Internet DRAFT - draft-ietf-mpls-p2mp-loose-path-reopt
draft-ietf-mpls-p2mp-loose-path-reopt
MPLS Working Group Tarek Saad, Ed.
Internet-Draft Rakesh Gandhi, Ed.
Intended status: Standards Track Zafar Ali
Expires: April 3, 2015 Cisco Systems, Inc.
Robert H. Venator
Defense Information Systems Agency
Yuji Kamite
NTT Communications Corporation
September 30, 2014
Extensions to Resource Reservation Protocol For Re-optimization
of Loosely Routed Point-to-Multipoint Traffic Engineering LSPs
draft-ietf-mpls-p2mp-loose-path-reopt-01
Abstract
For a Traffic Engineered (TE) point-to-multipoint (P2MP) Label
Switched Path (LSP), it is preferable in some cases to re-evaluate
and re-optimize the entire P2MP-TE LSP by re-signaling all its
Source-to-Leaf (S2L) sub-LSP(s). Existing mechanisms, a mechanism
for an ingress Label Switched Router (LSR) to trigger a new path re-
evaluation request and a mechanism for a mid-point LSR to notify an
availability of a preferred path, operate on an individual or a sub-
group of S2L sub-LSP(s) basis only.
This document defines RSVP-TE signaling extensions to allow an
ingress node of a P2MP-TE LSP to request the re-evaluation of the
entire LSP tree containing one or more S2L sub-LSPs whose paths are
loose (or abstract) hop expanded, and for a mid-point LSR to notify
to the ingress node that a preferable tree exists for the entire
P2MP-TE LSP. This document also defines markers to indicate
beginning and end of a S2L sub-LSP descriptor list when RSVP message
needs to be fragmented due to large number of S2L sub-LSPs when
performing re-optimization.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
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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."
Copyright Notice
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.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Existing Mechanism For Re-optimizing Loosely Routed
P2MP-TE LSP . . . . . . . . . . . . . . . . . . . . . . . 4
1.2. Combining Multiple Path Messages for Re-optimization . . . 5
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 7
2.2. Nomenclatures . . . . . . . . . . . . . . . . . . . . . . 7
2.3. Conventions Used in This Document . . . . . . . . . . . . 7
3. Signaling Procedure For Loosely Routed P2MP-TE LSP
Re-optimization . . . . . . . . . . . . . . . . . . . . . . . 8
3.1. Tree Based Re-optimization . . . . . . . . . . . . . . . . 8
3.2. Sub-group Based Re-optimization . . . . . . . . . . . . . 8
4. RSVP Signaling Extensions . . . . . . . . . . . . . . . . . . 9
4.1. P2MP-TE Tree Re-evaluation Request Flag . . . . . . . . . 9
4.2. Preferable P2MP-TE Tree Exists Path Error Sub-code . . . . 10
4.3. Markers For S2L sub-LSP Descriptor . . . . . . . . . . . . 10
5. Compatibility . . . . . . . . . . . . . . . . . . . . . . . . 11
6. Security Considerations . . . . . . . . . . . . . . . . . . . 11
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
7.1. P2MP-TE Tree Re-evaluation Request Flag . . . . . . . . . 12
7.2. Preferable P2MP-TE Tree Exists Path Error Sub-code . . . . 12
7.3. BEGIN and END Markers For S2L sub-LSP Descriptor . . . . . 12
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
9.1. Normative References . . . . . . . . . . . . . . . . . . . 14
9.2. Informative References . . . . . . . . . . . . . . . . . . 14
Author's Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15
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1. Introduction
This document defines Resource Reservation Protocol - Traffic
Engineering (RSVP-TE) [RFC2205] [RFC3209] signaling extensions for
re-optimizing loosely routed Point-to-Multipoint (P2MP) Traffic
Engineered (TE) Label Switched Paths (LSPs) [RFC4875] in an
Multi-Protocol Label Switching (MPLS) and/or Generalized MPLS (GMPLS)
networks.
A P2MP-TE LSP is comprised of one or more source-to-leaf (S2L)
sub-LSPs. A loosely routed P2MP-TE S2L sub-LSP is defined as one
whose path does not contain the full explicit route identifying each
node along the path to the egress node at the time of its signaling
by the ingress node. Such an S2L sub-LSP is signaled with no
Explicit Route Object (ERO) [RFC3209], or with an ERO that contains
at least one loose hop, or with an ERO that contains an abstract node
that is not a simple abstract node (that is, an abstract node that
identifies more than one node). This is often the case with
inter-domain P2MP-TE LSPs where Path Computation Element (PCE) is not
used [RFC5440].
As per [RFC4875], an ingress node may re-optimize the entire P2MP-TE
LSP by re-signaling all its S2L sub-LSP(s) or may re-optimize
individual or group of S2L sub-LSP(s) i.e. individual or group of
destination(s).
1.1. Existing Mechanism For Re-optimizing Loosely Routed P2MP-TE LSP
[RFC4736] defines RSVP signaling extensions for re-optimizing loosely
routed P2P TE LSP(s) as follows.
- A mid-point LSR that expands loose next-hop(s) sends a solicited or
unsolicited PathErr with the Notify error code (25 as defined in
[RFC3209]) with sub-code 6 to indicate "Preferable Path Exists" to
the ingress node.
- An ingress node triggers a path re-evaluation request at all
mid-point LSR(s) that expands loose next-hop(s) by setting the "Path
Re-evaluation Request" flag (0x20) in SESSION_ATTRIBUTES Object in
the Path message.
- The ingress node upon receiving this PathErr either solicited or
unsolicited initiates re-optimization of the LSP.
[RFC4736] does not define signaling extensions specific for
re-optimizing entire P2MP-TE LSP tree. Mechanisms defined in
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[RFC4736] can be used for signaling the re-optimization of individual
or group of S2L sub-LSP(s). However, to use [RFC4736] mechanisms for
re-optimizing an entire P2MP-TE LSP tree, an ingress node needs to
send the path re-evaluation requests on all (typically 100s of) S2L
sub-LSPs and the mid-point LSR to notify PathErrs for all S2L
sub-LSPs. Such a procedure may lead to the following issues:
- A mid-point LSR that expands loose next-hop(s) may have to
accumulate the received path re-evaluation request(s) for all S2L
sub-LSPs (e.g, by using a wait timer) and interpret them as a
re-optimization request for the whole P2MP-TE LSP tree. Otherwise, a
mid-point LSR may prematurely notify "Preferable Path Exists" for one
or a sub-set of S2L sub-LSPs.
- The ingress node that receives (un)solicited PathErr
notification(s) for individual S2L sub-LSP(s), may prematurely start
re-optimizing the sub-set of S2L sub-LSPs. However, as mentioned in
[RFC4875] Section 14.2, such sub-group based re-optimization
procedure may result in data duplication that can be avoided if the
entire P2MP-TE LSP tree is re-optimized using a different LSP-ID,
especially if the ingress node eventually receives PathErr
notifications for all S2L sub-LSPs of the P2MP-TE LSP tree.
- The ingress node may have to heuristically determine when to
perform entire P2MP-TE LSP tree re-optimization versus per S2L sub-
LSP re-optimization, for example, to delay re-optimization long
enough to allow all PathErr(s) to be received. Once all PathErr(s)
are received, the ingress node has to accumulate them to see if re-
optimization of the entire P2MP-TE is necessary. Such procedures may
produce undesired results due to timing related issues. This may be
easily avoided by the RSVP signaling messages defined in this
document.
1.2. Combining Multiple Path Messages for Re-optimization
Based on [RFC4875] (Section 14.2 "Sub-Group-Based Re-Optimization"),
an ingress node may trigger path re-evaluation requests for a set of
S2L sub-LSPs by combining multiple Path messages using S2L sub-LSP
descriptor list. A mid-point LSR may send a PathErr message
containing a list of S2L sub-LSPs transiting through the LSR to
notify the ingress node. This method can alleviate the scale issue
associated with sending RSVP messages for individual S2L sub-LSPs.
This method is useful for re-optimizing a sub-group of S2L sub-LSPs
within an LSP tree. However, this procedure can lead to following
issues:
- Path message that is intended to carry the path re-evaluation
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request as defined in [RFC4736] with a full list of S2L sub-LSPs in
S2L sub-LSPs descriptor list will be decomposed at branching LSRs,
and only a subset of the S2L sub-LSPs that are routed over the same
next-hop will be added in the descriptor list of the Path message
propagated to downstream mid-point LSRs. Consequently, when a
preferable path exists at such mid-point LSRs, the PathErr can only
include the sub-set of S2L sub-LSPs traversing the LSR. In this
case, at the ingress node there is no way to distinguish which mode
of re-optimization to invoke, i.e. sub-group based re-optimization
using the same LSP-ID or tree based re-optimization using a different
LSP-ID.
- An LSR may fragment a large RSVP message (when a combined message
may not be large enough to fit all S2L sub-LSPs). In this case, the
ingress node may receive multiple PathErrs with sub-sets of S2L
sub-LSPs in each (either due to the combined Path message got
fragmented or combined PathErr message got fragmented) and would
require additional logic to infer to re-optimize the tree (for
example, waiting for some time to aggregate all possible PathErr
messages before taking an action).
As discussed in Section 1.1 and Section 1.2 of this document, there
is a requirement to align re-optimization of P2MP-TE LSP with P2P LSP
[RFC4736] to have a mechanism to trigger re-optimization of the LSP
tree by re-signaling all S2L sub-LSPs with a different LSP-ID. There
is also a need to define markers to indicate beginning and end of the
S2L sub-LSP descriptor list when an RSVP message is fragmented due to
large number of S2L sub-LSPs in the message.
This document defines RSVP-TE signaling extensions for the ingress
node of a P2MP-TE LSP to trigger the re-evaluation of the P2MP LSP
tree on every hop that has a next hop defined as a loose or abstract
hop for one or more S2L sub-LSP path, and a mid-point LSR to signal
to the ingress node that a preferable LSP tree exists (compared to
the current path) or that the whole P2MP-TE LSP must be re-optimized
(because of maintenance required on the TE LSP path). This document
also defines markers to indicate beginning and end of a S2L sub-LSP
descriptor list when RSVP message needs to be fragmented due to large
number of S2L sub-LSPs when performing re-optimization.
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2. Terminology
2.1. Abbreviations
ABR: Area Border Router.
AS: Autonomous System.
ERO: Explicit Route Object.
LSR: Label Switching Router.
TE LSP: Traffic Engineering Label Switched Path.
TE LSP ingress: Head-end/source of the TE LSP.
TE LSP egress: Tail-end/destination of the TE LSP.
2.2. Nomenclatures
Domain: Routing or administrative domain such as an IGP area and an
autonomous system.
Interior Gateway Protocol Area (IGP Area): OSPF Area or IS-IS level.
Inter-area TE LSP: A TE LSP whose path transits across at least two
different IGP areas.
Inter-AS MPLS TE LSP: A TE LSP whose path transits across at least
two different Autonomous Systems (ASes) or sub-ASes (BGP
confederations).
S2L sub-LSP: Source-to-leaf sub Label Switched Path.
2.3. 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 [RFC2119]. The reader
is assumed to be familiar with the terminology in [RFC4875] and
[RFC4736].
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3. Signaling Procedure For Loosely Routed P2MP-TE LSP Re-optimization
3.1. Tree Based Re-optimization
To evaluate an entire P2MP-TE LSP tree on mid-point LSRs that expand
loose next-hop(s), an ingress node MAY send a Path message with
"P2MP-TE Tree Re-evaluation Request" defined in this document. An
ingress node SHOULD select one of the S2L sub-LSPs of the P2MP-TE LSP
tree transiting a mid-point LSR to trigger the re-evaluation request.
A mid-point LSR that expands loose next-hop(s) for one or more S2L
sub-LSP path(s), and that receives a Path message with the "P2MP-TE
Tree Re-evaluation Request" bit set, SHOULD check for a preferable
P2MP-TE LSP tree by re-evaluating all S2L sub-LSP(s) that are
expanded paths of the loose next-hops of the P2MP-TE LSP. If a
preferable P2MP-TE LSP tree is found, the mid-point LSR MAY send an
RSVP PathErr to the ingress node with Error code 25 (Notify defined
in [RFC3209] and Error sub-code defined in this document "Preferable
P2MP-TE Tree Exists". The mid-point LSR, in turn, SHOULD not
propagate the "P2MP-TE Tree Re-evaluation Request" bit in subsequent
RSVP Path messages sent downstream for the re-evaluated P2MP-TE LSP.
The sending of an RSVP PathErr Notify message "Preferable P2MP-TE
Tree Exists" to the ingress node SHALL notify the ingress node of the
existence of a preferable P2MP-TE LSP tree. In addition, a mid-point
LSR MAY send an unsolicited PathErr message with "Preferable P2MP-TE
Tree Exists" PathErr code 25 to the ingress node to notify of a
preferred the P2MP-TE LSP tree when it determines it exists. In this
case, the mid-point LSR that expands loose next-hop(s) for one or
more S2L sub-LSP path(s) SHOULD select one of the S2L sub-LSP(s) of
the P2MP-TE LSP tree to send this PathErr message to the ingress
node.
If no preferable tree for P2MP-TE LSP can be found, the recommended
mode is that the mid-point LSR that expands loose next-hop(s) for one
or more S2L sub-LSP path(s) SHOULD propagate the request downstream
by setting the "P2MP-TE Tree Re-evaluation Request" bit in the
LSP_ATTRIBUTES Object of RSVP Path message.
3.2. Sub-group Based Re-optimization
It might be preferable, as per [RFC4875], to re-optimize the entire
P2MP-TE LSP by re-signaling all of its S2L sub-LSP(s) (Section 14.1,
"Make-before-Break") or to re-optimize individual or group of S2L
sub-LSP(s) i.e. individual or group of destination(s) (Section 14.2
"Sub-Group-Based Re-Optimization" in [RFC4875]), both using the same
LSP-ID. For loosely routed S2L sub-LSPs, this can be achieved by
using the procedures defined in [RFC4736] to re-optimize one or more
S2L sub-LSP(s) of the P2MP-TE LSP.
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An ingress node may trigger path re-evaluation requests for a set of
S2L sub-LSPs by combining multiple Path messages using S2L sub-LSP
descriptor list [RFC4875]. An S2L sub-LSP descriptor list is created
using a series of S2L_SUB_LSP Objects as defined in [RFC4875].
Similarly, a mid-point LSR may send a PathErr message containing a
list of S2L sub-LSPs transiting through the LSR to notify the ingress
node of preferable paths available.
As per [RFC4875] (Section 5.2.3, "Transit Fragmentation of Path State
Information"), when a Path message is not large enough to fit all S2L
sub-LSPs in the descriptor list, an LSR may fragment the message. In
this case, the LSR MAY add S2L_SUB_LSP_MARKER_BEGIN and
S2L_SUB_LSP_MARKER_END Objects defined in this document at the
beginning and at the end of the S2L sub-LSP descriptor list,
respectively.
Both S2L_SUB_LSP_MARKER_BEGIN and S2L_SUB_LSP_MARKER_END Objects
defined in this document are optional. However, a node MUST add the
S2L_SUB_LSP_MARKER_END Object if it has added
S2L_SUB_LSP_MARKER_BEGIN Object in the S2L sub-LSP descriptor list.
A mid-point LSR SHOULD wait to accumulate all S2L sub-LSPs before
attempting to re-evaluate preferable path when a Path message for
"Path Re-evaluation Request" is received with
S2L_SUB_LSP_MARKER_BEGIN. An ingress node SHOULD wait to accumulate
all S2L sub-LSPs before attempting to trigger re-optimization when a
PathErr message with "Preferable Path Exists" is received with
S2L_SUB_LSP_MARKER_BEGIN.
New objects S2L_SUB_LSP_MARKER_BEGIN and S2L_SUB_LSP_MARKER_END
defined in this document have a wider applicability than the P2MP-TE
LSP re-optimization but it is outside the scope of this document.
4. RSVP Signaling Extensions
4.1. P2MP-TE Tree Re-evaluation Request Flag
In order to trigger a tree re-evaluation request, a new flag is
defined in Attributes Flags TLV of the LSP_ATTRIBUTES Object
[RFC5420] as follows:
Bit Number (to be assigned by IANA): P2MP-TE Tree Re-evaluation
Request flag
The "P2MP-TE Tree Re-evaluation Request" flag is meaningful in a Path
message of a P2MP-TE S2L sub-LSP and is inserted by the ingress node.
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4.2. Preferable P2MP-TE Tree Exists Path Error Sub-code
In order to indicate to an ingress node that a preferable P2MP-TE LSP
tree exists, the following new sub-code for PathErr code 25 (Notify
Error) [RFC3209] is defined:
Sub-code (to be assigned by IANA): Preferable P2MP-TE Tree Exists
sub-code
When a preferable path for P2MP-TE LSP tree exists, the mid-point LSR
sends a solicited or unsolicited "Preferable P2MP-TE Tree Exists"
PathErr notification to the ingress node of the P2MP-TE LSP.
4.3. Markers For S2L sub-LSP Descriptor
An S2L_SUB_LSP Object [RFC4875] identifies a particular S2L sub-LSP
belonging to the P2MP-TE LSP. An S2L sub-LSP descriptor list is
created using a series of S2L_SUB_LSP Objects as defined in
[RFC4875].
In order to indicate the beginning and end of the S2L sub-LSP
descriptor list when the RSVP message needs to be fragmented due to
large number of S2L sub-LSPs, the following new types are defined for
the S2L_SUB_LSP Object [RFC4875].
S2L_SUB_LSP_MARKER_BEGIN :
Class-Num 50, C-Type TBA by IANA
+-----------------+---------------+--------------------------+
| Length (4 bytes)| Class_Num 50 | S2L_SUB_LSP_MARKER_BEGIN |
+-----------------+---------------+--------------------------+
S2L_SUB_LSP_MARKER_END :
Class-Num 50, C-Type TBA by IANA
+-----------------+---------------+--------------------------+
| Length (4 bytes)| Class_Num 50 | S2L_SUB_LSP_MARKER_END |
+-----------------+---------------+--------------------------+
The S2L_SUB_LSP_MARKER_BEGIN Object is added before adding the first
S2L_SUB_LSP_IPv4 or S2L_SUB_LSP_IPv6 Object and the
S2L_SUB_LSP_MARKER_END Object is added after adding the last
S2L_SUB_LSP_IPv4 or S2L_SUB_LSP_IPv6 Object in the S2L sub-LSP
descriptor list.
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5. Compatibility
The LSP_ATTRIBUTES Object has been defined in [RFC5420] with class
numbers in the form 11bbbbbb, which ensures compatibility with
non-supporting nodes. Per [RFC2205], nodes not supporting this
extension will ignore the new flag defined in this document but
forward it without modification.
The S2L_SUB_LSP_MARKER_BEGIN and S2L_SUB_LSP_MARKER_END Objects have
been defined with class numbers in the form 11bbbbbb, which ensures
compatibility with non-supporting nodes. Per [RFC2205], nodes not
supporting new S2L_SUB_LSP_MARKER_BEGIN and S2L_SUB_LSP_MARKER_END
Objects will ignore them but forward it without modification.
6. Security Considerations
This document defines a mechanism for a mid-point LSR to notify the
ingress node of a P2MP-TE LSP of the existence of a preferable tree.
As per [RFC4736], in the case of a P2MP-TE LSP S2L sub-LSP spanning
multiple domains, it may be desirable for a mid-point LSR to modify
the RSVP PathErr message defined in this document to maintain
confidentiality across different domains. Furthermore, an ingress
node may decide to ignore this PathErr message coming from a
mid-point LSR residing in another domain. Similarly, an mid-point
LSR may decide to ignore the tree re-evaluation request originating
from another ingress domain.
7. IANA Considerations
IANA is requested to administer assignment of new values for
namespace defined in this document and summarized in this section.
IANA maintains a name space for RSVP-TE TE parameters "Resource
Reservation Protocol-Traffic Engineering (RSVP-TE) Parameters" (see
http://www.iana.org/assignments/rsvp-te-parameters/rsvp-te-
parameters.xml). From the registries in this name space "Attribute
Flags", allocation of new flag is requested (Section 4.1).
IANA also maintains a name space for RSVP protocol parameters
"Resource Reservation Protocol (RSVP) Parameters" (see
http://www.iana.org/assignments/rsvp-parameters/rsvp-parameters.xml).
From the sub-registry "Sub-Codes - 25 Notify Error" in registry
"Error Codes and Globally-Defined Error Value Sub-Codes", allocation
of a new error code is requested (Section 4.2). Also, from the
sub-registry "Class Types or C-Types 50 S2L_SUB_LSP" in registry
"Class Names, Class Numbers, and Class Types", allocation of new
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C-Types is requested (Section 4.3).
7.1. P2MP-TE Tree Re-evaluation Request Flag
The following new flag is defined for the Attributes Flags TLV in the
LSP_ATTRIBUTES Object [RFC5420]. The numeric value is to be assigned
by IANA.
o P2MP-TE Tree Re-evaluation Request Flag:
+--------+---------------+---------+---------+---------+------------+
| Bit No | Attribute | Carried | Carried | Carried | Reference |
| | Flag Name | in Path | in Resv | in RRO | |
+--------+---------------+---------+---------+---------+------------+
| TBA by | P2MP-TE Tree | Yes | No | No | This |
| IANA | Re-evaluation | | | | document |
+--------+---------------+---------+---------+---------+------------+
7.2. Preferable P2MP-TE Tree Exists Path Error Sub-code
As defined in [RFC3209], the Error Code 25 in the ERROR SPEC Object
corresponds to a Notify Error PathErr. This document adds a new
sub-code as follows for this PathErr:
o Preferable P2MP-TE Tree Exists sub-code:
+----------+--------------------+---------+---------+-----------+
| Sub-code | Sub-code | PathErr | PathErr | Reference |
| value | Description | Code | Name | |
+----------+--------------------+---------+---------+-----------+
| TBA by | Preferable P2MP-TE | 25 | Notify | This |
| IANA | Tree Exists | | Error | document |
+----------+--------------------+---------+---------+-----------+
7.3. BEGIN and END Markers For S2L sub-LSP Descriptor
As defined in [RFC4875], S2L_SUB_LSP Object is defined with
Class-Number 50 to identify a particular S2L sub-LSP belonging to the
P2MP-TE LSP. This document adds two new object types for this object
as follows:
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o S2L_SUB_LSP_MARKER_BEGIN and S2L_SUB_LSP_MARKER_END Object types:
+---------------+---------------------------+-----------------+
| C-Type value | Description | Reference |
+---------------+---------------------------+-----------------+
| TBA by IANA | S2L_SUB_LSP_MARKER_BEGIN | This document |
+---------------+---------------------------+-----------------+
| TBA by IANA | S2L_SUB_LSP_MARKER_END | This document |
+---------------+---------------------------+-----------------+
8. Acknowledgments
The authors would like to thank Loa Andersson, Sriganesh Kini, Curtis
Villamizar, Dimitri Papadimitriou and Nobo Akiya for reviewing this
document.
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9. References
9.1. Normative References
[RFC2205] Braden, R., Ed., Zhang, L., Berson, S., Herzog, S., and S.
Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
Functional Specification", RFC 2205, September 1997.
[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.
[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.
[RFC5420] Farrel, A., Papadimitriou, D., Vasseur, JP., and A.
Ayyangarps, "Encoding of Attributes for MPLS LSP
Establishment Using Resource Reservation Protocol Traffic
Engineering (RSVP-TE)", RFC 5420, February 2009.
9.2. Informative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4736] Vasseur, JP., Ikejiri, Y. and Zhang, R, "Reoptimization of
Multiprotocol Label Switching (MPLS) Traffic Engineering
(TE) Loosely Routed Label Switched Path (LSP)", RFC 4736,
November 2006.
[RFC5440] Vasseur, JP., Ed., and JL. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol (PCEP)", RFC 5440,
March 2009.
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Author's Addresses
Tarek Saad (editor)
Cisco Systems
Email: tsaad@cisco.com
Rakesh Gandhi (editor)
Cisco Systems
Email: rgandhi@cisco.com
Zafar Ali
Cisco Systems
Email: zali@cisco.com
Robert H. Venator
Defense Information Systems Agency
Email: robert.h.venator.civ@mail.mil
Yuji Kamite
NTT Communications Corporation
Email: y.kamite@ntt.com
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