draft-ietf-teas-gmpls-resource-sharing-proc-05.txt   draft-ietf-teas-gmpls-resource-sharing-proc-06.txt 
TEAS Working Group X. Zhang TEAS Working Group X. Zhang
Internet-Draft H. Zheng, Ed. Internet-Draft H. Zheng, Ed.
Intended Status: Informational Huawei Technologies Intended Status: Informational Huawei Technologies
Expires: February 17, 2017 R. Gandhi, Ed. Expires: June 11, 2017 R. Gandhi, Ed.
Z. Ali Z. Ali
Cisco Systems, Inc. Cisco Systems, Inc.
P. Brzozowski P. Brzozowski
ADVA Optical ADVA Optical
August 16, 2016 December 8, 2016
RSVP-TE Signaling Procedure for End-to-End GMPLS Restoration and RSVP-TE Signaling Procedure for End-to-End GMPLS Restoration and
Resource Sharing Resource Sharing
draft-ietf-teas-gmpls-resource-sharing-proc-05 draft-ietf-teas-gmpls-resource-sharing-proc-06
Abstract Abstract
In non-packet transport networks, there are requirements where In non-packet transport networks, there are requirements where
Generalized Multi-Protocol Label Switching (GMPLS) end-to-end Generalized Multi-Protocol Label Switching (GMPLS) end-to-end
recovery scheme needs to employ restoration Label Switched Path (LSP) recovery scheme needs to employ restoration Label Switched Path (LSP)
while keeping resources for the working and/or protecting LSPs while keeping resources for the working and/or protecting LSPs
reserved in the network after the failure occurs. reserved in the network after the failure occurs.
This document reviews how the LSP association is to be provided using This document reviews how the LSP association is to be provided using
skipping to change at page 3, line 20 skipping to change at page 3, line 20
Traffic Engineering (RSVP-TE) [RFC3473]. These protocols can be used Traffic Engineering (RSVP-TE) [RFC3473]. These protocols can be used
to setup Label Switched Paths (LSPs) in non-packet transport to setup Label Switched Paths (LSPs) in non-packet transport
networks. The GMPLS protocol extends MPLS to support interfaces networks. The GMPLS protocol extends MPLS to support interfaces
capable of Time Division Multiplexing (TDM), Lambda Switching and capable of Time Division Multiplexing (TDM), Lambda Switching and
Fiber Switching. These switching technologies provide several Fiber Switching. These switching technologies provide several
protection schemes [RFC4426][RFC4427] (e.g., 1+1, 1:N and M:N). protection schemes [RFC4426][RFC4427] (e.g., 1+1, 1:N and M:N).
Resource Reservation Protocol - Traffic Engineering (RSVP-TE) Resource Reservation Protocol - Traffic Engineering (RSVP-TE)
signaling has been extended to support various GMPLS recovery signaling has been extended to support various GMPLS recovery
schemes, such as end-to-end recovery [RFC4872] and segment recovery schemes, such as end-to-end recovery [RFC4872] and segment recovery
[RFC4873]. As described in [RFC6689], ASSOCIATION object can be used [RFC4873]. As described in [RFC6689], an ASSOCIATION object can be
to identify the LSPs for restoration using Association Type set to used to identify the LSPs for restoration using Association Type set
"Recovery" [RFC4872] and also identify the LSPs for resource sharing to "Recovery" [RFC4872] and also identify the LSPs for resource
using Association Type set to "Resource Sharing" [RFC4873]. sharing using Association Type set to "Resource Sharing" [RFC4873].
[RFC6689] Section 2.2 reviews the procedure for providing LSP [RFC6689] Section 2.2 reviews the procedure for providing LSP
associations for GMPLS end-to-end recovery and Section 2.4 reviews associations for GMPLS end-to-end recovery and Section 2.4 reviews
the procedure for providing LSP associations for sharing resources. the procedure for providing LSP associations for sharing resources.
In GMPLS end-to-end recovery schemes generally considered, Generally GMPLS end-to-end recovery schemes have the restoration LSP
restoration LSP is signaled after the failure has been detected and signaled after the failure has been detected and notified on the
notified on the working LSP. For revertive recovery mode, a working LSP. For revertive recovery mode, a restoration LSP is
restoration LSP is signaled while working LSP and/or protecting LSP signaled while working LSP and/or protecting LSP are not torn down in
are not torn down in control plane due to a failure. In non-packet control plane due to a failure. In non-packet transport networks, as
transport networks, as working LSPs are typically signaled over a working LSPs are typically signaled over a nominal path, service
nominal path, service providers would like to keep resources providers would like to keep resources associated with the working
associated with the working LSPs reserved. This is to make sure that LSPs reserved. This is to make sure that the service (working LSP)
the service (working LSP) can be reverted to the nominal path when can be reverted to the nominal path when the failure is repaired to
the failure is repaired to provide deterministic behavior and provide deterministic behavior and guaranteed Service Level Agreement
guaranteed Service Level Agreement (SLA). (SLA).
In this document, procedures are reviewed for GMPLS LSP associations, In this document, procedures are reviewed for GMPLS LSP associations,
resource sharing based LSP setup, teardown and LSP reversion for resource sharing based LSP setup, teardown, and LSP reversion for
non-packet transport networks, including following: non-packet transport networks, including the following:
o Review the procedure for providing LSP associations for the GMPLS o Review the procedure for providing LSP associations for the GMPLS
end-to-end recovery using restoration LSP where working and end-to-end recovery using restoration LSP where working and
protecting LSPs are not torn down and resources are kept reserved in protecting LSPs are not torn down and resources are kept reserved
the network after the failure. in the network after the failure.
o In [RFC3209], the make-before-break (MBB) method assumes the old o In [RFC3209], the make-before-break (MBB) method assumes the old
and new LSPs share the SESSION object and signal Shared Explicit (SE) and new LSPs share the SESSION object and signal Shared Explicit
flag in SESSION_ATTRIBUTE object for sharing resources. According to (SE) flag in SESSION_ATTRIBUTE object for sharing resources.
[RFC6689], ASSOCIATION object with Association Type "Resource According to [RFC6689], an ASSOCIATION object with Association
Sharing" enables the sharing of resources across LSPs with different Type "Resource Sharing" enables the sharing of resources across
SESSION objects. Procedure for resource sharing using the SE flag in LSPs with different SESSION objects. The procedure for resource
conjunction with ASSOCIATION object is discussed in this document. sharing using the SE flag in conjunction with an ASSOCIATION
object is discussed in this document.
o When using end-to-end recovery with revertive mode, methods for o When using end-to-end recovery with revertive mode, methods for
LSP reversion and resource sharing are summarized in this document. LSP reversion and resource sharing are summarized in this
document.
This document is strictly informative in nature and does not define This document is strictly informative in nature and does not define
any RSVP-TE signaling extensions. any RSVP-TE signaling extensions.
2. Overview 2. Overview
The GMPLS end-to-end recovery scheme, as defined in [RFC4872] and The GMPLS end-to-end recovery scheme, as defined in [RFC4872] and
being considered in this document, "fully dynamic rerouting switches being considered in this document, "fully dynamic rerouting switches
normal traffic to an alternate LSP that is not even partially normal traffic to an alternate LSP that is not even partially
established only after the working LSP failure occurs. The new established only after the working LSP failure occurs. The new
alternate route is selected at the LSP head-end node, it may reuse alternate route is selected at the LSP head-end node, it may reuse
resources of the failed LSP at intermediate nodes and may include resources of the failed LSP at intermediate nodes and may include
additional intermediate nodes and/or links". Two examples, 1+R and additional intermediate nodes and/or links". Two examples, 1+R and
1+1+R are described in the following sections. 1+1+R are described in the following sections.
2.1. 1+R Restoration 2.1. 1+R Restoration
One example of the recovery scheme considered in this document is 1+R One example of the recovery scheme considered in this document is 1+R
recovery. The 1+R recovery is exemplified in Figure 1. In this recovery. The 1+R recovery is exemplified in Figure 1. In this
example, working LSP on path A-B-C-Z is pre-established. Typically example, a working LSP on path A-B-C-Z is pre-established. Typically
after a failure detection and notification on the working LSP, a after a failure detection and notification on the working LSP, a
second LSP on path A-H-I-J-Z is established as a restoration LSP. second LSP on path A-H-I-J-Z is established as a restoration LSP.
Unlike protection LSP, restoration LSP is signaled per need basis. Unlike a protection LSP, a restoration LSP is signaled per need
basis.
+-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+
| A +----+ B +-----+ C +-----+ Z | | A +----+ B +-----+ C +-----+ Z |
+--+--+ +-----+ +-----+ +--+--+ +--+--+ +-----+ +-----+ +--+--+
\ / \ /
\ / \ /
+--+--+ +-----+ +--+--+ +--+--+ +-----+ +--+--+
| H +-------+ I +--------+ J | | H +-------+ I +--------+ J |
+-----+ +-----+ +-----+ +-----+ +-----+ +-----+
Figure 1: An Example of 1+R Recovery Scheme Figure 1: An Example of 1+R Recovery Scheme
During failure switchover with 1+R recovery scheme, in general, During failure switchover with 1+R recovery scheme, in general,
working LSP resources are not released so that working and working LSP resources are not released so that working and
restoration LSPs coexist in the network. Nonetheless, working and restoration LSPs coexist in the network. Nonetheless, working and
restoration LSPs can share network resources. Typically when failure restoration LSPs can share network resources. Typically when the
is recovered on the working LSP, restoration LSP is no longer failure has recovered on the working LSP, the restoration LSP is no
required and torn down, while the traffic is reverted to the original longer required and is torn down while the traffic is reverted to the
working LSP. original working LSP.
2.2. 1+1+R Restoration 2.2. 1+1+R Restoration
Another example of the recovery scheme considered in this document is Another example of the recovery scheme considered in this document is
1+1+R. In 1+1+R, a restoration LSP is signaled for the working LSP 1+1+R. In 1+1+R, a restoration LSP is signaled for the working LSP
and/or the protecting LSP after the failure has been detected, and and/or the protecting LSP after the failure has been detected, and
this recovery is exemplified in Figure 2. this recovery is exemplified in Figure 2.
+-----+ +-----+ +-----+ +-----+ +-----+ +-----+
| D +-------+ E +--------+ F | | D +-------+ E +--------+ F |
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| A +----+ B +-----+ C +-----+ Z | | A +----+ B +-----+ C +-----+ Z |
+--+--+ +-----+ +-----+ +--+--+ +--+--+ +-----+ +-----+ +--+--+
\ / \ /
\ / \ /
+--+--+ +-----+ +--+--+ +--+--+ +-----+ +--+--+
| H +-------+ I +--------+ J | | H +-------+ I +--------+ J |
+-----+ +-----+ +-----+ +-----+ +-----+ +-----+
Figure 2: An Example of 1+1+R Recovery Scheme Figure 2: An Example of 1+1+R Recovery Scheme
In this example, working LSP on path A-B-C-Z and protecting LSP on In this example, a working LSP on path A-B-C-Z and a protecting LSP
path A-D-E-F-Z are pre-established. After a failure detection and on path A-D-E-F-Z are pre-established. After a failure detection and
notification on a working LSP or protecting LSP, a third LSP on path notification on a working LSP or protecting LSP, a third LSP on path
A-H-I-J-Z is established as a restoration LSP. The restoration LSP A-H-I-J-Z is established as a restoration LSP. The restoration LSP
in this case provides protection against a second order failure. in this case provides protection against a second order failure.
During failure switchover with 1+1+R recovery scheme, in general, During failure switchover with 1+1+R recovery scheme, in general,
failed LSP resources are not released so that working, protecting and failed LSP resources are not released so that working, protecting and
restoration LSPs coexist in the network. Nonetheless, restoration restoration LSPs coexist in the network. Nonetheless, a restoration
LSP with working LSP it is restoring as well as restoration LSP with LSP with the working LSP it is restoring as well as a restoration LSP
protecting LSP it is restoring can share network resources. with the protecting LSP it is restoring can share network resources.
Typically, restoration LSP is torn down when the failure on the Typically, restoration LSP is torn down when the failure on the
original (working or protecting) LSP is repaired and the traffic is original (working or protecting) LSP is repaired and the traffic is
reverted to the original LSP. reverted to the original LSP.
There are four possible models when using restoration LSP with 1+1+R There are four possible models when using a restoration LSP with
recovery scheme: 1+1+R recovery scheme:
o A restoration LSP is signaled after either working or protecting o A restoration LSP is signaled after either a working or protecting
LSP fails. Only one restoration LSP is present at a time. LSP fails. Only one restoration LSP is present at a time.
o A restoration LSP is signaled after either working or protecting o A restoration LSP is signaled after either a working or protecting
LSP fails. Two different restoration LSPs may be present, one for LSP fails. Two different restoration LSPs may be present, one for
the working LSP and one for the protecting LSP. the working LSP and one for the protecting LSP.
o A restoration LSP is signaled after both working and protecting o A restoration LSP is signaled after both working and protecting
LSPs fail. Only one restoration LSP is present. LSPs fail. Only one restoration LSP is present.
o Two different restoration LSPs are signaled after both working and o Two different restoration LSPs are signaled after both working and
protecting LSPs fail, one for the working LSP and one for the protecting LSPs fail, one for the working LSP and one for the
protecting LSP. protecting LSP.
In all models discussed, if the restoration LSP also fails, it is In all models discussed, if the restoration LSP also fails, it is
torn down and a new restoration LSP is signaled. torn down and a new restoration LSP is signaled.
2.3. Resource Sharing By Restoration LSP 2.3. Resource Sharing By Restoration LSP
+-----+ +-----+ +-----+ +-----+
| F +------+ G +--------+ | F +------+ G +--------+
+--+--+ +-----+ | +--+--+ +-----+ |
| | | |
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is signaled with P bit cleared in the PROTECTION object and the is signaled with P bit cleared in the PROTECTION object and the
restoration LSP used for a protecting LSP is signaled with P bit set restoration LSP used for a protecting LSP is signaled with P bit set
in the PROTECTION object. in the PROTECTION object.
3.2. Resource Sharing-based Restoration LSP Setup 3.2. Resource Sharing-based Restoration LSP Setup
GMPLS LSPs can share resources during LSP setup if they have Shared GMPLS LSPs can share resources during LSP setup if they have Shared
Explicit (SE) flag set in their SESSION_ATTRIBUTE objects and: Explicit (SE) flag set in their SESSION_ATTRIBUTE objects and:
o As defined in [RFC3209], LSPs have identical SESSION objects o As defined in [RFC3209], LSPs have identical SESSION objects
and/or and/or
o As defined in [RFC6689], LSPs have matching ASSOCIATION object o As defined in [RFC6689], LSPs have matching ASSOCIATION object
with Association Type set to "Resource Sharing". LSPs in this case with Association Type set to "Resource Sharing". LSPs in this
can have different SESSION objects i.e. different Tunnel ID, Source case can have different SESSION objects i.e. different Tunnel ID,
and/or Destination. Source and/or Destination.
As described in [RFC3209], Section 2.5, the purpose of make-before- As described in [RFC3209], Section 2.5, the purpose of make-before-
break is "not to disrupt traffic, or adversely impact network break is "not to disrupt traffic, or adversely impact network
operations while TE tunnel rerouting is in progress". In non-packet operations while TE tunnel rerouting is in progress". In non-packet
transport networks, the label has a mapping into the data plane transport networks, the label has a mapping into the data plane
resource used and the nodes along the LSP need to send triggering resource used and the nodes along the LSP need to send triggering
commands to data plane for setting up cross-connections accordingly commands to data plane for setting up cross-connections accordingly
during the RSVP-TE signaling procedure. Due to the nature of the during the RSVP-TE signaling procedure. Due to the nature of the
non-packet transport networks, node may not be able to fulfill this non-packet transport networks, a node may not be able to fulfill this
purpose when sharing resources in some scenarios. purpose when sharing resources in some scenarios.
For LSP restoration upon failure, as explained in Section 11 of For LSP restoration upon failure, as explained in Section 11 of
[RFC4872], reroute procedure may re-use existing resources. The [RFC4872], the reroute procedure may re-use existing resources. The
behavior of the intermediate nodes during rerouting process to behavior of the intermediate nodes during the rerouting process to
reconfigure cross-connections does not further impact the traffic reconfigure cross-connections does not further impact the traffic
since it has been interrupted due to the already failed LSP. since it has been interrupted due to the already failed LSP.
The node behavior for setting up the restoration LSP can be The node behavior for setting up the restoration LSP can be
categorized into the following three categories: categorized into the following three categories:
Table 1: Node Behavior during Restoration LSP Setup Table 1: Node Behavior during Restoration LSP Setup
---------+--------------------------------------------------------- ---------+---------------------------------------------------------
Category | Node Behavior during Restoration LSP Setup Category | Node Behavior during Restoration LSP Setup
---------+--------------------------------------------------------- ---------+---------------------------------------------------------
C1 + Reusing existing resource on both input and output C1 + Reusing existing resource on both input and output
+ interfaces (nodes A & B in Figure 3). + interfaces (nodes A & B in Figure 3).
+ +
+ This type of nodes only needs to book the existing + This type of node needs to book the existing
+ resources and no cross-connection setup + resources and no cross-connection setup
+ command is needed. + command is needed.
---------+--------------------------------------------------------- ---------+---------------------------------------------------------
C2 + Reusing existing resource only on one of the interfaces, C2 + Reusing existing resource only on one of the interfaces,
+ either input or output interfaces and need to use new + either input or output interfaces and need to use new
+ resource on the other interface. + resource on the other interface.
+ (nodes C & E in Figure 3). + (nodes C & E in Figure 3).
+ +
+ This type of nodes needs to book the resources and send + This type of node needs to book the resources and send
+ the re-configuration cross-connection command to its + the re-configuration cross-connection command to its
+ corresponding data plane node on the interfaces where new + corresponding data plane node on the interfaces where new
+ resources are needed and re-use the + resources are needed and re-use the
+ existing resources on the other interfaces. + existing resources on the other interfaces.
---------+--------------------------------------------------------- ---------+---------------------------------------------------------
C3 + Using new resources on both interfaces. C3 + Using new resources on both interfaces.
+ (nodes F & G in Figure 3). + (nodes F & G in Figure 3).
+ +
+ This type of nodes needs to book the new resources + This type of node needs to book the new resources
+ and send the cross-connection setup + and send the cross-connection setup
+ command on both interfaces. + command on both interfaces.
---------+--------------------------------------------------------- ---------+---------------------------------------------------------
Depending on whether the resource is re-used or not, the node Depending on whether the resource is re-used or not, the node
behaviors differ. This deviates from normal LSP setup since some behaviors differ. This deviates from normal LSP setup since some
nodes do not need to re-configure the cross-connection, and it should nodes do not need to re-configure the cross-connection, and it should
not be viewed as an error. Also, the judgment whether the control not be viewed as an error. Also, the judgment whether the control
plane node needs to send a cross-connection setup/modification plane node needs to send a cross-connection setup/modification
command to its corresponding data plane node(s) relies on the check command to its corresponding data plane node(s) relies on the check
whether the LSPs are sharing resources. whether the LSPs are sharing resources.
3.3. LSP Reversion 3.3. LSP Reversion
If the end-to-end LSP recovery is revertive, as described in Section If the end-to-end LSP recovery is revertive, as described in Section
2, traffic can be reverted from the restoration LSP to the working or 2, traffic can be reverted from the restoration LSP to the working or
protecting LSP after its failure is recovered. The LSP reversion can protecting LSP after its failure is recovered. The LSP reversion can
be achieved using two methods: be achieved using two methods:
1. Make-while-break Reversion, where resources associated with 1. Make-while-break Reversion, where resources associated with a
working or protecting LSP are reconfigured while removing working or protecting LSP are reconfigured while removing
reservations for the restoration LSP. reservations for the restoration LSP.
2. Make-before-break Reversion, where resources associated with 2. Make-before-break Reversion, where resources associated with a
working or protecting LSP are reconfigured before removing working or protecting LSP are reconfigured before removing
reservations for the restoration LSP. reservations for the restoration LSP.
In non-packet transport networks, both of the above reversion methods In non-packet transport networks, both of the above reversion methods
will result in some traffic disruption when the restoration LSP and will result in some traffic disruption when the restoration LSP and
the LSP being restored are sharing resources and the the LSP being restored are sharing resources and the
cross-connections need to be reconfigured on intermediate nodes. cross-connections need to be reconfigured on intermediate nodes.
3.3.1. Make-while-break Reversion 3.3.1. Make-while-break Reversion
In this reversion method, restoration LSP is simply requested to be In this reversion method, restoration LSP is simply requested to be
deleted by the head-end. Removing reservations for restoration LSP deleted by the head-end. Removing reservations for restoration LSP
triggers reconfiguration of resources associated with working or triggers reconfiguration of resources associated with a working or
protecting LSP on every node where resources are shared. Whenever protecting LSP on every node where resources are shared. Whenever
reservation for restoration LSP is removed from a node, data plane reservation for restoration LSP is removed from a node, data plane
configuration changes to reflect reservations of working or configuration changes to reflect reservations of working or
protection LSP as signaling progresses. Eventually, after the whole protection LSP as signaling progresses. Eventually, after the whole
restoration LSP is deleted, data plane configuration will fully match restoration LSP is deleted, data plane configuration will fully match
working or protecting LSP reservations on the whole path. Thus working or protecting LSP reservations on the whole path. Thus
reversion is complete. reversion is complete.
Make-while-break, while being relatively simple in its logic, has few Make-while-break, while being relatively simple in its logic, has a
limitations as follows which may not be acceptable in some networks: few limitations as follows which may not be acceptable in some
networks:
o No rollback o No rollback
Deletion of restoration LSPs is not a revertive process. If for some Deletion of restoration LSPs is not a revertive process. If for some
reason reconfiguration of data plane on one of the nodes to match reason reconfiguration of data plane on one of the nodes to match
working or protection LSP reservations fails, falling back to working or protection LSP reservations fails, falling back to
restoration LSP is no longer an option, as its state might have restoration LSP is no longer an option, as its state might have
already been removed from other nodes. already been removed from other nodes.
o No completion guarantee o No completion guarantee
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eventually remove remaining reservations due to refresh timeouts. eventually remove remaining reservations due to refresh timeouts.
This approach is not feasible in non-packet transport networks This approach is not feasible in non-packet transport networks
however, where control and data channels are often separated and however, where control and data channels are often separated and
hence soft state reservations are not useful. hence soft state reservations are not useful.
Finally, one could argue that graceful LSP deletion [RFC3473] would Finally, one could argue that graceful LSP deletion [RFC3473] would
provide guarantee of completion. While this is true for most cases, provide guarantee of completion. While this is true for most cases,
many implementations will time out graceful deletion if LSP is not many implementations will time out graceful deletion if LSP is not
removed within certain amount of time, e.g. due to a transit node removed within certain amount of time, e.g. due to a transit node
fault. After that, deletion procedures which provide no completion fault. After that, deletion procedures which provide no completion
guarantees will be attempted. Hence, in corner cases completion guarantees will be attempted. Hence, in corner cases a completion
guarantee cannot be provided. guarantee cannot be provided.
o No explicit notification of completion to head-end node o No explicit notification of completion to head-end node
In some cases, it may be useful for a head-end node to know when the In some cases, it may be useful for a head-end node to know when the
data plane has been reconfigured to match working or protection LSP data plane has been reconfigured to match working or protection LSP
reservations. This knowledge could be used for initiating operations reservations. This knowledge could be used for initiating operations
like enabling alarm monitoring, power equalization and others. like enabling alarm monitoring, power equalization and others.
Unfortunately, for the reasons mentioned above, make-while-break Unfortunately, for the reasons mentioned above, make-while-break
reversion lacks such explicit notification. reversion lacks such explicit notification.
3.3.2. Make-before-break Reversion 3.3.2. Make-before-break Reversion
This reversion method can be used to overcome limitations of This reversion method can be used to overcome limitations of
make-while-break reversion. It is similar in spirit to MBB concept make-while-break reversion. It is similar in spirit to MBB concept
used for re-optimization. Instead of relying on deletion of used for re-optimization. Instead of relying on deletion of
restoration LSP, head-end chooses to establish a new LSP to restoration LSP, the head-end chooses to establish a new LSP to
reconfigure resources on the working or protection LSP path, and uses reconfigure resources on the working or protection LSP path, and uses
identical ASSOCIATION and PROTECTION objects from the LSP it is identical ASSOCIATION and PROTECTION objects from the LSP it is
replacing. Only if setup of this LSP is successful will other replacing. Only if setup of this LSP is successful will other
(restoration and working/protecting) LSPs be deleted by the head-end. (restoration and working/protecting) LSPs be deleted by the head-end.
MBB reversion consists of two parts: MBB reversion consists of two parts:
A) Make part: A) Make part:
Creating a new reversion LSP following working or protection LSP's Creating a new reversion LSP following working or protection LSP's
path. Reversion LSP is sharing resources both with working and path. Reversion LSP is sharing resources both with working and
skipping to change at page 13, line 10 skipping to change at page 13, line 10
[RFC4427] Mannie, E., and Papadimitriou, D., "Recovery (Protection [RFC4427] Mannie, E., and Papadimitriou, D., "Recovery (Protection
and Restoration) Terminology for Generalized and Restoration) Terminology for Generalized
Multi-Protocol Label Switching", RFC 4427, March 2006. Multi-Protocol Label Switching", RFC 4427, March 2006.
Acknowledgements Acknowledgements
The authors would like to thank George Swallow for the discussions on The authors would like to thank George Swallow for the discussions on
the GMPLS restoration. The authors would like to thank Lou Berger the GMPLS restoration. The authors would like to thank Lou Berger
for the guidance on this work. The authors would also like to thank for the guidance on this work. The authors would also like to thank
Lou Berger and Vishnu Pavan Beeram for reviewing this document and Lou Berger, Vishnu Pavan Beeram and Christian Hopps for reviewing
providing valuable comments. this document and providing valuable comments.
Contributors Contributors
Gabriele Maria Galimberti Gabriele Maria Galimberti
Cisco Systems, Inc. Cisco Systems, Inc.
EMail: ggalimbe@cisco.com EMail: ggalimbe@cisco.com
Authors' Addresses Authors' Addresses
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