPN * : $ ---- Backup LSP
* .................: $ .... BFD Session
[R1] ..: [CE2] $ Link
$ \ $ $
$ \ $
[CE1] [R4]-----[R5]-----[La](BGP sends R1 VPN backup label)
Figure 2: Protect Egress for L3VPN Traffic
In normal operations, R1 sends the traffic from CE1 through primary
LSP with VPN label received from L1 as inner label to L1, which
delivers the traffic to CE2 using VPN label.
When R1 detects the failure of L1, R1 sends the traffic from CE1 via
backup LSP with VPN backup label received from La as inner label to
La, which delivers the traffic to CE2 using VPN backup label.
A new solution (refer to Figure 3) with egress local protection for
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
La; 3) L1 sends La VPN label as UA label and related information; 4)
L1 and La is virtualized as one. This can be achieved by configuring
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
one VPN * \ :.....: $ ---- Backup LSP
* \ $ .... BFD Session
[R1] \ [CE2] $ Link
$ \ $ $
$ \ $
[CE1] [La](VPN label from L1 as UA label)
Figure 3: Locally Protect Egress for L3VPN Traffic
When R3 detects L1's failure, R3 sends the traffic from primary LSP
via backup LSP to La, which delivers the traffic to CE2 using VPN
label as UA label under the backup LSP label as a context label.
6.2. PLR Procedure for Applications
When the PLR gets a backup LSP from itself to a backup egress for
protecting a primary egress of a primary LSP, it includes an
EGRESS_BACKUP object in the Path message for the primary LSP. The
object contains the ID information of the backup LSP and indicates
Chen, et al. Expires July 2, 2015 [Page 11]
Internet-Draft RSVP LSP Egress Protection December 2014
that the primary egress SHOULD send the backup egress the application
traffic label (e.g., VPN label) as UA label when needed.
6.3. Egress Procedures for Applications
When a primary egress of an LSP sends the ingress of the LSP a label
for an application such as a VPN, it SHOULD send the backup egress
for protecting the primary egress the label as a UA label. Exactly
how the label is sent is out of scope for this document.
When the backup egress receives a UA label from the primary egress,
it adds a forwarding entry with the label into the LFIB for the
primary egress. When the backup egress receives a packet from the
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.
7. Security Considerations
In principle this document does not introduce new security issues.
The security considerations pertaining to RFC 4090, RFC 4875 and
other RSVP protocols remain relevant.
8. IANA Considerations
8.1. New RSVP C-Num and C-Types
This document defines a new C-Num, which should be assigned by IANA.
o EGRESS_BACKUP object. The C-Num should be of the form 11bbbbbb so
that LSRs that do not recognize it will ignore it but forward it.
Two C-Types defined for this object should be assigned by IANA.
- EGRESS_BACKUP_IPv4. Recommended C-Type value 1.
- EGRESS_BACKUP_IPv6. Recommended C-Type value 2.
8.2. New TLVs
The new object referenced above contains TLVs. This document defines
three TLV types as follows:
Type Name Allowed on
1 P2P_LSP_ID_IPv4 TLV EGRESS_BACKUP_IPv4
2 P2P_LSP_ID_IPv6 TLV EGRESS_BACKUP_IPv6
3 Label TLV EGRESS_BACKUP_IPv4/IPv6
Chen, et al. Expires July 2, 2015 [Page 12]
Internet-Draft RSVP LSP Egress Protection December 2014
8.3. Flags in FAST_REROUTE
Two flags defined in FAST_REROUTE object should be assigned by IANA.
0x04 S2L Sub LSP Backup Desired
0x08 Other Sending UA Label
9. Contributors
Boris Zhang
Telus Communications
200 Consilium Pl Floor 15
Toronto, ON M1H 3J3
Canada
Email: Boris.Zhang@telus.com
Nan Meng
Huawei Technologies
Huawei Bld., No.156 Beiqing Rd.
Beijing 100095
China
Email: mengnan@huawei.com
Vic Liu
China Mobile
No.32 Xuanwumen West Street, Xicheng District
Beijing, 100053
China
Email: liuzhiheng@chinamobile.com
10. Acknowledgement
The authors would like to thank Richard Li, Nobo Akiya, Jeffrey
Zhang, Lizhong Jin, Ravi Torvi, Eric Gray, Olufemi Komolafe, Michael
Yue, Daniel King, Rob Rennison, Neil Harrison, Kannan Sampath, Yimin
Shen, Ronhazli Adam and Quintin Zhao for their valuable comments and
suggestions on this draft.
11. References
11.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
Chen, et al. Expires July 2, 2015 [Page 13]
Internet-Draft RSVP LSP Egress Protection December 2014
[RFC3692] Narten, T., "Assigning Experimental and Testing Numbers
Considered Useful", BCP 82, RFC 3692, January 2004.
[RFC2205] Braden, B., Zhang, L., Berson, S., Herzog, S., and S.
Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
Functional Specification", RFC 2205, September 1997.
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
Label Switching Architecture", RFC 3031, January 2001.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, December 2001.
[RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching
(GMPLS) Signaling Resource ReserVation Protocol-Traffic
Engineering (RSVP-TE) Extensions", RFC 3473, January 2003.
[RFC4090] Pan, P., Swallow, G., and A. Atlas, "Fast Reroute
Extensions to RSVP-TE for LSP Tunnels", RFC 4090,
May 2005.
[RFC4875] Aggarwal, R., Papadimitriou, D., and S. Yasukawa,
"Extensions to Resource Reservation Protocol - Traffic
Engineering (RSVP-TE) for Point-to-Multipoint TE Label
Switched Paths (LSPs)", RFC 4875, May 2007.
[RFC5331] Aggarwal, R., Rekhter, Y., and E. Rosen, "MPLS Upstream
Label Assignment and Context-Specific Label Space",
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]
Le Roux, J., Aggarwal, R., Vasseur, J., and M. Vigoureux,
"P2MP MPLS-TE Fast Reroute with P2MP Bypass Tunnels",
draft-leroux-mpls-p2mp-te-bypass , March 1997.
11.2. Informative References
[RFC4461] Yasukawa, S., "Signaling Requirements for Point-to-
Multipoint Traffic-Engineered MPLS Label Switched Paths
(LSPs)", RFC 4461, April 2006.
Chen, et al. Expires July 2, 2015 [Page 14]
Internet-Draft RSVP LSP Egress Protection December 2014
Authors' Addresses
Huaimo Chen
Huawei Technologies
Boston, MA
USA
Email: huaimo.chen@huawei.com
Zhenbin Li
Huawei Technologies
Huawei Bld., No.156 Beiqing Rd.
Beijing 100095,
China
Email: lizhenbin@huawei.com
Ning So
Tata Communications
2613 Fairbourne Cir.
Plano, TX 75082
USA
Email: ningso01@gmail.com
Autumn Liu
Ericsson
CA
USA
Email: autumn.liu@ericsson.com
Tarek Saad
Cisco Systems
Email: tsaad@cisco.com
Chen, et al. Expires July 2, 2015 [Page 15]
Internet-Draft RSVP LSP Egress Protection December 2014
Fengman Xu
Verizon
2400 N. Glenville Dr
Richardson, TX 75082
USA
Email: fengman.xu@verizon.com
Mehmet Toy
Comcast
1800 Bishops Gate Blvd.
Mount Laurel, NJ 08054
USA
Email: mehmet_toy@cable.comcast.com
Lu Huang
China Mobile
No.32 Xuanwumen West Street, Xicheng District
Beijing, 100053
China
Email: huanglu@chinamobile.com
Lei Liu
UC Davis
USA
Email: liulei.kddi@gmail.com
Chen, et al. Expires July 2, 2015 [Page 16]