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Versions: (draft-bernstein-ccamp-gmpls-vcat-lcas)
00 01 02 03 04 05 06 07 08 09 10 11
12 13 RFC 6344
CCAMP Working Group G. Bernstein (ed.)
Internet Draft Grotto Networking
Updates: 4606 (if approved) D. Caviglia
Category: Standards Track Ericsson
Expires: November 2011 R. Rabbat
Google
H. van Helvoort
Huawei
May 4, 2011
Operating Virtual Concatenation (VCAT) and the Link Capacity
Adjustment Scheme (LCAS) with Generalized Multi-Protocol Label
Switching (GMPLS)
draft-ietf-ccamp-gmpls-vcat-lcas-13.txt
Status of this Memo
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Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Abstract
This document describes requirements for, and use of, the
Generalized Multi-Protocol Label Switching (GMPLS) control plane in
support of the Virtual Concatenation (VCAT) layer 1 inverse
multiplexing data plane mechanism and its companion Link Capacity
Adjustment Scheme (LCAS) which can be used for hitless dynamic
resizing of the inverse multiplex group. These techniques apply to
Optical Transport Network (OTN), Synchronous Optical Network
(SONET), Synchronous Digital Hierarchy (SDH), and Plesiochronous
Digital Hierarchy (PDH) signals. This document updates RFC 4606 by
making modifications to the procedures for supporting virtual
concatenation.
Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC-2119 [RFC2119].
Table of Contents
1. Introduction...................................................3
2. VCAT/LCAS Scenarios and Specific Requirements..................4
2.1. VCAT/LCAS Interface Capabilities..........................4
2.2. Member Signal Configuration Scenarios.....................4
2.3. VCAT Operation With or Without LCAS.......................5
2.4. VCGs and VCG Members......................................6
3. VCAT Data and Control Plane Concepts...........................6
4. VCGs Composed of a Single Member Set (One LSP).................7
4.1. One-shot VCG Setup........................................8
4.2. Incremental VCG Setup.....................................8
4.3. Procedure for VCG Reduction by Removing a Member..........9
4.4. Removing Multiple VCG Members in One Shot.................9
4.5. Teardown of Whole VCG.....................................9
5. VCGs Composed of Multiple Member Sets (Multiple LSPs).........10
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5.1. Signaled VCG Service Layer Information...................11
5.2. CALL ATTRIBUTES Object VCAT TLV..........................11
5.3. Procedures for Multiple Member Sets......................13
5.3.1. Setting up a new VCAT call and VCG Simultaneously...14
5.3.2. Setting up a VCAT call + LSPs without a 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.....15
5.3.5. VCG Bandwidth modification..........................15
6. Error Conditions and Codes....................................16
7. IANA Considerations...........................................16
7.1. RSVP CALL_ATTRIBUTE TLV..................................16
7.2. RSVP Error Codes and Error Values........................17
8. Security Considerations.......................................18
9. Contributors..................................................19
10. Acknowledgments..............................................19
11. References...................................................20
11.1. Normative References....................................20
11.2. Informative References..................................20
Authors' Addresses...............................................21
Intellectual Property Statement..................................22
Disclaimer of Validity...........................................22
Acknowledgment.........................Error! Bookmark not defined.
1. Introduction
The Generalized Multi-Protocol Label Switching (GMPLS) suite of
protocols allows for the automated control of different switching
technologies including Synchronous Optical Network (SONET)[ANSI-
T1.105], Synchronous Digital Hierarchy (SDH)[ITU-T-G.707], Optical
Transport Network (OTN)[ITU-T-G.709] and Plesiochronous Digital
Hierarchy (PDH)[ITU-T-G.704]. This document updates the procedures
of [RFC4606] to allow supporting additional applications of the
Virtual Concatenation (VCAT) layer 1 inverse multiplexing mechanism
that has 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].
VCAT is a time division multiplexing (TDM) oriented byte striping
inverse multiplexing method that works with a wide range of existing
and emerging TDM framed signals, including very high bit rate OTN
and SDH/SONET signals. VCAT enables the selection of an optimal
signal server bandwidth (size) utilizing a group of server signals
and provides for efficient use of bandwidth in a mesh network. When
combined with LCAS, hitless dynamic resizing of bandwidth and fast
graceful degradation in the presence of network faults can be
supported. To take full advantage of VCAT/LCAS functionality,
additional extensions to GMPLS signaling are needed that enable the
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setup of diversely routed signals that are members of the same VCAT
group. Note that the scope of this document is limited to scenarios
where all member signals of a VCAT group are controlled using
mechanisms defined in this document and related RFCs. Scenarios
where a subset of member signals are controlled by a management
plane or a proprietary control plane are outside the scope of this
document.
2. VCAT/LCAS Scenarios and Specific Requirements
There are a number of specific requirements for the support of
VCAT/LCAS in GMPLS that can be derived from the carriers'
applications for the use of VCAT/LCAS. These are set out in the
following section.
2.1. VCAT/LCAS Interface Capabilities
In general, an label switched router (LSR) can be ingress/egress of
one or more VCAT groups. VCAT and LCAS are data plane interface
capabilities. An LSR may have, for example, VCAT-capable interfaces
that are not LCAS-capable. It may at the same time have interfaces
that are neither VCAT nor LCAS-capable.
2.2. Member Signal Configuration Scenarios
We list in this section the different scenarios. Here we use the
[ITU-T-G.707] term "VCG" to refer to the VCAT group and the
terminology "set" and "subset" to refer to the subdivision of the
group and the individual VCAT group member signals. As noted above,
the scope of these scenarios is limited to scenarios where all
member signals are controlled using mechanisms defined in this
document.
The scenarios listed here are dependent on the terms "co-routed" and
"diversely routed". In the context of this document, "co-routed"
refers to a set of VCAT signals that all traverse the same sequence
of switching nodes. Furthermore, a co-routed set of signals between
any pair of adjacent nodes utilize a set of links that have similar
delay characteristics. Thus, "diversely routed" means a set of
signals that are not classed as "co-routed".
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Fixed, co-routed: A fixed bandwidth VCG, transported over a co-
routed set of member signals. This is the case where the
intended bandwidth of the VCG does not change and all member
signals follow the same route to minimize differential delay.
The application here is the capability to allocate an amount of
bandwidth close to that required at the client layer.
Fixed, diversely routed: A fixed bandwidth VCG, transported over at
least two diversely routed subsets of member signals. In this
case, the subsets are link-disjoint over at least one link of the
route. The application here is more efficient use of network
resources, e.g., no unique route has the required bandwidth.
Fixed, member sharing: A fixed bandwidth VCG, transported over a set
of member signals that are allocated from a common pool of
available member signals without requiring member connection
teardown and setup. This document only covers the case where this
pool of "potential" member signals has been established via
mechanisms defined in this document. Member signals need not be
co-routed or be guaranteed to be diversely routed. Note that by
the nature of 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 VCG to which it may belong.
Dynamic, co-routed: A dynamic VCG (bandwidth can be increased or
decreased via the addition or removal of member signals),
transported over a co-routed set of members. The application
here is dynamic resizing and resilience of bandwidth.
Dynamic, diversely routed: A dynamic VCG (bandwidth can be increased
or decreased via the addition or removal of member signals),
transported over at least two diversely routed subsets of member
signals. The application here is efficient use of network
resources, dynamic resizing and resilience of bandwidth.
Dynamic, member sharing: A dynamic bandwidth VCG, transported over a
set of member signals that are allocated from a common pool of
available member signals without requiring member connection
teardown and setup.
2.3. VCAT Operation With or Without LCAS
VCAT capabilities may be present with or without the presence of
LCAS. The use of LCAS is beneficial in the provisioning of flexible
bandwidth services, but in the absence of LCAS, VCAT is still a
valid technique. Therefore GMPLS mechanisms for the operation of
VCAT are REQUIRED for both the case where LCAS is available and the
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case where it is not available. The GMPLS procedures for the two
cases SHOULD be identical.
. GMPLS signaling for LCAS-capable interfaces MUST support all
scenarios of section 2.2. with no loss of traffic.
. GMPLS signaling for non-LCAS-capable interfaces MUST support
the "fixed" scenarios of section 2.2.
To provide for these requirements, GMPLS signaling MUST carry the
following information on behalf of the VCAT endpoints:
. The type of the member signal that the VCG will contain, e.g.,
VC-3, VC-4, etc.
. The total number of members to be in the VCG. This provides the
endpoints in both the LCAS and non-LCAS case with information on
which to accept or reject the request, and in the non-LCAS case
will let the receiving endpoint know when all members of the VCG
have been established.
. Identification of the VCG and its associated members. This
provides information that allows the endpoints to differentiate
multiple VCGs and to tell what members - label switched paths
(LSPs)- to associate with a particular VCG.
2.4. VCGs and VCG Members
The signaling solution SHOULD provide a mechanism to support these
scenarios:
. VCG members (server layer connections) may be set up prior to
their use in a VCG.
. VCG members (server layer connections) may exist after their
corresponding VCG has been removed.
However, it is not required that any arbitrarily created server
layer 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
When utilizing GMPLS with VCAT/LCAS, we use a number of control and
data plane concepts described below.
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VCG -- This is the group of data plane server layer signals used to
provide the bandwidth for the virtual concatenation link
connection through a network ([G7042]).
VCG member -- This is an individual data plane server layer signal
that belongs to a VCG ([G7042]).
Member set -- One or more VCG members (or potential members) set up
via the same control plane signaling exchange. Note that all
members in a member set follow the same route.
Data plane LSP -- This is an individual VCG member.
Control plane LSP -- A control plane entity that can control multiple
data plane LSPs. For our purposes here, this is equivalent to the
member set.
Call - A control plane mechanism for providing association between
endpoints and possibly key transit points.
4. VCGs Composed of a Single 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 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 and does not modify [RFC4606]. It is
provided to show how the existing GMPLS procedures may be used.
[RFC4606] provides the normative definition for GMPLS processing of
VCGs composed of a single member set, and in the event of any
conflict between this section and that document, [RFC4606] takes
precedence.
The existing GMPLS signaling protocols support a VCG composed of a
single member set. Setup using the number of virtual components
(NVC) field is explained in section 2.1 of [RFC4606]. In this case,
one (single) control plane LSP is used in support of the VCG.
There are two options for setting up the VCG, depending on policy
preferences: one-shot setup and incremental setup.
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
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SONET VCAT group) which is composed of 7 virtually concatenated VC-
4s (or STS-3c).
4.1. One-shot VCG Setup
This section describes establishment of an LSP that supports all VCG
members as part of the initial LSP establishment. To establish such
an LSP, an RSVP-TE Path message is sent containing the SONET/SDH
Traffic Parameters defined in [RFC4606]. In the case of this
example:
. Elementary signal is set to 6 (for VC-4/STS-3c_SPE).
. NVC is set to 7 (number of members).
. Per [RFC4606] a Multiplier Transform greater than 1 (say N>1)
may be used if the operator wants to set up N identical VCAT
groups (for the same LSP).
. SDH or SONET labels have to be assigned for each member 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.
. Refer to [RFC4606] for other traffic parameter settings.
4.2. Incremental VCG Setup
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.
One example of this need is when the local policy requires that VCAT
can only add VCAT members one at a time or cannot automatically
match the members at the ingress and egress for the purposes of
inverse multiplexing. Serial or incremental setup solves this
problem.
In order to accomplish incremental setup, an iterative process is
used to add group members. For each iteration, NVC is incremented
up to the final value required. A successful iteration consists of
the successful completion of Path and Resv signaling. At first, NVC
= 1 and the label includes just one timeslot identifier
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
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Label (in the Path or Resv message). A node that receives a 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
signal to the VCAT group, and switch the new timeslot based on the
new label information.
Following the addition of the new label (identifying the new member)
to the LSP, in the data plane, LCAS may be used to add the new
member at the end points 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
The procedure to remove a component signal is similar to that used
to add components as described in Section 4. 2. In the data plane,
LCAS signaling is used first to take the component out of service
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
identifier for the dropped component is removed from the ordered
list in the Generalized Label.
Note that for interfaces that are not LCAS-capable, removing one
component of the VCG will result in failure detection of the member
at the end point and failure of the whole group (per ITU-T
definition). So, this is a feature that only LCAS-capable VCAT
interfaces can support without management intervention at the end
points.
Note if using LCAS, a VCG member can be temporarily removed from the
VCG due to a failure of the component signal. The LCAS data plane
signaling will take appropriate actions to adjust the VCG as
described in [ITU-T-G.7042].
4.4. Removing Multiple VCG Members in One Shot
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
the components to be torn down are removed from the ordered list in
the Generalized Label. This procedure is also not supported for
VCAT-only interfaces without management intervention as removing one
or more components of the VCG will tear down the whole group.
4.5. Teardown of Whole VCG
The entire LSP is deleted in a single step (i.e., all components are
removed in one go) using deletion procedures of [RFC3473].
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5. VCGs Composed of Multiple Member Sets (Multiple LSPs)
The motivation for VCGs composed of multiple member sets comes from
the requirement to support VCGs with diversely routed members. The
initial GMPLS specification did not support diversely routed signals
using the NVC construct. [RFC4606] says:
[...] The standard definition for virtual concatenation allows
each virtual concatenation components to travel over diverse
paths. Within GMPLS, virtual concatenation components must
travel over the same (component) link if they are part of the
same LSP. This is due to the way that labels are bound to a
(component) link. Note however, that the routing of
components on different paths is indeed equivalent to
establishing different LSPs, each one having its own route.
Several LSPs can be initiated and terminated between the same
nodes and their corresponding components can then be
associated together (i.e., virtually concatenated).
The setup of diversely routed VCG members requires multiple VCG
member sets, i.e., multiple control plane LSPs.
The support of a VCG with multiple VCG members sets requires being
able to identify separate sets of control plane LSPs with a single
VCG and exchange information pertaining to the VCG as a whole
between the endpoints. This document updates the procedures of
[RFC4606] to provide this capability by using the call procedures
and extensions described in [RFC4974]. The VCG makes use of one or
more calls (VCAT calls) to associate control plane LSPs in support
of VCG server layer connections (VCG members) in the data plane.
Note, the trigger for the VCG (by management plane or client layer)
is outside the scope of this document. These procedures provide for
autonomy of the client layer and server layer with respect to their
management.
In addition, by supporting the identification of a VCG (VCG ID) and
VCAT call identification (VCAT Call ID), support can be provided for
the member sharing scenarios, i.e. by explicitly separating the VCG
ID from the VCAT call ID. Note that per [RFC4974], LSPs
(connections) cannot be moved from one call to another, hence to
support member sharing, the procedures in this document provide
support by moving call(s) and their associated LSPs from one VCG to
another. Figure 1 below illustrates these relationships, however,
note, VCAT calls can exist independently of a VCG (for connection
pre-establishment) as will be described later in this document.
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+-------+ +-------------+ +-------+ +------------+
| |1 n| |1 n| |1 n| Data Plane |
| VCG |<>----| VCAT Call |<>----| LSP |<>----| Connection |
| | | | | | |(co-routed) |
+-------+ +-------------+ +-------+ +------------+
. Conceptual containment relationship between VCG, VCAT
calls, control plane LSPs, and data plane connections.
5.1. Signaled VCG Service Layer Information
In this section, we provide a list of information that will be
communicated at the VCG level, i.e., between the VCG signaling
endpoints using the call procedures of [RFC4974]. To accommodate
the VCG information, a new TLV is defined in this document for the
CALL ATTRIBUTES Object [RFC6001] for use in the Notify message
[RFC4974]. The Notify message is a targeted message and does not
need to follow the path of LSPs through the network i.e. there is no
dependency on the member signaling for establishing the VCAT call
and does not preclude the use of external call managers as described
in [RFC4974].
The following information is needed:
1. Signal Type
2. Number of VCG Members
3. LCAS requirements:
a. LCAS required
b. LCAS desired
c. LCAS not supported
4. VCG Identifier - Used to identify a particular VCG separately
from the call ID so that call members can be reused with
different VCGs per the requirements for member sharing and the
requirements of section 2.4.
5.2. CALL ATTRIBUTES Object VCAT TLV
This document defines a CALL_ATTRIBUTES object VCAT TLV for use in
the CALL_ATTRIBUTES object [RFC6001] as follows:
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = TBA | Length = 12 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Signal Type | Number of Members |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|LCR| Reserved | Action | VCG ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type, as defined in [RFC6001]. This field MUST be set to TBA (by
IANA).
Length, as defined in [RFC6001]. This field MUST be set to 12.
Signal Type: 16 bits
The signal types can never be mixed in a VCG (per ITU-T
definition) and hence a VCAT call contains only one signal type.
This field can take the following values and MUST never change
over the lifetime of a VCG [ANSI-T1-105, ITU-T-G.707, ITU-T-G.709,
ITU-T-G.7043]:
Value Type (Elementary Signal)
----- ------------------------
1 VT1.5 SPE / VC-11
2 VT2 SPE / VC-12
3 STS-1 SPE / VC-3
4 STS-3c SPE / VC-4
11 ODU1 (i.e., 2.5 Gbit/s
12 ODU2 (i.e., 10 Gbit/s)
13 ODU3 (i.e., 40 Gbit/s)
21 T1 (i.e., 1.544 Mbps)
22 E1 (i.e., 2.048 Mbps)
23 E3 (i.e., 34.368 Mbps)
24 T3 (i.e., 44.736 Mbps)
Number of Members: 16 bits
This field is an unsigned integer that MUST indicate the total
number of members in the VCG (not just the call). This field MUST
be changed (over the life of the VCG) to indicate the current
number of members.
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LCR (LCAS Required): 2 bits
This field can take the following values and MUST NOT change over
the life of a VCG:
Value Meaning
----- ---------------------------------
0 LCAS required
1 LCAS desired
2 LCAS not supported
Action: 8 bits
This field is used to indicate the relationship between the call
and the VCG and has the following values.
Value Meaning
----- ---------------------------------
0 No VCG ID (set up call prior to VCG creation)
1 New VCG for Call
2 Modification of number of members (No Change in VCG ID)
3 Remove VCG from Call
VCG Identifier (ID): 16 bit
This field carries an unsigned integer that is used to identify a
particular VCG within a session. The value of the field MUST NOT
change over the lifetime of a VCG but MAY change over the lifetime
of a call.
5.3. Procedures for Multiple Member Sets
The creation of a VCG based on multiple member sets requires the
establishment of at least one VCAT layer call. VCAT layer calls and
related LSPs (connections) MUST follow the procedures as defined in
[RFC4974] with the addition of the inclusion of a CALL_ATTRIBUTES
object containing the VCAT TLV. Multiple VCAT layer calls per VCG
are not required to support member sets, but are needed to support
certain member sharing scenario.
The remainder of this section provides specific procedures related
to VCG signaling. The procedures of [RFC4974] are only modified as
discussed in this section.
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When LCAS is supported, the data plane will add or decrease the
members per [G7042]. When LCAS is not supported across LSPs, the
data plane coordination across member sets, is outside the scope of
this document.
5.3.1. Setting up a new VCAT call and VCG Simultaneously
To simultaneously set up a VCAT call and identify it with an
associated VCG, a CALL_ATTRIBUTES object containing the VCAT TLV
MUSTbe included in the Notify message at the time of call setup.
The VCAT TLV Action field MUST be set to 1, which indicates that
this is a new VCG for this call. LSPs MUST then be added to the
call until the number of members reaches the number specified in the
VCAT TLV.
5.3.2. Setting up a VCAT call + LSPs without a VCG
To provide for pre-establishment of the server layer connections for
a VCG a VCAT call MAY be established without an associated VCG
identifier. In fact, to provide for the member sharing scenario, a
pool of VCAT calls with associated connections (LSPs) can be
established, and then one or more of these calls (with accompanying
connections) can be associated with a particular VCG (via the VCG
ID). Note that multiple calls can be associated with a single VCG
but that a call MUST NOT contain members used in more than one VCG.
To establish a VCAT call with no VCG association, a CALL_ATTRIBUTES
object containing the VCAT TLV MUST be included at the time of call
setup in the Notify message. The VCAT TLV Action field MUST be set
to 0, which indicates that this is a VCAT call without an associated
VCG. LSPs can then be added to the call. The number of members
parameter in the VCAT TLV has no meaning at this point since it
reflects the intended number of members in a VCG and not in a call.
5.3.3. Associating an existing VCAT call with a new VCG
A VCAT call that is not otherwise associated with a VCG may be
associated with a VCG. To establish such an association a Notify
message MUST be sent with a CALL_ATTRIBUTES object containing a VCAT
TLV. The TLV's Action field MUST be set to 1, the VCG Identifier
field MUST be set to correspond to the VCG. The number of members
field MUST equal the sum of all LSPs associated with the VCG. Note
that the total number of VCGs supported by a node may be limited and
hence on reception of any message with a change of VCG ID this limit
should be checked. Likewise the sender of a message with a change in
VCG ID MUST be prepared to receive an error response. Again, any
error in a VCG may result in the failure of the complete VCG.
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5.3.4. Removing the association between a call and VCG
To reuse the server layer connections in a call in another VCG, the
current association between the call and a VCG MUST first be
removed. To do this, a Notify message MUST be sent with a
CALL_ATTRIBUTES object containing a VCAT TLV. The Action field of
the TLV MUST be set to 3 (Remove VCG from Call). The VCG ID field is
ignored and MAY be set to any value. The number of members field is
also ignored and MAY be set to any value. When the association
between a VCG and all existing calls has been removed then the VCG
is considered torn down.
5.3.5. VCG Bandwidth modification
The following cases may occur when increasing or decreasing the
bandwidth of a VCG:
1. LSPs are added to or, in the case of a decrease, removed from a
VCAT Call already associated with a VCG.
2. An existing VCAT call, and corresponding LSPs, is associated
with a VCG or, in the case of a decrease, has its association
removed. Note that in the increase case, the call MUST NOT have
any existing association with a VCG.
The following sequence SHOULD be used when modifying the bandwidth
of a VCG:
1. In both cases, prior to any other change, a Notify message MUST
be sent with a CALL_ATTRIBUTES object containing a VCAT TLV for each
of the existing VCAT calls associated with the VCG. The Action field
of the TLV MUST be set to 2. The VCG ID field MUST be set to match
the VCG. The number of members field MUST equal the sum of all LSPs
that are anticipated to be associated with the VCG after the
bandwidth change. The Notify message is otherwise formatted and
processed as defined under Call Establishment in [RFC4974]. If an
error is encountered while processing any of the Notify messages, the
number of members is reverted to the pre-change value and the
increase is aborted. The reverted number of members MUST be signaled
in a Notify message as described above. Failures encountered in
processing these Notify messages are handled per [RFC4974].
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2. Once the existing calls have successfully been notified of the
new number of members in the VCG, the bandwidth change can be made.
The next step is dependent on the two cases defined above. In the
first case defined above, the bandwidth change is made by adding (in
the case of increase) or removing (in the case of a decrease) LSPs
to the VCAT call per the procedures defined in [RFC4974]. In the
second case, the same procedure defined in Section 5.3.3. is
followed for an increase, and the procedure defined in Section
5.3.4. is followed for a decrease.
6. Error Conditions and Codes
VCAT Call and member LSP setup can be denied for various reasons. In
addition to the call procedures and related error codes described in
[RFC4974], below is a list of error conditions that can be
encountered during the procedures as defined in this document. These
fall under RSVP error code TBA.
These can occur when setting up a VCAT call or associating a VCG
with a VCAT call.
Error Value
------------------------------------ --------
VCG signal type not Supported 1
LCAS option not supported 2
Max number of VCGs exceeded 3
Max number of VCG members exceeded 4
LSP Type incompatible with VCAT call 5
Unknown LCR (LCAS required) value 6
Unknown or unsupported ACTION 7
Any failure in call or LSP establishment MUST be treated as a
failure of the VCG as a whole and MAY trigger the calls and LSPs
associated with the VCG being deleted.
7. IANA Considerations
7.1. RSVP CALL_ATTRIBUTE TLV
IANA has made the following assignments in the "Class Names, Class
Numbers, and Class Types" section of the "RSVP PARAMETERS" registry
located at http://www.iana.org/assignments/rsvp-parameters.
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We request that IANA make assignments from the CALL_ATTRIBUTES TLV
[RFC6001] portions of this registry.
This document introduces a new CALL_ATTRIBUTES TLV
TLV Value Name Reference
--------- ---------------------- ---------
TBD VCAT_TLV This I-D
7.2. RSVP Error Codes and Error Values
A new RSVP Error Code and new Error Values are introduced. We
request IANA make assignments from the "RSVP Parameters" registry
using the sub-registry "Error Codes and Globally-Defined Error Value
Sub-Codes".
o Error Codes:
- VCAT Call Management (value TBD)
o Error Values:
Meaning Value
------------------------------------ --------
VCG signal type not Supported 1
LCAS option not supported 2
Max number of VCGs exceeded 3
Max number of VCG members exceeded 4
LSP Type incompatible with VCAT call 5
Unknown LCR (LCAS required) value 6
Unknown or unsupported ACTION 7
7.3. VCAT Elementary Signal Registry
IANA is requested to create a registry to track elementary signal
types as defined in Section 5.2. New allocations are by "IETF
Review" [RFC5226].
IANA is requested to track:
- Value
- Type (Elementary Signal)
- RFC
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The available range is 0 - 65535
The registry should be initially populated with the values shown in
Section 5.2 of this document. Value 0 should be marked as Reserved.
Other values should be marked Unassigned.
7.4. VCAT VCG Operation Actions
IANA is requested to create a registry to track VCAT VCG operation
actions as defined in Section 5.2. New allocations are by "IETF
Review" [RFC5226].
IANA is requested to track:
- Value
- Meaning
- RFC
The available range is 0 - 255
The registry should be initially populated with the values shown in
Section 5.2 of this document. Other values should be marked
Unassigned.
8. Security Considerations
This document introduces a specific use of the Notify message and
admin status object for GMPLS signaling as originally specified in
[RFC4974]. It does not introduce any new signaling messages, nor
change the relationship between LSRs that are adjacent in the
control plane. The call information associated with diversely
routed control 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 may indicate to an interceptor that the VCG
call desires increased reliability.
See [RFC5920] for additional information on GMPLS security.
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9. Contributors
Wataru Imajuku (NTT)
1-1 Hikari-no-oka Yokosuka Kanagawa 239-0847
Japan
Phone +81-46-859-4315
Email: imajuku.wataru@lab.ntt.co.jp
Julien Meuric
France Telecom
2, avenue Pierre Marzin
22307 Lannion Cedex
France
Phone: + 33 2 96 05 28 28
Email: julien.meuric@orange-ft.com
Lyndon Ong
Ciena
PO Box 308
Cupertino, CA 95015
United States of America
Phone: +1 408 705 2978
Email: lyong@ciena.com
10. Acknowledgments
The authors would like to thank Adrian Farrel, Maarten Vissers,
Trevor Wilson, Evelyne Roch, Vijay Pandian, Fred Gruman, Dan Li,
Stephen Shew, Jonathan Saddler and Dieter Beller for extensive
reviews and contributions to this draft.
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11. References
11.1. Normative References
[RFC6001] Papadimitriou, D., Vigoureux M., Shiomoto, K.
Brungard, D., Le Roux, JL., "Generalized Multi-
Protocol Label Switching (GMPLS) Protocol Extensions
for Multi-Layer and Multi-Region Networks (MLN/MRN)",
October, 2010.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3473] Berger, L., "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Resource ReserVation
Protocol-Traffic Engineering (RSVP-TE) Extensions",
RFC 3473, January 2003.
[RFC4606] Mannie, E. and D. Papadimitriou, "Generalized Multi-
Protocol Label Switching (GMPLS) Extensions for
Synchronous Optical Network (SONET) and Synchronous
Digital Hierarchy (SDH) Control", RFC 4606, December
2005.
[RFC4974] Papadimitriou, D. and A. Farrel, "Generalized MPLS
(GMPLS) RSVP-TE Signaling Extensions in Support of
Calls", RFC 4974, August 2007.
11.2. Informative References
[ANSI-T1.105] American National Standards Institute, "Synchronous
Optical Network (SONET) - Basic Description including
Multiplex Structure, Rates, and Formats", ANSI
T1.105-2001, May 2001.
[G7042] International Telecommunications Union, "Link
Capacity Adjustment Scheme (LCAS) for Virtual
Concatenated Signals", ITU-T Recommendation G.7042,
March 2006.
[ITU-T-G.7043] International Telecommunications Union, "Virtual
Concatenation of Plesiochronous Digital Hierarchy
(PDH) Signals", ITU-T Recommendation G.7043, July
2004.
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[ITU-T-G.704] International Telecommunications Union, " Synchronous
frame structures used at 1544, 6312, 2048, 8448 and
44 736 kbit/s hierarchical levels", ITU-T
Recommendation G.704, October 1998.
[ITU-T-G.707] International Telecommunications Union, "Network Node
Interface for the Synchronous Digital Hierarchy
(SDH)", ITU-T Recommendation G.707, December 2003.
[ITU-T-G.709] International Telecommunications Union, "Interfaces
for the Optical Transport Network (OTN)", ITU-T
Recommendation G.709, March 2003.
[RFC5920] L. Fang, Ed., "Security Framework for MPLS and GMPLS
Networks", July 2010.
[RFC5226] T. Narten, H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", May 2008.
Authors' Addresses
Greg M. Bernstein (ed.)
Grotto Networking
Fremont California, USA
Phone: (510) 573-2237
Email: gregb@grotto-networking.com
Diego Caviglia
Ericsson
Via A. Negrone 1/A 16153
Genoa Italy
Phone: +39 010 600 3736
Email: diego.caviglia@(marconi.com, ericsson.com)
Richard Rabbat
Google, Inc.
1600 Amphitheatre Parkway
Mountain View, CA 94043, USA
Email: rabbat@alum.mit.edu
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Huub van Helvoort
Huawei Technologies, Ltd.
Kolkgriend 38, 1356 BC Almere
The Netherlands
Phone: +31 36 5315076
Email: hhelvoort@huawei.com
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