One document matched: draft-zhao-mpls-mldp-protections-01.txt
Differences from draft-zhao-mpls-mldp-protections-00.txt
Network Working Group Q. Zhao
Internet-Draft E. Chen
Intended status: Standards Track Huawei Technology
Expires: May 26, 2012 November 23, 2011
Protection Mechanisms for Label Distribution Protocol P2MP/MP2MP Label
Switched Paths
draft-zhao-mpls-mldp-protections-01.txt
Abstract
Service providers continue to deploy real-time multicast applications
using Multicast LDP (mLDP) across MPLS networks. There is a clear
need to protect these real-time applications and to provide the
shortest switching times in the event of failure. This document
outlines the requirements, describes the protection mechanisms
available, and where necessary proposes extensions to facilitate mLDP
P2MP and MP2MP LSP protection within an MPLS network.
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
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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."
This Internet-Draft will expire on May 26, 2012.
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Table of Contents
1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Requirement Language . . . . . . . . . . . . . . . . . . . . . 4
3. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Requirements . . . . . . . . . . . . . . . . . . . . . . . 6
3.2. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. mLDP Local Protection using P2P LSP . . . . . . . . . . . . . 6
4.1. Signaling procedures for P2P Based Local Protection . . . 8
4.2. Protocol Extensions for P2P Based Local Protection . . . . 8
5. mLDP Local Protection using P2MP LSP . . . . . . . . . . . . . 9
5.1. Signaling Procedures for P2MP Based Local Protection . . . 11
5.2. Protocol extensions for P2MP Based Local Protection . . . 12
6. mLDP End-to-End Protection using LDP/mLDP Multiple Topology . 13
6.1. Signaling Procedures for MT Based End-to-end Protection . 16
6.2. Protocol extensions for MT Based End-to-end Protection . . 16
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
8. Manageability Considerations . . . . . . . . . . . . . . . . . 16
8.1. Control of Function and Policy . . . . . . . . . . . . . . 16
8.2. Information and Data Models . . . . . . . . . . . . . . . 16
8.3. Liveness Detection and Monitoring . . . . . . . . . . . . 16
8.4. Verifying Correct Operation . . . . . . . . . . . . . . . 16
8.5. Requirements on Other Protocols and Functional
Component . . . . . . . . . . . . . . . . . . . . . . . . 16
8.6. Impact on Network Operation . . . . . . . . . . . . . . . 16
8.7. Policy Control . . . . . . . . . . . . . . . . . . . . . . 16
9. Security Considerations . . . . . . . . . . . . . . . . . . . 17
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 17
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17
11.1. Normative References . . . . . . . . . . . . . . . . . . . 17
11.2. Informative References . . . . . . . . . . . . . . . . . . 18
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Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18
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1. Terminology
For a clear narrative, this section gives a general conceptional
overview of the terms.
o PLR: The node where the traffic is logically redirected onto the
preset backup path is called Point of Local Repair.
o MP: The node where the backup path merges with the primary path is
called Merge Point.
o FD: The node that detects the failure on primary path, and then
triggers the action(s) for traffic protection is called Failure
Detector. Either traffic sender or receiver can be the FD,
depending on which protection mode are deployed. More details are
described in later sections of this document.
o SP: The node where the traffic is physically switched/duplicated
onto the backup path is called Switchover Point. In multicast
cases, PLR and SP can be two different nodes. More details are
described in later sections of this document.
2. Requirement Language
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 [RFC2119].
3. Introduction
In order to meet user demands, operators and service providers
continue to deploy multicast applications using mLDP across MPLS
networks. In certain scenarios, traditional IGP-mLDP convergence
mechanisms fail to meet protection switching times required to
minimise, or negate entirely, application interruptions for real-time
applications, including stock trading, on-line games, and multimedia
teleconferencing.
Current best practice for protecting services, and higher
applications includes the pre-computation and establishment of a
backup path, this can decrease the convergence time efficiently.
Once a failure has been detected on the primary path, the traffic
should be transmitted across the back-up path.
However, two major challenges exist with the aforementioned solution.
The first is how to build an absolutely disjointed backup path for
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each node in a multicast tree; the second is how to balance between
convergence time and resource consumption.
This document provides several ways to setup the backup path for mLDP
LSP, including P2P tunnel based mLDP local protection, P2MP LSP based
mLDP local protection, and end-to-end protection. The goal is to
build a reliable umbrella to against traffic black hole. Note that
the buackup path computation is out of the scope of this draft, the
algorothm can be either LFA or any other algorithms available
including the offline tools. Besides, how to detect failure is also
outside the scope of this document.
More and more users are apt to deploy multicast applications on MPLS
mLDP network. In some scenarios, traditional IGP-mLDP convergence is
hard to meet the requirements of those real-time applications, such
as stock business, on-line game, and multimedia teleconference.
The industry has reached a consensus that setting up a backup path
previously can decrease the convergence time efficiently. No matter
how the above-mentioned backup path was established, once the failure
is detected, the traffic should be transmitted at that path as soon
as possible. Even so, there are still two major challenges left for
us, one is how to build an absolutely disjointed backup path for each
node in a multicast tree; the other is how to balance between
convergence time and resource consumption.
It is getting urgent to find the ideal protection mechanism(s) to
improve the convergence time, and at the meantime minimize the side-
effects, such as bandwidth wastage.
For a primary LDP P2MP/MP2MP LSP, there are several ways to set up
its backup path. It can use RSVP-TE P2P tunnel as a logical out-
going interface, consequently utilize the mature high availability
technologies of RSVP-TE. Or, it can make use of LDP P2P backup LSP
as a packet encapsulation, so that the complex configuration of P2P
RSVP-TE can be skipped. Or, it can build its own P2MP/MP2MP backup
LSP according to IGP's loop-free alternative route, thus avoid
unnecessary packet duplication. Other than these, it can also build
a totally disjointed LSP in another topology, accordingly take
advantage of the real end-to-end protection.
When the backup path is present, there are two options for packet
forwarding and switchover. If the traffic sender feeds the stream on
both paths, and the traffic receiver drops packet on backup path, the
switchover will be very quick once the failure is detected, because
the whole switchover action is a local behavior on traffic receiver.
The disadvantage of this manner is that traffic will be duplicated on
both paths, and consume double bandwidth. Contrastively, if the
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traffic sender feeds stream only on the primary path, the resource
wastage can be waived. Cooperation is needed in this manner, so
there will be some protocol extensions. But if the performance can
be equal or better than the previous option, it is reasonable to
choose the second one.
This document describes several methods to setup and switch paths for
options to setup the backup LDP P2MP/MP2MP LSP. mLDP LSPs, including
local protection, territorial protection, and end-to-end protection.
The goal is to identify strengths, weaknesses and gaps, in order to
build a reliable set of tools to shield against traffic black holes
that would severely impact real-time applications, in the event of
primary path failure.
3.1. Requirements
A number of requirements have been identified that allow the optimal
set of mechanisms to developed. These currently include:
o Computation of a disjointed (link and node) backup path within the
multicast tree;
o Minimisation of protection convergence time;
o Optimisation of bandwidth usage.
3.2. Scope
The method to detect failure is outside the scope of this document.
Also this document does not provide any authorization mechanism for
controlling the set of LSRs that may attempt to join a mLDP
protection session.
4. mLDP Local Protection using P2P LSP
By encapsulating mLDP packets within an P2P TE tunnel or P2P LDP
backup LSP, the LDP P2MP/MP2MP LSP can be protected by the P2P
protection mechanisms. However, this protection mechanism is not
capable of detecting, and recovering, if the failure occurs on the
destination node of the P2P backup LSP. Thus, this section provides
a unified method to protect both node and link with P2P backup LSP.
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+------------+ Point of Local Repair/
| R1 | Switchover Point
+------------+ (Upstream LSR)
/ \
/ \
10/ \20
/ \
/ \
/ \
+----------+ +-----------+
| R2 | | R3 |
+----------+ +-----------+
| \ |
| \ |
| \ |
10| 10\ 20|
| \ |
| \ |
| \ |
| \ |
| \ |
| \ |
+-----------+ 10 +-----------+ Merge Point
| R4 |------| R5 | (Downstream LSR)
+-----------+ +-----------+
mLDP Local Protection using P2P LSP
Figure 1
In Figure 1 (P2P Based mLDP Local Protection Example) above, the
preferential path from R1 to R4/R5 is through R2, and the secondary
path is through R3. In this case, the mLDP LSP will be established
according to the IGP preferential path as R1--R2--R4/R5.
It is the responsibility of R2 to inform R1 of its downstream LSRs
(in this example R4 and R5) and the respective labels (L4 and L5).
Once the link between R1 and R2 fails, or R2 node fails, R1 will
duplicate the traffic to R4 and R5, with inner label as L4/L5, and
outer label as the P2P backup LSP R1--R3--R5--R4 and R1--R3--R5.
Finally, the previous forwarding states will be removed after R4 and
R5 finish their Make-Before-Break (MBB) procedure.
Note that the mLDP Local Protection mechanism can be used in any part
of the mLDP LSP other then the ingress and egress nodes. In other
words, R1 can be either Ingress or Transit node, R4/R5 can be either
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Transit or Egress node. Only R1 and R2 need enhancement for this
mechanism, other nodes can just follow the existing mature protocol
procedures.
4.1. Signaling procedures for P2P Based Local Protection
Continuing to use Figure 1 (mLDP Local Protection Example), R2 sends
a notification message to R1 to inform the node that R2 has two
downstream nodes, R4 and R5 with forwarding labels L4 and L5
respectively.
When R1 sees R2 node going down, it takes mLDP packets as it would
send them to R4 and R5 through R2 and sends them into the two P2P
backup tunnels:
o P2P tunnel R1--R3--R5--R4, using inner label L4.
o P2P tunnel R1--R3--R5, using inner label L5.
So that R4/R5 will receive same packets as from the interface between
R2 and R4/R5, just from different interface.
4.2. Protocol Extensions for P2P Based Local Protection
A new type of LDP MP Status Value Element is introduced, for
notifying downstream LSRs and respective labels. It is encoded as
follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|mLDP P2P Type=2| Length | Status Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Downstream Element 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Downstream Element N |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Status Code: 1 = Advertise the existing downstream LSRs
2 = Withdraw the deleted downstream LSRs
Encapsulation Status Code of mLDP Local Protection using P2P LSP
Figure 2
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The Downstream Element is encoded as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Downstream Label | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Downstream Node Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Downstream Element in mLDP P2P Encapsulation Status Code
Figure 3
5. mLDP Local Protection using P2MP LSP
Making use of IGP-FRR results, LDP can build the backup mLDP LSP
among PLR, the protected node, and MPs (the downstream nodes of the
protected node). In the cases where the amount of downstream nodes
are huge, this mechanism can avoid unnecessary packet duplication on
PLR, so that protect the network from traffic congestion risk.
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+------------+ Point of Local Repair/
| R1 | Switchover Point
+------------+ (Upstream LSR)
/ \
/ \
10/ \20
/ \
/ \
/ \
+----------+ +-----------+
Protected Node | R2 | | R3 |
+----------+ +-----------+
| \ / |
| \ / |
| \ / |
10| 10\ /20 20|
| \ / |
| \ |
| / \ |
| / \ |
| / \ |
| / \ |
+-----------+ +-----------+ Merge Point
| R4 | | R5 | (Downstream LSR)
+-----------+ +-----------+
mLDP Local Protection using P2MP LSP Example
Figure 4
In Figure 4 (P2MP Based mLDP Local Protection Example), the
preferential path from R1 to R4/R5 is through R2, and the secondary
path is through R3. In this case, the mLDP LSP will be established
according to the IGP preferential path as R1--R2--R4/R5. This
section will take the Protected Node as R2 for example, actually the
Protected Node can be any Transit node of the mLDP LSP.
As the Protected Node, R2 will announce its selected upstream node R1
to all its downstream nodes, which are R4 and R5 in this example. So
that R4 and R5 can consider R1 as the root node of the backup mLDP
LSP, and trigger the backup LSP signaling. At the mean time, R4/R5
will bind the backup ILM entry to the primary NHLFE(s), so that the
traffic receiving from backup mLDP LSP can be merged locally to the
primary LSP.
The primary LSP and backup LSP are differentiated by the signaling
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procedure, so normally PLR can only feed traffic only on the primary
path. When the link between R1 and R2 fails, or R2 node fails, R1
will switch the traffic to the preset backup path quickly.
In this scenario, if R2 is protected by two P2P LSPs as R1--R3--R4
and R1--R3--R5, the traffic will be duplicated on R1, and R3 will
receive two streams. If R2 is protected by mLDP LSP instead, R3 will
only receive one stream, and the packet duplication will be done on
R3.
5.1. Signaling Procedures for P2MP Based Local Protection
When the Protected Node (R2) determines its upstream LSR (R1), it
will notify to all its downstream nodes immediately. If there are
other LSR(s) becoming its downstream node(s) later, it will do the
announcement for the new downstream node(s).
When the Merge Point (R4/R5) receive the notification, they
individually determine the primary and secondary paths according to
the IGP-FRR results. Then they will send out label mapping messages
including an LDP MP Status TLV that carries a FRR Status Code to
indicate the primary path and secondary path. The backup path is
uniquely identified by root address, opaque value, PLR Node address,
and Protected Node address.
When the transit nodes of the secondary LSP receive the FRR label
mapping message, they can easily consider it as a new mLDP LSP
establishment, and follow the existing protocol procedures. The only
modification for these nodes is dealing with the FRR FEC, which is
identified by root address, opaque value, PLR address, and Protected
Node address.
When the Point of Local Repair (R1) receive the FRR label mapping
message, it will generate the backup forwarding entry for the
specific LSP, which is identified by the root address and opaque
value in the message, and bind and backup forwarding state to the
specific primary entry, which is indicated by the Protected Node
address in the message. Note that there might be more than one
backup forwarding entries for a specific protected node.
To avoid the backup LSP going through the Protected Node, additional
path selection rule(s) can be applied, such as not-via policy. This
part is under study, and will be added in the future.
When failure is detected by PLR, it will switch the traffic to the
secondary path. At the mean time, MP will locally merge the traffic
back to the primary LSP.
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When Merge Point(s) see the next hop to Root changed, it/they will
advertise the new mapping, and the traffic will re-converge to the
new primary path.
5.2. Protocol extensions for P2MP Based Local Protection
A new type of LDP MP Status Value Element is introduced, for
notifying upstream LSR. It is encoded as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|mLDP FRR Type=3| Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ PLR Node Address ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
P2MP Based mLDP Local Protection Status Code1
Figure 5
Besides, another new type of LDP MP Status Value Element is
introduced, for setting up secondary mLDP LSP. It is encoded as
follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|mLDP FRR Type=4| Length | Status code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ PLR Node Address ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Protected Node Address ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
P2MP Based mLDP Local Protection Status Code2
Figure 6
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mLDP FRR Type: Type 4 (to be assigned by IANA)
Length: If the Address Family is IPv4, the Address Length MUST be 4;
if the Address Family is IPv6, the Address Length MUST be 16.
Status code: 1 = Primary path for traffic forwarding
2 = Secondary path for traffic forwarding
PLR Node Address: The host address of the PLR Node.
Protected Node Address: The host address of the Protected Node.
P2MP Based mLDP Local Protection Status Code Parameters
Figure 7
6. mLDP End-to-End Protection using LDP/mLDP Multiple Topology
[I-D.ietf-mpls-ldp-multi-topology] also provides the mechanism to
setup disjointed LSPs within different topologies. So that
applications can use these redundant LSPs for end-to-end protection.
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+------------+ Point of Local Repair/
| Root | Switchover Point
+------------+
/ *
/ *
/ *
/ *
/ *
/ *
+----------+ +-----------+
| R1 | | R2 |
+----------+ +-----------+
| \ * *
| \ * *
| \ * *
| \ * *
| - - - * * * * *
| * \ *
| * \ *
| * \ *
| * \ *
| * \ *
+-----------+ +-----------+
| Leaf 1 | | Leaf 2 |
+-----------+ +-----------+
mLDP End-to-end Protection Example
Figure 8
In Figure 8 (mLDP End-to-end Protection Example), there are two
separated topologies from Root node to Leaf 1 and Leaf 2. For the
same root address and opaque value, the Leaf node can trigger mLDP
LSPs in each topology. Root node can setup 1:1 or 1+1 end-to-end
protection, using these two mLDP LSPs.
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+------------+ Point of Local Repair/
| Root | Switchover Point
+------------+
|
|
+------------+
| R1 | the upstream node shared by R2 and R3
+------------+
/ *
/ *
/ *
/ *
/ *
/ *
+----------+ +-----------+
| R2 | | R3 |
+----------+ +-----------+
| \ * *
| \ * *
| \ * *
| \ * *
| - - - * * * * *
| * \ *
| * \ *
| * \ *
| * \ *
| * \ *
+-----------+ +-----------+
| Leaf 1 | | Leaf 2 |
+-----------+ +-----------+
mLDP End-to-end Protection with Shared Upstream Node
Figure 9
In Figure 9 (mLDP End-to-end Protection with Shared Upstream Node
Example), there are two separated topologies from Root node to Leaf 1
and Leaf 2 except the link between R1 and Root node. For the same
root address and opaque value, the Leaf node can trigger mLDP LSPs in
each topology. Root node can setup 1:1 or 1+1 end-to-end protection,
using these two mLDP LSPs. The differece in this example comparing
to the last example where the priamry and backup topology are
totatlly disjoint, if there is a link failure between the Root and R1
or node R1 fails, there is no protection available.
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6.1. Signaling Procedures for MT Based End-to-end Protection
Using the signaling procedure provied by [I-D.ietf-mpls-ldp-multi-
topology], Leaf 1 and Leaf 2 are able to trigger mLDP LSPs in
different topologies, sending label mapping messages with same root
address, same opaque value, different MT-ID and different label.
When the Root node receives the label mapping messages from different
topologies, it will set up two mLDP LSPs for application as end-to-
end protection. Failure detection for the primary mLDP LSP is
outside the scope of this document. Either Root node or Leaf node
can be the Failure Detector.
6.2. Protocol extensions for MT Based End-to-end Protection
The protocol extensions required to build mLDP LSPs in different
topologies are defined in [I-D.ietf-mpls-ldp-multi-topology].
7. IANA Considerations
This memo includes the following requests to IANA:
o mLDP P2P Encapsulation type for LDP MP Status Value Element.
o mLDP FRR types for LDP MP Status Value Element.
8. Manageability Considerations
[Editors Note - This section requires further discussion]
8.1. Control of Function and Policy
8.2. Information and Data Models
8.3. Liveness Detection and Monitoring
8.4. Verifying Correct Operation
8.5. Requirements on Other Protocols and Functional Component
8.6. Impact on Network Operation
8.7. Policy Control
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9. Security Considerations
The same security considerations apply as for the base LDP
specification, as described in [RFC5036]. The protocol extensions
specified in this document do not provide any authorization mechanism
for controlling the set of LSRs that may attempt to join a mLDP
protection session. If such authorization is desirable, additional
mechanisms, outside the scope of this document, are needed.
Note that authorization policies should be implemented and/or
configure at all the nodes involved .
10. Acknowledgements
We would like to thank authors of draft-ietf-mpls-mp-ldp-reqs and the
authors of draft-ietf-mpls-ldp-multi-topology from which some text of
this document has been inspired. We also would like to thank Robin
Li, Tao Zhou and Lujun Wan for their comments and suggestions to the
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.
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
Label Switching Architecture", RFC 3031, January 2001.
[RFC5036] Andersson, L., Minei, I., and B. Thomas, "LDP
Specification", RFC 5036, October 2007.
[RFC5561] Thomas, B., Raza, K., Aggarwal, S., Aggarwal, R., and JL.
Le Roux, "LDP Capabilities", RFC 5561, July 2009.
[RFC6348] Le Roux, JL. and T. Morin, "Requirements for Point-to-
Multipoint Extensions to the Label Distribution Protocol",
RFC 6348, September 2011.
[RFC6388] Wijnands, IJ., Minei, I., Kompella, K., and B. Thomas,
"Label Distribution Protocol Extensions for Point-to-
Multipoint and Multipoint-to-Multipoint Label Switched
Paths", RFC 6388, November 2011.
[I-D.ietf-mpls-ldp-multi-topology]
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Zhao, Q., Fang, L., Zhou, C., Li, L., So, N., and R.
Torvi, "LDP Extensions for Multi Topology Routing",
draft-ietf-mpls-ldp-multi-topology-02 (work in progress),
November 2011.
11.2. Informative References
[RFC3468] Andersson, L. and G. Swallow, "The Multiprotocol Label
Switching (MPLS) Working Group decision on MPLS signaling
protocols", RFC 3468, February 2003.
Authors' Addresses
Quintin Zhao
Huawei Technology
125 Nagog Technology Park
Acton, MA 01719
US
Email: quintin.zhao@huawei.com
Emily Chen
Huawei Technology
2330 Central Expressway
Santa Clara, CA 95050
US
Email: emily.chenying@huawei.com
Zhao & Chen Expires May 26, 2012 [Page 18]
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