draft-ietf-ccamp-gmpls-vcat-lcas-09.txt   draft-ietf-ccamp-gmpls-vcat-lcas-10.txt 
CCAMP Working Group G. Bernstein (ed.) CCAMP Working Group G. Bernstein (ed.)
Internet Draft Grotto Networking Internet Draft Grotto Networking
Updates: RFC 3946 D. Caviglia Updates: RFC4606 D. Caviglia
Category: Standards Track Ericsson Category: Standards Track Ericsson
Expires: July 2010 R. Rabbat Expires: January 2011 R. Rabbat
Google Google
H. van Helvoort H. van Helvoort
Huawei Huawei
January 11, 2010 July 12, 2010
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-09.txt draft-ietf-ccamp-gmpls-vcat-lcas-10.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 support of
with the Virtual Concatenation (VCAT) layer 1 inverse multiplexing the Virtual Concatenation (VCAT) layer 1 inverse multiplexing data
mechanism and its companion Link Capacity Adjustment Scheme (LCAS) plane mechanism and its companion Link Capacity Adjustment Scheme
which can be used for hitless dynamic resizing of the inverse (LCAS) which can be used for hitless dynamic resizing of the inverse
multiplex group. These techniques apply to Optical Transport Network multiplex group. These techniques apply to Optical Transport Network
(OTN), Synchronous Optical Network (SONET), Synchronous Digital (OTN), Synchronous Optical Network (SONET), Synchronous Digital
Hierarchy (SDH), and Plesiochronous Digital Hierarchy (PDH) signals. Hierarchy (SDH), and Plesiochronous Digital Hierarchy (PDH) signals.
This document updates the procedures for supporting virtual
concatenation in [RFC4606].
Conventions used in this document Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC-2119 [RFC2119]. document are to be interpreted as described in RFC-2119 [RFC2119].
Table of Contents Table of Contents
1. Introduction......................................... 3 1. Introduction...................................................3
2. VCAT/LCAS Scenarios and Specific Requirements ............. 4 2. VCAT/LCAS Scenarios and Specific Requirements..................4
2.1. VCAT/LCAS Interface Capabilities.................... 4 2.1. VCAT/LCAS Interface Capabilities..........................4
2.2. Member Signal Configuration Scenarios................ 4 2.2. Member Signal Configuration Scenarios.....................4
2.3. VCAT Operation With or Without LCAS.................. 5 2.3. VCAT Operation With or Without LCAS.......................5
2.4. VCGs and VCG Members.............................. 6 2.4. VCGs and VCG Members......................................6
3. VCAT Data and Control Plane Concepts..................... 6 3. VCAT Data and Control Plane Concepts...........................6
4. VCGs Composed of a Single Co-Signaled Member Set (One LSP)... 7 4. VCGs Composed of a Single Co-Signaled Member Set...............7
4.1. One-shot VCG Setup with Co-Signaled Members........... 7 4.1. One-shot VCG Setup with Co-Signaled Members...............7
4.2. Incremental VCG Setup with Co-Signaled Members......... 7 4.2. Incremental VCG Setup with Co-Signaled Members............8
4.3. Procedure for VCG Reduction by Removing a Member....... 8 4.3. Procedure for VCG Reduction by Removing a Member..........8
4.4. Removing Multiple VCG Members in One Shot............. 9 4.4. Removing Multiple VCG Members in One Shot.................9
4.5. Teardown of Whole VCG............................. 9 4.5. Teardown of Whole VCG.....................................9
5. VCGs Composed of Multiple Co-Signaled Member Sets(Multiple LSPs)9 5. VCGs Composed of Multiple Co-Signaled Member Sets(Multiple LSPs)9
5.1. Signaled VCG Service Layer Information.............. 10 5.1. Signaled VCG Service Layer Information...................10
5.2. VCAT TLV....................................... 11 5.2. VCAT TLV.................................................11
5.3. Procedures for Multiple Co-signaled Member Sets....... 13 5.3. Procedures for Multiple Co-signaled Member Sets..........13
5.3.1. Setting up a new VCAT call and VCG Simultaneously. 13 5.3.1. Setting up a new VCAT call and VCG Simultaneously...13
5.3.2. Setting up a VCAT call + LSPs without a VCG...... 13 5.3.2. Setting up a VCAT call + LSPs without a VCG.........13
5.3.3. Associating an existing VCAT call with a new VCG.. 14 5.3.3. Associating an existing VCAT call with a new VCG....14
5.3.4. Removing the association between a call and VCG... 14 5.3.4. Removing the association between a call and VCG.....14
5.3.5. VCG Bandwidth modification.................... 14 5.3.5. VCG Bandwidth modification..........................14
6. Error Conditions and Codes............................ 15 6. Error Conditions and Codes....................................15
7. IANA Considerations.................................. 16 7. IANA Considerations...........................................16
7.1. RSVP CALL_ATTRIBUTE TLV .......................... 16 7.1. RSVP CALL_ATTRIBUTE TLV..................................16
7.2. RSVP Error Codes and Error Values.................. 16 7.2. RSVP Error Codes and Error Values........................16
8. Security Considerations............................... 17 8. Security Considerations.......................................17
9. Contributors........................................ 18 9. Contributors..................................................18
10. Acknowledgments.................................... 18 10. Acknowledgments..............................................18
11. References ........................................ 19 11. References...................................................19
11.1. Normative References............................ 19 11.1. Normative References....................................19
11.2. Informative References .......................... 19 11.2. Informative References..................................19
Author's Addresses..................................... 20 Author's Addresses...............................................20
Intellectual Property Statement .......................... 21 Intellectual Property Statement..................................21
Disclaimer of Validity.................................. 21 Disclaimer of Validity...........................................21
Acknowledgment ........................................ 21 Acknowledgment...................................................21
1. Introduction 1. Introduction
The Generalized Multi-Protocol Label Switching (GMPLS) suite of The Generalized Multi-Protocol Label Switching (GMPLS) suite of
protocols allows for the automated control of different switching protocols allows for the automated control of different switching
technologies including Synchronous Optical Network (SONET)[ANSI- technologies including Synchronous Optical Network (SONET)[ANSI-
T1.105], Synchronous Digital Hierarchy (SDH)[ITU-T-G.707], Optical T1.105], Synchronous Digital Hierarchy (SDH)[ITU-T-G.707], Optical
Transport Network (OTN)[ITU-T-G.709] and Plesiochronous Digital Transport Network (OTN)[ITU-T-G.709] and Plesiochronous Digital
Hierarchy (PDH)[ITU-T-G.704]. This document describes extensions to Hierarchy (PDH)[ITU-T-G.704]. This document updates the procedures of
RSVP-TE to support the Virtual Concatenation (VCAT) layer 1 inverse [RFC4606] to allow supporting additional applications of the Virtual
multiplexing mechanism that has been standardized for SONET, SDH, OTN Concatenation (VCAT) layer 1 inverse multiplexing mechanism that has
and PDH [ITU-T-G.7043] technologies along with its companion Link been standardized for SONET, SDH, OTN and PDH [ITU-T-G.707, ITU-T-
G.709, and ITU-T-G.7043] technologies along with its companion Link
Capacity Adjustment Scheme (LCAS) [ITU-T-G.7042]. Capacity Adjustment Scheme (LCAS) [ITU-T-G.7042].
VCAT is a TDM oriented byte striping inverse multiplexing method that VCAT is a TDM oriented byte striping inverse multiplexing method that
works with a wide range of existing and emerging TDM framed signals, works with a wide range of existing and emerging TDM framed signals,
including very high bit rate OTN and SDH/SONET signals. Other than including very high bit rate OTN and SDH/SONET signals. VCAT enables
member signal skew compensation this layer 1 inverse multiplexing the selection of an optimal signal server bandwidth (size) utilizing
mechanism adds minimal additional signal delay. VCAT enables the a group of server signals and provides for efficient use of bandwidth
selection of an optimal signal bandwidth (size), extraction of in a mesh network. When combined with LCAS, hitless dynamic resizing
bandwidth from a mesh network, and, when combined with LCAS, hitless of bandwidth and fast graceful degradation in the presence of network
dynamic resizing of bandwidth and fast graceful degradation in the faults can be supported. To take full advantage of VCAT/LCAS
presence of network faults. To take full advantage of VCAT/LCAS functionality, additional extensions to GMPLS signaling are needed
functionality extensions to GMPLS signaling are given that enable the that enable the setup of diversely routed signals that are members of
setup of diversely routed circuits that are members of the same VCAT the same VCAT group. Note that the scope of this document is limited
group. Note that the scope of the document is limited to scenarios to scenarios where all member signals of a VCAT group are controlled
where all member signals of a VCAT group are controlled using using mechanisms defined in this document and related RFCs. Scenarios
mechanisms defined in this document and related RFCs. Scenarios where where a subset of member signals are controlled by a management plane
a subset of member signals are controlled by a mangement plane or or a proprietary control plane are beyond the scope of this document.
proprietary control plane are outside the scope of this document.
2. VCAT/LCAS Scenarios and Specific Requirements 2. 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 applications for the use of VCAT/LCAS. These are set out in the
flexible nature of VCAT/LCAS. These are set out in the following following section.
section.
2.1. VCAT/LCAS Interface Capabilities 2.1. VCAT/LCAS Interface Capabilities
In general, an LSR can be ingress/egress of one or more VCAT groups. In general, an LSR can be ingress/egress of one or more VCAT groups.
VCAT and LCAS are interface capabilities. An LSR may have, for VCAT and LCAS are interface capabilities. An LSR may have, for
example, VCAT-capable interfaces that are not LCAS-capable. It may example, VCAT-capable interfaces that are not LCAS-capable. It may
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.
2.2. Member Signal Configuration Scenarios 2.2. Member Signal Configuration Scenarios
We list in this section the different scenarios. Here we use the We list in this section the different scenarios. Here we use the
term "VCG" to refer to the entire VCAT group and the terminology [ITU-T-G.707] term "VCG" to refer to the VCAT group and the
"set" and "subset" to refer to the collection of potential VCAT group terminology "set" and "subset" to refer to the subdivision of the
member signals. It should be noted that the scope of these scenarios group and the individual VCAT group member signals. As noted above,
is limited to situations where all member signals are controlled the scope of these scenarios is limited to scenarios where all member
using mechanisms defined in this document. signals are controlled using mechanisms defined in this document.
o Fixed, co-routed: A fixed bandwidth VCG, transported over a co- Fixed, co-routed: A fixed bandwidth VCG, transported over a co-routed
routed set of member signals. This is the case where the intended 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 to minimize differential delay. The intent here is the same route to minimize differential delay. The application
the capability to allocate an amount of bandwidth close to that here is the capability to allocate an amount of bandwidth close to
required at the client layer. that required at the client layer.
o Fixed, diversely routed: A fixed bandwidth VCG, transported over Fixed, diversely routed: A fixed bandwidth VCG, transported over at
at least two diversely routed subsets of member signals. In this 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 route. The application here is more efficient use of network
resources, e.g., no unique route has the required bandwidth. resources, e.g., no unique route has the required bandwidth.
o Fixed, member sharing: A fixed bandwidth VCG, transported over a Fixed, member sharing: A fixed bandwidth VCG, transported over a set
set of member signals that are allocated from a common pool of of member signals that are allocated from a common pool of
available member signals without requiring member connection available member signals without requiring member connection
teardown and setup. This document only covers the case where this teardown and setup. This document only covers the case where this
pool of "potential" member signals has been established via pool of "potential" member signals has been established via
mechanisms defined in this document. Note that by the nature of mechanisms defined in this document. Note that by the nature of
VCAT a member signal can only belong to one VCG at a time. To be VCAT, a member signal can only belong to one VCG at a time. To be
used in a different VCG a signal must first be removed from any used in a different VCG, a signal must first be removed from any
VCG to which it may belong. VCG to which it may belong.
o Dynamic, co-routed: A dynamic VCG (bandwidth can be increased or 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. The intent here is transported over a co-routed set of members. The application here
dynamic resizing and resilience of bandwidth. is dynamic resizing and resilience of bandwidth.
o Dynamic, diversely routed: A dynamic VCG (bandwidth can be Dynamic, diversely routed: A dynamic VCG (bandwidth can be increased
increased or decreased via the addition or removal of member or decreased via the addition or removal of member signals),
signals), transported over at least two diversely routed subsets transported over at least two diversely routed subsets of member
of member signals. The intent here is efficient use of network signals. The application here is efficient use of network
resources, dynamic resizing and resilience of bandwidth. resources, dynamic resizing and resilience of bandwidth.
o Dynamic, member sharing: A dynamic bandwidth VCG, transported over Dynamic, member sharing: A dynamic bandwidth VCG, transported over a
a set of member signals that are allocated from a common pool of set of member signals that are allocated from a common pool of
available member signals without requiring member connection available member signals without requiring member connection
teardown and setup. teardown and setup.
2.3. VCAT Operation With or Without LCAS 2.3. 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 in the provisioning of
but in the absence of LCAS, VCAT is still a valid technique. services, but in the absence of LCAS, VCAT is still a valid
Therefore GMPLS mechanisms for the operation of VCAT are REQUIRED for technique. Therefore GMPLS mechanisms for the operation of VCAT are
both the case where LCAS is available and the case where it is not REQUIRED for both the case where LCAS is available and the case where
available. The GMPLS procedures for the two cases SHOULD be it is not available. The GMPLS procedures for the two cases SHOULD
identical. be identical.
o GMPLS signaling for LCAS-capable interfaces MUST support all . GMPLS signaling for LCAS-capable interfaces MUST support all
scenarios of section 2.2. with no loss of traffic. scenarios of section 2.2. with no loss of traffic.
o GMPLS signaling for non-LCAS-capable interfaces MUST support only . GMPLS signaling for non-LCAS-capable interfaces MUST support
the "fixed" scenarios of section 2.2. only the "fixed" scenarios of section 2.2.
To provide for these requirements GMPLS signaling MUST carry the To provide for these requirements, GMPLS signaling MUST carry the
following information on behalf of the VCAT endpoints: following information on behalf of the VCAT endpoints:
oThe type of the member signal that the VCG will contain, e.g., . The type of the member signal that the VCG will contain, e.g.,
VC-3, VC-4, etc. VC-3, VC-4, etc.
oThe total number of members to be in the VCG. This provides the . The total number of members to be in the VCG. This provides the
endpoints in both the LCAS and non-LCAS case with information endpoints in both the LCAS and non-LCAS case with information on
on which to accept or reject the request, and in the non-LCAS which to accept or reject the request, and in the non-LCAS case
case will let the receiving endpoint know when all members of will let the receiving endpoint know when all members of the VCG
the VCG have been established. have been established.
oIdentification of the VCG and its associated members. This . Identification of the VCG and its associated members. This
provides information that allows the endpoints to provides information that allows the endpoints to differentiate
differentiate multiple VCGs and to tell what members (LSPs) multiple VCGs and to tell what members (LSPs) to associate with
to associate with a particular VCG. a particular VCG.
2.4. VCGs and VCG Members 2.4. VCGs and VCG Members
o VCG members (server layer connections) may be set up prior to The signaling solution SHOULD provide a mechanism to support these
their use in a VCG. scenarios:
o VCG members (server layer connections) may exist after their . VCG members (server layer connections) may be set up prior to
corresponding VCG has been removed. their use in a VCG.
The signaling solution SHOULD provide a mechanism to support the . VCG members (server layer connections) may exist after their
previous scenarios. However, it is not required that arbitrarily corresponding VCG has been removed.
created server layer connections be supported in the above scenarios,
i.e., connections established without following the procedures of However, it is not required that any arbitrarily created server layer
this document. connection be supported in the above scenarios, i.e., connections
established without following the procedures of this document.
3. VCAT Data and Control Plane Concepts 3. VCAT Data and Control Plane Concepts
In the next two sections we describe the signaling mechanisms that When utilizing GMPLS with VCAT/LCAS, we use a number of control and
already exist in GMPLS using RSVP-TE [RFC3473] and [RFC4328], and the data plane concepts described below.
extensions needed to completely support the requirements of section
2.
When utilizing GMPLS with VCAT/LCAS we utilize a number of control VCG -- This is the group of data plane server layer signals used to
and data plane concepts that we describe below. provide the bandwidth.
1. VCG member -- This is an individual data plane signal of one of the VCG member -- This is an individual data plane signal of one of the
permitted SDH, SONET, OTN or PDH signal types. permitted SDH, SONET, OTN or PDH signal types.
2. Co-signaled member set -- One or more VCG members (or potential Co-signaled set -- One or more VCG members (or potential members) set
members) set up via the same control plane signaling exchange. Note up via the same control plane signaling exchange. Note that all
that all members in a co-signaled set follow the same route. members in a co-signaled set follow the same route.
3. Co-routed member set - One or more VCG members that follow the same Co-routed set - One or more VCG members that follow the same route.
route. Although VCG members may follow the same path, this does not Although VCG members may follow the same path, this does not imply
imply that they were co-signaled. that they were co-signaled.
4. Data plane LSP -- for our purposes here, this is equivalent to an Data plane LSP -- This is an individual VCG member.
individual VCG member.
5. Control plane LSP -- A control plane entity that can control Control plane LSP -- A control plane entity that can control multiple
multiple data plane LSPs. For our purposes here this is equivalent data plane LSPs. For our purposes here, this is equivalent to the
to our co-signaled member set. co-signaled member set.
Section 4. is included for informational purposes only. It describes Call - A control plane mechanism for providing association between
existing GMPLS procedures that support a single VCG composed of a endpoints and possibly key transit points.
single co-signaled member set.
Section 5. describes new procedures to support VCGs composed of more 4. VCGs Composed of a Single Co-Signaled Member Set
than one co-signaled member sets. This includes the important
application of a VCG composed of diversely routed members. Where
possible it reuses applicable existing procedures from section 4.
4. VCGs Composed of a Single Co-Signaled Member Set (One LSP) In this section and the next section, we will describe the procedures
for supporting the applications described in Section 2.
This section describes the support of a single VCG composed of a
single co-signaled member set (in support of the fixed, co-routed
application and the dynamic, co-routed application) using existing
GMPLS procedures [RFC4606]. Note that this section is included for
informational purposes only.
The existing GMPLS signaling protocols support a VCG composed of a The existing GMPLS signaling protocols support a VCG composed of a
single co-signaled member set. Setup using the NVC field is explained single co-signaled member set. Setup using the NVC field is explained
in section 2.1 of [RFC4606]. In this case, one (single) control in section 2.1 of [RFC4606]. In this case, one (single) control
plane LSP is used in support of the VCG. As such, this section does plane LSP is used in support of the VCG.
not define or modify and procedures and is only included for
informative purposes.
There are two options for setting up the VCG, depending on hardware There are two options for setting up the VCG, depending on hardware
capability, or management preferences: one-shot setup and incremental capability or management preferences: one-shot setup and incremental
setup. 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 VC-4-7v 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) which is composed of 7 virtually concatenated VC-4s
(or STS-3c).
4.1. One-shot VCG Setup with Co-Signaled Members 4.1. One-shot VCG Setup with Co-Signaled Members
This section describes establishment of an LSP that supports all VCG An RSVP-TE Path message is used with the following parameters:
members as part of the initial LSP establishment. To establish such
and LSP, an RSVP-TE Path message is used with the following
parameters.
The traffic parameter's elementary signal is chosen (6 for VC-4/STS- . With regards to the traffic parameters, the elementary signal is
3c_SPE). The value of NVC is then set to 7. set to 6 (for VC-4/STS-3c_SPE). The value of NVC is then set to
7 (number of members).
SDH or SONET labels in turn have to be assigned for each member of . Per [RFC4606] a Multiplier Transform greater than 1 (say N>1) is
the VCG and concatenated to form a single Generalized Label used if the operator wants to set up N VCAT groups that will
constructed as an ordered list of 32-bit timeslot identifiers of the belong to, and be assigned to, the same LSP.
same format as TDM labels. [RFC4606] requires that the order of the
labels reflect the order of the payloads to concatenate, and not the . SDH or SONET labels in turn have to be assigned for each member
physical order of time-slots. of the VCG and concatenated to form a single Generalized Label
constructed as an ordered list of 32-bit timeslot identifiers of
the same format as TDM labels. [RFC4606] requires that the
order of the labels reflect the order of the payloads to
concatenate, and not the physical order of time-slots.
4.2. Incremental VCG Setup with Co-Signaled Members 4.2. Incremental VCG Setup with Co-Signaled Members
In some cases, it may be necessary or desirable to set up the VCG In some cases, it may be necessary or desirable to set up the VCG
members individually, or to add group members to an existing group. members individually, or to add group members to an existing group.
One example of this need is when the hardware that supports VCAT can One example of this need is when the hardware that supports VCAT can
only add VCAT elements one at a time or cannot automatically match only add VCAT elements one at a time or cannot automatically match
the elements at the ingress and egress for the purposes of inverse the elements at the ingress and egress for the purposes of inverse
multiplexing. Serial or incremental setup solves this problem. multiplexing. Serial or incremental setup solves this problem.
In order to accomplish incremental setup an iterative process is used In order to accomplish incremental setup, an iterative process is
to add group members. For each iteration, NVC is incremented up to used to add group members. For each iteration, NVC is incremented up
the final value required. The iteration consists of the successful to the final value required. A successful iteration consists of the
completion of Path and Resv signaling. At first, NVC = 1 and the successful completion of Path and Resv signaling. At first, NVC = 1
label includes just one timeslot identifier and the label includes just one timeslot identifier
At each of the next iterations, NVC is set to (NVC +1), one more At each of the next iterations, NVC is set to (NVC +1), one more
timeslot identifier is added to the ordered list in the Generalized timeslot identifier is added to the ordered list in the Generalized
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 (identifying the new member)
in-band to add the new label into the existing VCAT group. LCAS to the LSP, in the data plane, LCAS may be used to add the new member
signaling for this function is described in [ITU-T-G.7042]. into the existing VCAT group. LCAS (data plane) signaling is
described in [ITU-T-G.7042].
4.3. Procedure for VCG Reduction by Removing a Member 4.3. Procedure for VCG Reduction by Removing a Member
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. In the data plane,
signaling step is taken first to take the component out of service LCAS signaling is used first to take the component out of service
from the group. LCAS signaling is described in [ITU-T-G.7042]. from the group. 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 identifier for the dropped component is removed from the ordered
list in the Generalized Label. list in the Generalized Label.
Note that for interfaces that are not LCAS-capable, 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 data plane errors and result in
multiplexing procedure of VCAT and result in the teardown of the the teardown (failure) of the whole group. So, this is a feature
whole group. So, this is a feature that only LCAS-capable VCAT that only LCAS-capable VCAT interfaces can support without management
interfaces can support without management intervention at the end intervention at the end points.
points.
Note also that a VCG member can be temporary removed from the VCG due Note also that a VCG member can be temporary removed from the VCG due
to a failure of the component signal. The LCAS in-band signaling will to a failure of the component signal. The LCAS data plane signaling
take appropriate actions to adjust the VCG as described in [ITU-T- will take appropriate actions to adjust the VCG as described in [ITU-
G.7042]. T-G.7042].
4.4. Removing Multiple VCG Members in One Shot 4.4. Removing Multiple VCG Members in One Shot
The procedure is similar to 4.3. In this case, the NVC value is The procedure is similar to 4.3. 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 procedure is also not supported for the Generalized Label. This procedure is also not supported for
VCAT-only interfaces without management intervention as removing one VCAT-only interfaces without management intervention as removing one
or more components of the VCG will tear down the whole group. or more components of the VCG will tear down the whole group.
skipping to change at page 10, line 22 skipping to change at page 10, line 32
illustrates these relationships, however, note, VCAT calls can exist illustrates these relationships, however, note, VCAT calls can exist
independently of a VCG (for connection pre-establishment) as will be independently of a VCG (for connection pre-establishment) as will be
described later in this document. described later in this document.
+-------+ +-------------+ +-------+ +------------+ +-------+ +-------------+ +-------+ +------------+
| |1 n| |1 n| |1 n| Data Plane | | |1 n| |1 n| |1 n| Data Plane |
| VCG |<>----| VCAT Call |<>----| LSP |<>----| Connection | | VCG |<>----| VCAT Call |<>----| LSP |<>----| Connection |
| | | | | | |(co-routed) | | | | | | | |(co-routed) |
+-------+ +-------------+ +-------+ +------------+ +-------+ +-------------+ +-------+ +------------+
Figure 1 Figure 1. Conceptual containment relationship between VCG, Figure 1 Figure 1. Conceptual containment relationship between VCG,
VCAT calls, control plane LSPs, and data plane connections. VCAT calls, control plane LSPs, and data plane connections.
5.1. Signaled VCG Service Layer Information 5.1. Signaled VCG Service Layer Information
In this section, we provide a list of information that will be In this section, we provide a list of information that will be
communicated at the VCG level, i.e., between the VCG signaling communicated at the VCG level, i.e., between the VCG signaling
endpoints. When a VCG is composed of multiple co-signaled member endpoints. When a VCG is composed of multiple co-signaled member
sets, none of the individual LSP's control plane signaling sets, none of the individual LSP's control plane signaling
information can contain information pertinent to the entire VCG. To information can contain information pertinent to the entire VCG. To
accommodate this information, additional objects or TLVs are accommodate this information, additional objects or TLVs are
incorporated into the Notify message as it is described for use in incorporated into the Notify message as it is described for use in
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Max number of VCG members exceeded 4 Max number of VCG members exceeded 4
LSP Type incompatible with VCAT call 5 LSP Type incompatible with VCAT call 5
8. Security Considerations 8. Security Considerations
This document introduces a specific use of the Notify message and This document introduces a specific use of the Notify message and
admin status object for GMPLS signaling as originally specified in admin status object for GMPLS signaling as originally specified in
[RFC4974]. It does not introduce any new signaling messages, nor [RFC4974]. It does not introduce any new signaling messages, nor
change the relationship between LSRs that are adjacent in the control change the relationship between LSRs that are adjacent in the control
plane. The call information associated with diversely routed control plane. The call information associated with diversely routed control
plane LSPs, in the event of an interception may indicate that there plane LSPs, in the event of an interception, may indicate that these
are members of the same VCAT group that take a different route and are members of the same VCAT group that take a different route, and
may indicate to an interceptor that the VCG call desires increased may indicate to an interceptor that the VCG call desires increased
reliability. reliability.
Otherwise, this document does not introduce any additional security
considerations.
9. Contributors 9. Contributors
Wataru Imajuku (NTT) Wataru Imajuku (NTT)
1-1 Hikari-no-oka Yokosuka Kanagawa 239-0847 1-1 Hikari-no-oka Yokosuka Kanagawa 239-0847
Japan Japan
Phone +81-46-859-4315 Phone +81-46-859-4315
Email: imajuku.wataru@lab.ntt.co.jp Email: imajuku.wataru@lab.ntt.co.jp
Julien Meuric Julien Meuric
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