One document matched: draft-ietf-ccamp-gmpls-vcat-lcas-10.txt
Differences from draft-ietf-ccamp-gmpls-vcat-lcas-09.txt
CCAMP Working Group G. Bernstein (ed.)
Internet Draft Grotto Networking
Updates: RFC4606 D. Caviglia
Category: Standards Track Ericsson
Expires: January 2011 R. Rabbat
Google
H. van Helvoort
Huawei
July 12, 2010
Operating Virtual Concatenation (VCAT) and the Link Capacity
Adjustment Scheme (LCAS) with Generalized Multi-Protocol Label
Switching (GMPLS)
draft-ietf-ccamp-gmpls-vcat-lcas-10.txt
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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 the procedures for supporting virtual
concatenation in [RFC4606].
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 Co-Signaled Member Set...............7
4.1. One-shot 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
4.4. Removing Multiple VCG Members in One Shot.................9
4.5. Teardown of Whole VCG.....................................9
5. VCGs Composed of Multiple Co-Signaled Member Sets(Multiple LSPs)9
5.1. Signaled VCG Service Layer Information...................10
5.2. VCAT TLV.................................................11
5.3. Procedures for Multiple Co-signaled Member Sets..........13
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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
5.3.3. Associating an existing VCAT call with a new VCG....14
5.3.4. Removing the association between a call and VCG.....14
5.3.5. VCG Bandwidth modification..........................14
6. Error Conditions and Codes....................................15
7. IANA Considerations...........................................16
7.1. RSVP CALL_ATTRIBUTE TLV..................................16
7.2. RSVP Error Codes and Error Values........................16
8. Security Considerations.......................................17
9. Contributors..................................................18
10. Acknowledgments..............................................18
11. References...................................................19
11.1. Normative References....................................19
11.2. Informative References..................................19
Author's Addresses...............................................20
Intellectual Property Statement..................................21
Disclaimer of Validity...........................................21
Acknowledgment...................................................21
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 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 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
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where a subset of member signals are controlled by a management plane
or a proprietary control plane are beyond 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 LSR can be ingress/egress of one or more VCAT groups.
VCAT and LCAS are 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.
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.
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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. 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
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 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
only 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.
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. 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 (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.
VCG -- This is the group of data plane server layer signals used to
provide the bandwidth.
VCG member -- This is an individual data plane signal of one of the
permitted SDH, SONET, OTN or PDH signal types.
Co-signaled set -- One or more VCG members (or potential members) set
up via the same control plane signaling exchange. Note that all
members in a co-signaled set follow the same route.
Co-routed set - One or more VCG members that follow the same route.
Although VCG members may follow the same path, this does not imply
that they were co-signaled.
Data plane LSP -- This is an individual VCG member.
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Control plane LSP -- A control plane entity that can control multiple
data plane LSPs. For our purposes here, this is equivalent to the
co-signaled member set.
Call - A control plane mechanism for providing association between
endpoints and possibly key transit points.
4. VCGs Composed of a Single Co-Signaled Member Set
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
single co-signaled member set. Setup using the 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 hardware
capability or management 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
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
An RSVP-TE Path message is used with the following parameters:
. With regards to the traffic parameters, the elementary signal is
set to 6 (for VC-4/STS-3c_SPE). The value of NVC is then set to
7 (number of members).
. Per [RFC4606] a Multiplier Transform greater than 1 (say N>1) is
used if the operator wants to set up N VCAT groups that will
belong to, and be assigned to, the same LSP.
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. SDH or SONET labels in turn 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.
4.2. Incremental VCG Setup with Co-Signaled Members
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 hardware that supports VCAT can
only add VCAT elements one at a time or cannot automatically match
the elements 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
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
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 4.1.2. 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.
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Note that for interfaces that are not LCAS-capable, removing one
component of the VCG will result in data plane errors and result in
the teardown (failure) of the whole group. So, this is a feature
that only LCAS-capable VCAT interfaces can support without management
intervention at the end points.
Note also that a VCG member can be temporary 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].
5. VCGs Composed of Multiple Co-Signaled Member Sets(Multiple LSPs)
The motivation for VCGs composed of multiple co-signaled 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. In fact, [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 co-
signaled VCG member sets, i.e., multiple control plane LSPs.
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The support of a VCG with multiple co-signaled 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. This is provided by using the call procedures and extensions
described in [RFC4974]. The VCG is a higher layer service that 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.
In addition, by supporting the identification of a VCG and VCAT call
identification, 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.
+-------+ +-------------+ +-------+ +------------+
| |1 n| |1 n| |1 n| Data Plane |
| VCG |<>----| VCAT Call |<>----| LSP |<>----| Connection |
| | | | | | |(co-routed) |
+-------+ +-------------+ +-------+ +------------+
Figure 1 Figure 1. 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. When a VCG is composed of multiple co-signaled member
sets, none of the individual LSP's control plane signaling
information can contain information pertinent to the entire VCG. To
accommodate this information, additional objects or TLVs are
incorporated into the Notify message as it is described for use in
call signaling in [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].
VCG Call setup is signaled with a new CALL_ATTRIBUTES object TLV
containing the following information:
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1. Signal Type
2. Number of VCG Members
3. LCAS requirements:
a. LCAS required
b. LCAS desired
c. LCAS not desired (but acceptable)
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. VCAT TLV
In RFC4974 the general mechanisms and procedures for communicating
call information via Notify messages is defined. In [MLN-Ext] the
CALL_ATTRIBUTES object is defined for the conveyance of call related
information during call establishment and updates. We define a new
CALL_ATTRIBUTES object VCAT TLV for use in the CALL_ATTRIBUTES object
as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = TBA | Length = 12 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Signal Type | Number of Members |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LCAS Req | Action | VCG ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type, as defined in [MLN-Ext]. This field MUST be set to TBA (by
IANA).
Length, as defined in [MLN-Ext]. This field MUST be set to 12.
Signal Type: 16 bits
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]:
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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 OPU1 (i.e., 2.5 Gbit/s
12 OPU2 (i.e., 10 Gbit/s)
13 OPU3 (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.
LCAS Required: 8 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 desired (but acceptable)
Action: 8 bits
This field is used to indicate the relationship between the call
and the VCG and has the following values.
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Value Meaning
----- ---------------------------------
0 No VCG ID (set up call prior to VCG creation)
1 New VCG for Call
2 No Change in VCG ID (number of members may have changed)
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 Co-signaled Member Sets
The creation of a VCG based on multiple co-signaled member sets
requires the establishment of at least one VCAT layer call. VCAT
layer calls and related LSPs (connections) MUST follow the the
Procedures in Support of Calls and Connections 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 co-signaled 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.
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 MUST
be included 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
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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. 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. Note that signal types can never
be mixed in a VCG and hence a VCAT call contains only one signal
type.
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. The Notify
message is otherwise formatted and processed as defined under Call
Establishment in [RFC4974]. Note that the total number of VCGs
supported by a piece of equipment 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.
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.
The Notify message is otherwise formatted and processed as defined
under Call Establishment in [RFC4974].
5.3.5. VCG Bandwidth modification
The following cases may occur when increasing or decreasing the
bandwidth of a VCG:
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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 internal ordering SHOULD be used when modifying the
bandwidth of a VCG in a hitless fashion when LCAS is supported:
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. Any failures encountered in
processing these Notify messages are ignored.
2. Once the existing calls have successfully been notified of the
new number of members in the VCG, the bandwidth change can be made.
In the case of a decrease, the internal LCAS entity at the endpoints
MUST "deactivate" the VCG member(s). 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 an decrease.
In the case of an increase, after the bandwidth change is
successfully made, the internal LCAS entity at the endpoints MUST
"activate" the new VCG member(s).
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
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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
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.
We request that IANA make assignments from the CALL_ATTRIBUTES TLV
[MLN-Ext] portions of this registry.
This document introduces a new CALL_ATTRIBUTES TLV
TLV Value Name Reference
--------- ---------------------- ---------
TBD (2) 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)
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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
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.
Otherwise, this document does not introduce any additional security
considerations.
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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
[MLN-Ext] 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)",
work in progress: draft-ietf-ccamp-gmpls-mln-
extensions-09.txt, October, 2009.
[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.
[RFC4328] Papadimitriou, D., Ed., "Generalized Multi-Protocol
Label Switching (GMPLS) Signaling Extensions for G.709
Optical Transport Networks Control", RFC 4328, January
2006.
[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.
[ITU-T-G.7042] International Telecommunications Union, "Link Capacity
Adjustment Scheme (LCAS) for Virtual Concatenated
Signals", ITU-T Recommendation G.7042, March 2006.
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[ITU-T-G.7043] International Telecommunications Union, "Virtual
Concatenation of Plesiochronous Digital Hierarchy
(PDH) Signals", ITU-T Recommendation G.7043, July
2004.
[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.
Author's 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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