draft-ietf-ccamp-gmpls-vcat-lcas-00.txt   draft-ietf-ccamp-gmpls-vcat-lcas-01.txt 
CCAMP Working Group G. Bernstein CCAMP Working Group G. Bernstein
Internet Draft Grotto Networking Internet Draft Grotto Networking
Updates: RFC 3946 D. Caviglia Updates: RFC 3946 D. Caviglia
Category: Standards Track Ericsson Category: Standards Track Ericsson
Expires: March 2007 R. Rabbat (ed.) Expires: April 2007 R. Rabbat (ed.)
Fujitsu Fujitsu
H. van Helvoort H. van Helvoort
Huawei Huawei
September 6, 2006 October 20, 2006
Operating Virtual Concatenation (VCAT) and the Link Capacity Operating Virtual Concatenation (VCAT) and the Link Capacity
Adjustment Scheme (LCAS) with Generalized Multi-Protocol Label Adjustment Scheme (LCAS) with Generalized Multi-Protocol Label
Switching (GMPLS) Switching (GMPLS)
draft-ietf-ccamp-gmpls-vcat-lcas-00.txt draft-ietf-ccamp-gmpls-vcat-lcas-01.txt
Status of this Memo Status of this Memo
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Abstract Abstract
This document describes requirements for, and use of, the Generalized This document describes requirements for, and use of, the Generalized
Multi-Protocol Label Switching (GMPLS) control plane in conjunction Multi-Protocol Label Switching (GMPLS) control plane in conjunction
with the Virtual Concatenation (VCAT) layer 1 inverse multiplexing with the Virtual Concatenation (VCAT) layer 1 inverse multiplexing
mechanism and its companion Link Capacity Adjustment Scheme (LCAS) mechanism and its companion Link Capacity Adjustment Scheme (LCAS)
which can be used for hitless dynamic resizing of the inverse which can be used for hitless dynamic resizing of the inverse
multiplex group. These techniques apply to the Optical Transport multiplex group. These techniques apply to the Optical Transport
Network (OTN), Synchronous Optical Network (SONET), Synchronous Network (OTN), Synchronous Optical Network (SONET), Synchronous
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3. VCAT/LCAS Scenarios and Specific Requirements..................3 3. VCAT/LCAS Scenarios and Specific Requirements..................3
3.1. Multiple VCAT Groups per GMPLS Endpoint...................3 3.1. Multiple VCAT Groups per GMPLS Endpoint...................3
3.2. Component Signal Configuration Requirements...............3 3.2. Component Signal Configuration Requirements...............3
3.3. VCAT Operation With or Without LCAS.......................4 3.3. VCAT Operation With or Without LCAS.......................4
4. GMPLS Mechanisms for Signaling VCAT/LCAS.......................4 4. GMPLS Mechanisms for Signaling VCAT/LCAS.......................4
4.1. Co-Routed Signals.........................................5 4.1. Co-Routed Signals.........................................5
4.1.1. One-shot Setup of Co-Routed Signal...................5 4.1.1. One-shot Setup of Co-Routed Signal...................5
4.1.2. Incremental Setup of Co-Routed Signal................5 4.1.2. Incremental Setup of Co-Routed Signal................5
4.1.3. Removing a Component Signal..........................6 4.1.3. Removing a Component Signal..........................6
4.1.4. Removing Multiple Component Signals in One Shot......6 4.1.4. Removing Multiple Component Signals in One Shot......6
4.1.5. Use of multiple LSPs for Co-Routed Signals...........6 4.1.5. Use of multiple LSPs for Co-Routed Signals...........7
4.1.6. Teardown of Whole VCG................................7 4.1.6. Teardown of Whole VCG................................7
4.2. Diversely Routed Signals..................................7 4.2. Diversely Routed Signals..................................7
4.2.1. Associating Diversely Routed Signals.................7 4.2.1. Associating Diversely Routed Signals.................7
4.2.2. Procedures for VCG Setup Using Diversely Routed 4.2.2. Procedures for VCG Setup Using Diversely Routed
Components..................................................8 Components..................................................8
4.2.3. Procedures for VCG Reduction/Teardown Using Diversely 4.2.3. Procedures for VCG Reduction/Teardown Using Diversely
Routed Components...........................................9 Routed Components...........................................9
4.2.4. Update of Already Established LSPs...................9 4.2.4. Update of Already Established LSPs...................9
4.2.5. One LSP per Circuit..................................9 4.2.5. One LSP per Circuit..................................9
5. IANA Considerations............................................9 5. IANA Considerations...........................................10
6. Security Considerations.......................................10 6. Security Considerations.......................................10
7. Contributors..................................................10 7. Contributors..................................................11
8. Acknowledgments...............................................10 8. Acknowledgments...............................................11
9. References....................................................11 9. References....................................................12
9.1. Normative References.....................................11 9.1. Normative References.....................................12
9.2. Informative References...................................11 9.2. Informative References...................................12
Author's Addresses...............................................12 Author's Addresses...............................................13
Intellectual Property Statement..................................13 Intellectual Property Statement..................................14
Disclaimer of Validity...........................................13 Disclaimer of Validity...........................................14
Copyright Statement..............................................14
Copyright Statement..............................................13 Acknowledgment...................................................15
Acknowledgment...................................................14
1. Introduction 1. Introduction
The Generalized Multi-Protocol Label Switching (GMPLS) suite of The Generalized Multi-Protocol Label Switching (GMPLS) suite of
protocols allows the automated control of different switching protocols allows the automated control of different switching
technologies including SONET/SDH. technologies including SONET/SDH.
This document describes extensions to RSVP-TE to support the Virtual This document describes extensions to RSVP-TE to support the Virtual
Concatenation (VCAT) layer 1 inverse multiplexing mechanism and its Concatenation (VCAT) layer 1 inverse multiplexing mechanism and its
companion Link Capacity Adjustment Scheme (LCAS). These extensions companion Link Capacity Adjustment Scheme (LCAS). These extensions
enable the setup of diversely routed circuits that are members of the enable the setup of diversely routed circuits that are members of the
same VCAT group. same VCAT group.
2. Changes from draft-bernstein-ccamp-gmpls-vcat-lcas-04 2. Changes from draft-ietf-ccamp-gmpls-vcat-lcas-00
o Updated reference from RFC3946bis to issued RFC4606 o Updated reference from RFC3946bis to issued RFC4606
o Updated section 3.2 based on discussions on the mailing list
3. VCAT/LCAS Scenarios and Specific Requirements 3. VCAT/LCAS Scenarios and Specific Requirements
There are a number of specific requirements for the support of There are a number of specific requirements for the support of
VCAT/LCAS in GMPLS that can be derived from the carriers' VCAT/LCAS in GMPLS that can be derived from the carriers'
application-specific demands for the use of VCAT/LCAS and from the application-specific demands for the use of VCAT/LCAS and from the
flexible nature of VCAT/LCAS. These are set out in the following flexible nature of VCAT/LCAS. These are set out in the following
section. section.
3.1. Multiple VCAT Groups per GMPLS Endpoint 3.1. Multiple VCAT Groups per GMPLS Endpoint
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at the same time have interfaces that are neither VCAT nor LCAS- at the same time have interfaces that are neither VCAT nor LCAS-
capable. capable.
3.2. Component Signal Configuration Requirements 3.2. Component Signal Configuration Requirements
We list in this section the different scenarios that SHOULD be We list in this section the different scenarios that SHOULD be
supported. Here we use the term "VCG" to refer to the entire VCAT supported. Here we use the term "VCG" to refer to the entire VCAT
group and the terminology "set" and "subset" to refer to the group and the terminology "set" and "subset" to refer to the
collection of potential VCAT group member signals. collection of potential VCAT group member signals.
Note that LCAS-capable interfaces can support all scenarios with no
loss of traffic.
o Fixed, co-routed: A fixed bandwidth VCG, transported over a co- o Fixed, co-routed: A fixed bandwidth VCG, transported over a co-
routed set of member signals. This is the case where the intended routed set of member signals. This is the case where the intended
bandwidth of the VCG does not change and all member signals follow bandwidth of the VCG does not change and all member signals follow
the same route and minimize differential delay. The intent here the same route and minimize differential delay. The intent here
is the capability to allocate an amount of bandwidth close to that is the capability to allocate an amount of bandwidth close to that
required at the client layer. required at the client layer.
o Fixed, diversely routed: A fixed bandwidth VCG, transported over o Fixed, diversely routed: A fixed bandwidth VCG, transported over
at least two diversely routed subsets of member signals. In this at least two diversely routed subsets of member signals. In this
case, the subsets are link-disjoint over at least one link of the case, the subsets are link-disjoint over at least one link of the
route. The intent here is more efficient use of network resources route. The intent here is more efficient use of network resources
(no unique route has the required bandwidth), and additional (no unique route has the required bandwidth).
resilience and graceful degradation in the case of failure (note
that differential delay may be a limiting factor).
o Dynamic, co-routed: A dynamic VCG (bandwidth can be increased or o Dynamic, co-routed: A dynamic VCG (bandwidth can be increased or
decreased via the addition or removal of member signals), decreased via the addition or removal of member signals),
transported over a co-routed set of members. Intent here is transported over a co-routed set of members. The intent here is
dynamic sizing of bandwidth. dynamic resizing and resilience of bandwidth.
o Dynamic, diversely routed: A dynamic VCAT group, transported over o Dynamic, diversely routed: A dynamic VCG (bandwidth can be
at least two diversely routed subsets of member signals. The increased or decreased via the addition or removal of member
intent here is dynamic resizing and resilience (but differential signals), transported over at least two diversely routed subsets
delay may be a limiting factor). of member signals. The intent here is efficient use of network
resources, dynamic resizing and resilience of bandwidth.
3.3. VCAT Operation With or Without LCAS 3.3. VCAT Operation With or Without LCAS
VCAT capabilities may be present with or without the presence of VCAT capabilities may be present with or without the presence of
LCAS. The use of LCAS is beneficial to the provision of services, LCAS. The use of LCAS is beneficial to the provision of services,
but in the absence of LCAS, VCAT is still a valid technique. but in the absence of LCAS, VCAT is still a valid technique.
Therefore GMPLS mechanisms for the operation of VCAT are REQUIRED for Therefore GMPLS mechanisms for the operation of VCAT are REQUIRED for
both the case where LCAS is available and the case where it is not both the case where LCAS is available and the case where it is not
available. The GMPLS procedures for the two cases SHOULD be available. The GMPLS procedures for the two cases SHOULD be
identical. identical.
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The existing signaling protocols support co-routed signal setup using The existing signaling protocols support co-routed signal setup using
the NVC field as explained in section 2.1 of [RFC4606]. In this the NVC field as explained in section 2.1 of [RFC4606]. In this
case, one single LSP is set up in support of the VCAT group. case, one single LSP is set up in support of the VCAT group.
There are two options for setting up the VCAT group, depending on There are two options for setting up the VCAT group, depending on
hardware capability, or management preferences: one-shot setup and hardware capability, or management preferences: one-shot setup and
incremental setup. incremental setup.
The following sections explain the procedure based on an example of The following sections explain the procedure based on an example of
setting up a VC4-7v SDH VCAT group (corresponding to an STS-3c-7v setting up a VC-4-7v SDH VCAT group (corresponding to an STS-3c-7v
SONET VCAT group). SONET VCAT group).
4.1.1. One-shot Setup of Co-Routed Signal 4.1.1. One-shot Setup of Co-Routed Signal
An RSVP-TE Path message is used with the following parameters. An RSVP-TE Path message is used with the following parameters.
With regards to the traffic parameters, the elementary signal is With regards to the traffic parameters, the elementary signal is
chosen (6 for VC-4/STS-3c_SPE). The value of NVC is then set to 7. chosen (6 for VC-4/STS-3c_SPE). The value of NVC is then set to 7.
A Multiplier Transform greater than 1 (say N>1) is used if the A Multiplier Transform greater than 1 (say N>1) is used if the
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Label (in the Path or Resv message). A node that receives a Path Label (in the Path or Resv message). A node that receives a Path
message that contains changed fields will process the full Path message that contains changed fields will process the full Path
message and, based on the new value of NVC, it will add a component message and, based on the new value of NVC, it will add a component
signal to the VCAT group, and switch the new timeslot based on the signal to the VCAT group, and switch the new timeslot based on the
new label information. new label information.
Following the addition of the new label to the LSP, LCAS may be used Following the addition of the new label to the LSP, LCAS may be used
in-band to add the new label into the existing VCAT group. LCAS in-band to add the new label into the existing VCAT group. LCAS
signaling for this function is described in [ITU-T-G.7042]. signaling for this function is described in [ITU-T-G.7042].
4.1.3. Removing a Component Signal 4.1.3. Procedure for VCG Reduction by Removing a Component Signal
A VCG member can be permanently removed from the VCG either as the
result of a management command or following a temporary removal (due
to a failure).
The procedure to remove a component signal is similar to that used to The procedure to remove a component signal is similar to that used to
add components as described in Section 4.1.2. The LCAS in-band add components as described in Section 4.1.2. The LCAS in-band
signaling step is taken first to take the component out of the group. signaling step is taken first to take the component out of the group.
LCAS signaling is described in [ITU-T-G.7042]. LCAS signaling is described in [ITU-T-G.7042].
In this case, the NVC value is decremented by 1 and the timeslot In this case, the NVC value is decremented by 1 and the timeslot
identifier for the dropped component is removed from the ordered list identifier for the dropped component is removed from the ordered list
in the Generalized Label. This function is not supported without in the Generalized Label.
management intervention for VCAT-only interfaces as removing one
Note that for interfaces that are not LCAS-capable, removing one
component of the VCG will result in errors in the inverse- component of the VCG will result in errors in the inverse-
multiplexing procedure of VCAT and result in the teardown of the multiplexing procedure of VCAT and result in the teardown of the
whole group. So, this is a feature that only LCAS-capable VCAT whole group. So, this is a feature that only LCAS-capable VCAT
interfaces can support without management intervention at the end interfaces can support without management intervention at the end
points. points.
4.1.4. Removing Multiple Component Signals in One Shot 4.1.4. Removing Multiple Component Signals in One Shot
The procedure is similar to 4.1.3. In this case, the NVC value is The procedure is similar to 4.1.3. In this case, the NVC value is
changed to the new value and all relevant timeslot identifiers for changed to the new value and all relevant timeslot identifiers for
the components to be torn down are removed from the ordered list in the components to be torn down are removed from the ordered list in
the Generalized Label. This is also not supported for VCAT-only the Generalized Label. This procedure is also not supported for
interfaces without management intervention as removing one component VCAT-only interfaces without management intervention as removing one
of the VCG will tear down the whole group, but the use of LCAS can or more components of the VCG will tear down the whole group.
facilitate this procedure.
4.1.5. Use of multiple LSPs for Co-Routed Signals 4.1.5. Use of multiple LSPs for Co-Routed Signals
Co-routed signals may also be supported by distinct LSPs signaled Co-routed signals may also be supported by distinct LSPs signaled
separately using exactly the techniques described for diversely separately using exactly the techniques described for diversely
routed signals in Section 4.2. routed signals in Section 4.2.
4.1.6. Teardown of Whole VCG 4.1.6. Teardown of Whole VCG
The entire LSP is deleted in a single step (i.e., all components are The entire LSP is deleted in a single step (i.e., all components are
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3, and each Path message MUST use the same Association ID. 3, and each Path message MUST use the same Association ID.
Following the addition of each new LSP (i.e., once the RESV message Following the addition of each new LSP (i.e., once the RESV message
has been received by the ingress LSR), LCAS signaling is used in-band has been received by the ingress LSR), LCAS signaling is used in-band
to hitlessly add the new label into the existing group [ITU-T- to hitlessly add the new label into the existing group [ITU-T-
G.7042]. G.7042].
4.2.3. Procedures for VCG Reduction/Teardown Using Diversely Routed 4.2.3. Procedures for VCG Reduction/Teardown Using Diversely Routed
Components Components
To remove the component circuits on any route, LCAS signaling is used To remove the component circuits on any route, LCAS in-band signaling
in-band to remove the labels associated with the LSP from the group. is used to remove the labels associated with the LSP from the group.
LCAS signaling is defined in [ITU-T-G.7042]. LCAS signaling is defined in [ITU-T-G.7042].
In addition, the procedures outlined in section 4.1.3 or 4.1.4 are In addition, the procedures outlined in section 4.1.3 or 4.1.4 are
used to tear down the unwanted LSP. used to tear down the unwanted LSP.
Again, this can only be done on LCAS-capable interfaces. If the Again, this can only be done on LCAS-capable interfaces. If the
procedure is attempted on VCAT-only interfaces, then the whole VCG is procedure is attempted on VCAT-only interfaces, then the whole VCG is
torn down (this is not a graceful teardown so ingress/egress initiate torn down (this is not a graceful teardown so ingress/egress initiate
a Path Tear/Resv Tear) on all routes. a Path Tear/Resv Tear) on all routes.
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Ciena Ciena
PO Box 308 PO Box 308
Cupertino, CA 95015 Cupertino, CA 95015
United States of America United States of America
Phone: +1 408 705 2978 Phone: +1 408 705 2978
Email: lyong@ciena.com Email: lyong@ciena.com
8. Acknowledgments 8. Acknowledgments
The authors would like to thank Maarten Vissers and Adrian Farrel for The authors would like to thank Maarten Vissers, Trevor Wilson and
extensive reviews and contributions to this draft. Adrian Farrel for extensive reviews and contributions to this draft.
9. References 9. References
9.1. Normative References 9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2205] Braden, R., Zhang, L., Berson, S., Herzog, S. and S. [RFC2205] Braden, R., Zhang, L., Berson, S., Herzog, S. and S.
Jamin, "Resource ReSerVation Protocol (RSVP) -- Jamin, "Resource ReSerVation Protocol (RSVP) --
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9.2. Informative References 9.2. Informative References
[ANSI-T1.105] American National Standards Institute, "Synchronous [ANSI-T1.105] American National Standards Institute, "Synchronous
Optical Network (SONET) - Basic Description including Optical Network (SONET) - Basic Description including
Multiplex Structure, Rates, and Formats", ANSI T1.105- Multiplex Structure, Rates, and Formats", ANSI T1.105-
2001, May 2001. 2001, May 2001.
[ITU-T-G.7042] International Telecommunications Union, "Link Capacity [ITU-T-G.7042] International Telecommunications Union, "Link Capacity
Adjustment Scheme (LCAS) for Virtual Concatenated Adjustment Scheme (LCAS) for Virtual Concatenated
Signals", ITU-T Recommendation G.7042, February 2004. Signals", ITU-T Recommendation G.7042, March 2006.
[ITU-T-G.7043] International Telecommunications Union, "Virtual [ITU-T-G.7043] International Telecommunications Union, "Virtual
Concatenation of Plesiochronous Digital Hierarchy Concatenation of Plesiochronous Digital Hierarchy
(PDH) Signals", ITU-T Recommendation G.7043, July (PDH) Signals", ITU-T Recommendation G.7043, July
2004. 2004.
[ITU-T-G.707] International Telecommunications Union, "Network Node [ITU-T-G.707] International Telecommunications Union, "Network Node
Interface for the Synchronous Digital Hierarchy Interface for the Synchronous Digital Hierarchy
(SDH)", ITU-T Recommendation G.707, December 2003. (SDH)", ITU-T Recommendation G.707, December 2003.
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