Network Working Group Z. Lin

Network Working Group Z. Lin
Request for Comments: 3474 New York City Transit
Category: Informational D. Pendarakis
Tellium
March 2003

Documentation of IANA assignments for
Generalized MultiProtocol Label Switching (GMPLS)
Resource Reservation Protocol - Traffic Engineering (RSVP-TE)
Usage and Extensions for
Automatically Switched Optical Network (ASON)

Status of this Memo

This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.

Copyright Notice

Copyright (C) The Internet Society (2003). All Rights Reserved.

Abstract

The Generalized MultiProtocol Label Switching (GMPLS) suite of
protocol specifications has been defined to provide support for
different technologies as well as different applications. These
include support for requesting TDM connections based on Synchronous
Optical NETwork/Synchronous Digital Hierarchy (SONET/SDH) as well as
Optical Transport Networks (OTNs).

This document concentrates on the signaling aspects of the GMPLS
suite of protocols, specifically GMPLS signaling using Resource
Reservation Protocol - Traffic Engineering (RSVP-TE). It proposes
additional extensions to these signaling protocols to support the
capabilities of an ASON network.

This document proposes appropriate extensions towards the resolution
of additional requirements identified and communicated by the ITU-T
Study Group 15 in support of ITU's ASON standardization effort.

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Table of Contents

1. Conventions used in this document...............................3
2. Introduction....................................................3
3. Support for Soft Permanent Connection...........................3
4. Support for Call................................................4
4.1 Call Identifier and Call Capability........................4
4.1.1 Call Identifier.....................................4
4.1.2 Call Capability.....................................7
4.2 What Does Current GMPLS Provide............................7
4.3 Support for Call and Connection............................7
4.3.1 Processing Rules....................................8
4.3.2 Modification to Path Message........................8
4.3.3 Modification to Resv Message........................9
4.3.4 Modification to PathTear Message....................9
4.3.5 Modification to PathErr Message....................10
4.3.6 Modification to Notify Message.....................10
5. Support For Behaviors during Control Plane Failures...........11
6. Support For Label Usage.......................................12
7. Support for UNI and E-NNI Signaling Session...................13
8. Additional Error Cases........................................14
9. Optional Extensions for Supporting
Complete Separation of Call and Connection....................15
9.1 Call Capability.........;.................................15
9.2 Complete Separation of Call and
Connection (RSVP-TE Extensions)...........................16
9.2.1 Modification to Path...............................16
9.2.2 Modification to Resv...............................17
9.2.3 Modification to PathTear...........................18
9.2.4 Modification to PathErr............................18
9.2.5 Modification to Notify.............................18
10. Security Considerations.......................................19
11. IANA Considerations...........................................19
11.1 Assignment of New Messages...............................19
11.2 Assignment of New Objects and Sub-Objects................19
11.3 Assignment of New C-Types................................20
11.4 Assignment of New Error Code/Values......................20
12. Acknowledgements..............................................20
13. References....................................................21
13.1 Normative References.....................................21
13.2 Informative References...................................22
14. Intellectual Property.........................................23
15. Contributors Contact Information..............................24
16. Authors' Addresses............................................24
17. Full Copyright Statement......................................25

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1. 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 BCP 14, RFC 2119
[RFC2119].

2. Introduction

This document contains the extensions to GMPLS for ASON-compliant
networks [G7713.2]. The requirements describing the need for these
extensions are provided in [GMPLS-ASON] as well as [ASON-RQTS].
These include:

- Support for call and connection separation
- Support for soft permanent connection
- Support for extended restart capabilities
- Additional error codes/values to support these extensions

This document concentrates on the signaling aspects of the GMPLS
suite of protocols, specifically GMPLS signaling using RSVP-TE. It
introduces extensions to GMPLS RSVP-TE to support the capabilities as
specified in the above referenced documents. Specifically, this
document uses the messages and objects defined by [RFC2205],
[RFC2961], [RFC3209], [RFC3471], [RFC3473], [OIF-UNI1] and [RFC3476]
as the basis for the GMPLS RSVP-TE protocol, with additional
extensions defined in this document.

3. Support for Soft Permanent Connection

In the scope of ASON, to support soft permanent connection (SPC) for
RSVP-TE, one new sub-type for the GENERALIZED_UNI object is defined.
The GENERALIZED_UNI object is defined in [RFC3476] and [OIF-UNI1].
This new sub-type has the same format and structure as the
EGRESS_LABEL (the sub-type is the suggested value for the new sub-
object):

- SPC_LABEL (Type=4, Sub-type=2)

The label association of the permanent ingress segment with the
switched segment at the switched connection ingress node is a local
policy matter (i.e., between the management system and the switched
connection ingress node) and is thus beyond the scope of this
document.

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The processing of the SPC_LABEL sub-object follows that of the
EGRESS_LABEL sub-object [OIF-UNI1]. Note that although the explicit
label control described in [RFC3471] and [RFC3473] may provide a
mechanism to support specifying the egress label in the context of
supporting the GMPLS application, the SPC services support for the
ASON model uses the GENERALIZED_UNI object for this extension to help
align the model for both switched connection and soft permanent
connection, as well as to use the service level and diversity
attributes of the GENERALIZED_UNI object.

4. Support for Call

To support basic call capability (logical call/connection
separation), a call identifier is introduced to the RSVP-TE message
sets. This basic call capability helps introduce the call model;
however, additional extensions may be needed to fully support the
canonical call model (complete call/connection separation).

4.1 Call Identifier and Call Capability

A Call identifier object is used in logical call/connection
separation while both the Call identifier object and a Call
capability object are used in complete call/connection separation.

4.1.1 Call Identifier

To identify a call, a new object is defined for RSVP-TE. The CALL_ID
object carries the call identifier. The value is globally unique
(the Class-num is the suggested value for the new object):

CALL_ID (Class-num = 230)

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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length |Class-Num (230)| C-Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Call identifier |
~ ... ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Where the following C-types are defined:

- C-Type = 1 (operator specific): The call identifier contains an
operator specific identifier.

- C-Type = 2 (globally unique): The call identifier contains a
globally unique part plus an operator specific identifier.

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The following structures are defined for the call identifier:

- Call identifier: generic [Length*8-32]-bit identifier. The number
of bits for a call identifier must be multiples of 32 bits, with a
minimum size of 32 bits.

The structure for the globally unique call identifier (to guarantee
global uniqueness) is to concatenate a globally unique fixed ID
(composed of country code, carrier code, unique access point code)
with an operator specific ID (where the operator specific ID is
composed of a source LSR address and a local identifier).

Therefore, a generic CALL_ID with global uniqueness includes <global
ID> (composed of <country code> plus <carrier code> plus <unique
access point code>) and <operator specific ID> (composed of <source
LSR address> plus <local identifier>). For a CALL_ID that only
requires operator specific uniqueness, only the <operator specific
ID> is needed, while for a CALL_ID that is required to be globally
unique, both <global ID> and <operator specific ID> are needed.

The <global ID> shall consist of a three-character International
Segment (the <country code>) and a twelve-character National Segment
(the <carrier code> plus <unique access point code>). These
characters shall be coded according to ITU-T Recommendation T.50. The
International Segment (IS) field provides a 3 character ISO 3166
Geographic/Political Country Code. The country code shall be based
on the three-character uppercase alphabetic ISO 3166 Country Code
(e.g., USA, FRA).

National Segment (NS):
The National Segment (NS) field consists of two sub-fields:

- the first subfield contains the ITU Carrier Code
- the second subfield contains a Unique Access Point Code.

The ITU Carrier Code is a code assigned to a network operator/service
provider, maintained by the ITU-T Telecommunication Service Bureauin
association with Recommendation M.1400. This code consists of 1-6
left-justified alphabetic, or leading alphabetic followed by numeric,
characters (bytes). If the code is less than 6 characters (bytes),
it is padded with a trailing NULL to fill the subfield.

The Unique Access Point Code is a matter for the organization to
which the country code and ITU carrier code have been assigned,
provided that uniqueness is guaranteed. This code consists of 1-6
characters (bytes), trailing NULL, completing the 12-character
National Segment. If the code is less than 6 characters, it is
padded by a trailing NULL to fill the subfield.

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Format of the National Segment

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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ITU carrier code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ITU carrie dode (cont) | Unique access point code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Unique access point code (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

The format of the Call identifier field for C-Type = 1:

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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length |Class-Num (230)| C-Type (1) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Resv |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source LSR address |
~ ... ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local identifier (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

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The format of the Call identifier field for C-Type = 2:

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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length |Class-Num (230)| C-Type (2) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | IS (3 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| NS (12 bytes) |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source LSR address |
~ ... ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local identifier (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

In both cases, a "Type" field is defined to indicate the type of
format used for the source LSR address. The Type field has the
following meaning:
For Type=0x01, the source LSR address is 4 bytes
For Type=0x02, the source LSR address is 16 bytes
For Type=0x03, the source LSR address is 20 bytes
For type=0x04, the source LSR address is 6 bytes
For type=0x7f, the source LSR address has the length defined by
the vendor

Source LSR address:
An address of the LSR controlled by the source network.

Local identifier:
A 64-bit identifier that remains constant over the life of
the call.

Note that if the source LSR address is assigned from an address space
that is globally unique, then the operator-specific CALL_ID may also
be used to represent a globally unique CALL_ID. However, this is not
guaranteed since the source LSR address may be assigned from an
operator-specific address space.

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4.1.2 Call Capability

The call capability feature is provided in Section 10. This is an
optional capability. If supported, section 10 extensions must be
followed.

4.2 What Does Current GMPLS Provide

The signaling mechanism defined in [RFC2961], [RFC3209] and [RFC3471]
supports automatic connection management; however it does not provide
capability to support the call model. A call may be viewed as a
special purpose connection that requires a different subset of
information to be carried by the messages. This information is
targeted to the call controller for the purpose of setting up a
call/connection association.

4.3 Support for Call and Connection

Within the context of this document, every call (during steady state)
may have one (or more) associated connections. A zero connection
call is defined as a transient state, e.g., during a break-before-
make restoration event.

In the scope of ASON, to support a logical call/connection
separation, a new call identifier is needed as described above. The
new GENERALIZED_UNI object is carried by the Path message. The new
CALL_ID object is carried by the Path, Resv, PathTear, PathErr, and
Notify messages. The ResvConf message is left unmodified. The
CALL_ID object (along with other objects associated with a call,
e.g., GENERALIZED_UNI) is processed by the call controller, while
other objects included in these messages are processed by the
connection controller as described in [RFC3473]. Processing of the
CALL_ID (and related) object is described in this document.

Note: unmodified RSVP message formats are not listed below.

4.3.1 Processing Rules

The following processing rules are applicable for call capability:

- For initial calls, the source user MUST set the CALL_ID's C-Type
and call identifier value to all-zeros.
- For a new call request, the first network node sets the
appropriate C-type and value for the CALL_ID.
- For an existing call (in case CALL_ID is non-zero) the first
network node verifies existence of the call.

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- The CALL_ID object on all messages MUST be sent from the ingress
call controller to egress call controller by all other
(intermediate) controllers without alteration. Indeed, the
Class-Num is chosen such that a node which does not support ASON
extensions to GMPLS forwards the object unmodified (value in the
range 11bbbbbb).
- The destination user/client receiving the request uses the CALL_ID
value as a reference to the requested call between the source user
and itself. Subsequent actions related to the call uses the
CALL_ID as the reference identifier.

4.3.2 Modification to Path Message

<Path Message> ::= <Common Header>
[ <INTEGRITY> ]
[ [<MESSAGE_ID_ACK> |
<MESSAGE_ID_NACK>] ... ]
[ <MESSAGE_ID> ]
<SESSION>
<RSVP_HOP>
<TIME_VALUES>
[ <EXPLICIT_ROUTE> ]
<LABEL_REQUEST>
[ <CALL_ID> ]
[ <PROTECTION> ]
[ <LABEL_SET> ... ]
[ <SESSION_ATTRIBUTE> ]
[ <NOTIFY_REQUEST> ]
[ <ADMIN_STATUS> ]
[ <GENERALIZED_UNI> ]
[ <POLICY_DATA> ... ]
<sender descriptor>

The format of the sender descriptor for unidirectional LSPs is not
modified by this document.

The format of the sender descriptor for bidirectional LSPs is not
modified by this document.

Note that although the GENERALIZED_UNI and CALL_ID objects are
optional for GMPLS signaling, these objects are mandatory for ASON-
compliant networks, i.e., the Path message MUST include both
GENERALIZED_UNI and CALL_ID objects.

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4.3.3 Modification to Resv Message

<Resv Message> ::= <Common Header>
[ <INTEGRITY> ]
[ [<MESSAGE_ID_ACK> |
<MESSAGE_ID_NACK>] ... ]
[ <MESSAGE_ID> ]
<SESSION>
<RSVP_HOP>
<TIME_VALUES>
[ <CALL_ID> ]
[ <RESV_CONFIRM> ]
<SCOPE>
[ <NOTIFY_REQUEST> ]
[ <ADMIN_STATUS> ]
[ <POLICY_DATA> ... ]
<STYLE>
<flow descriptor list>

<flow descriptor list> is not modified by this document.

Note that although the CALL_ID object is optional for GMPLS
signaling, this object is mandatory for ASON-compliant networks,
i.e., the Resv message MUST include the CALL_ID object.

4.3.4 Modification to PathTear Message

<PathTear Message> ::= <Common Header>
[ <INTEGRITY> ]
[ [<MESSAGE_ID_ACK> |
<MESSAGE_ID_NACK>] ... ]
[ <MESSAGE_ID> ]
<SESSION>
<RSVP_HOP>
[ <CALL_ID> ]
[ <sender descriptor> ]

<sender descriptor> ::= (see earlier definition)

Note that although the CALL_ID object is optional for GMPLS
signaling, this object is mandatory for ASON-compliant networks,
i.e., the PathTear message MUST include the CALL_ID object.

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4.3.5 Modification to PathErr Message

<PathErr Message> ::= <Common Header>
[ <INTEGRITY> ]
[ [<MESSAGE_ID_ACK> |
<MESSAGE_ID_NACK>] ... ]
[ <MESSAGE_ID> ]
<SESSION>
[ <CALL_ID> ]
<ERROR_SPEC>
[ <ACCEPTABLE_LABEL_SET> ]
[ <POLICY_DATA> ... ]
<sender descriptor>

<sender descriptor> ::= (see earlier definition)

Note that although the CALL_ID object is optional for GMPLS
signaling, this object is mandatory for ASON-compliant networks,
i.e., the PathErr message MUST include the CALL_ID object.

4.3.6 Modification to Notify Message

Note that this message may include sessions belonging to several
calls.

<Notify message> ::= <Common Header>
[<INTEGRITY>]
[ [<MESSAGE_ID_ACK> |
<MESSAGE_ID_NACK>] ... ]
[ <MESSAGE_ID> ]
<ERROR_SPEC>
<notify session list>

<notify session list> ::=
[ <notify session list> ]
<upstream notify session> |
<downstream notify session>

<upstream notify session> ::= <SESSION>
[ <CALL_ID> ]
[ <ADMIN_STATUS> ]
[<POLICY_DATA>...]
<sender descriptor>

<downstream notify session> ::= <SESSION>
[ <CALL_ID> ]
[<POLICY_DATA>...]
<flow descriptor list descriptor>

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Note that although the CALL_ID object is optional for GMPLS
signaling, this object is mandatory for ASON-compliant networks,
i.e., the Notify message MUST include the CALL_ID object.

5. Support For Behaviors during Control Plane Failures

Various types of control plane failures may occur within the network.
These failures may impact the control plane as well as the data plane
(e.g., in a SDH/SONET network if the control plane transport uses the
DCC and a fiber cut occurs, then both the control plane signaling
channel and the transport plane connection fails). As described in
[RFC3473], current GMPLS restart mechanisms allows support to handle
all of these different scenarios, and thus no additional extensions
are required.

In the scope of the ASON model, several procedures may take place in
order to support the following control plane behaviors (as per
[G7713] and [IPO-RQTS]):

- A control plane node SHOULD provide capability for persistent
storage of call and connection state information. This capability
allows each control plane node to recover the states of
calls/connections after recovery from a signaling controller
entity failure/reboot (or loss of local FSM state). Note that
although the restart mechanism allows neighbor control plane nodes
to automatically recover (and thus infer) the states of
calls/connections, this mechanism can also be used for
verification of neighbor states, while the persistent storage
provides the local recovery of lost state. In this case, per
[RFC3473], if during the Hello synchronization the restarting node
determines that a neighbor does not support state recovery (i.e.,
local state recovery only), and the restarting node maintains its
state on a per neighbor basis, the restarting node should
immediately consider the Recovery as completed.
- A control plane node detecting a failure of all control channels
between a pair of nodes SHOULD request an external controller
(e.g., the management system) for further instructions. The
default behavior is to enter into self-refresh mode (i.e.,
preservation) for the local call/connection states. As an
example, possible external instructions may be to remain in self-
refresh mode, or to release local states for certain connections.
Specific details are beyond the scope of this document.
- A control plane node detecting that one (or more) connections
cannot be re-synchronized with its neighbor (e.g., due to
different states for the call/connection) SHOULD request an
external controller (e.g., the management system) for further
instructions on how to handle the non-synchronized connection. As
an example, possible instructions may be to maintain the current

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local connection states. Specifics of the interactions between
the control plane and management plane are beyond the scope of
this document.
- A control plane node (after recovering from node failure) may lose
information on forwarding adjacencies. In this case the control
plane node SHOULD request an external controller (e.g., the
management system) for information to recover the forwarding
adjacency information. Specifics of the interactions between the
control plane and management plane are beyond the scope of this
document.

6. Support For Label Usage

Labels are defined in GMPLS to provide information on the resources
used for a particular connection. The labels may range from
specifying a particular timeslot, or a particular wavelength, to a
particular port/fiber. In the context of the automatic switched
optical network, the value of a label may not be consistently the
same across a link. For example, the figure below illustrates the
case where two GMPLS/ASON-enabled nodes (A and Z) are interconnected
across two non-GMPLS/ASON-enabled nodes (B and C; i.e., nodes B and C
do not support the ASON capability), where these nodes are all
SDH/SONET nodes providing, e.g., a VC-4 service.

+-----+ +-----+
| | +---+ +---+ | |
| A |---| B |---| C |---| Z |
| | +---+ +---+ | |
+-----+ +-----+

Labels have an associated structure imposed on them for local use
based on [GMPLS-SDHSONET] and [GMPLS-OTN]. Once the local label is
transmitted across an interface to its neighboring control plane
node, the structure of the local label may not be significant to the
neighbor node since the association between the local and the remote
label may not necessarily be the same. This issue does not present a
problem in a simple point-to-point connection between two control
plane-enabled nodes where the timeslots are mapped 1:1 across the
interface. However, in the scope of the ASON, once a non-GMPLS
capable sub-network is introduced between these nodes (as in the
above figure, where the sub-network provides re-arrangement
capability for the timeslots) label scoping may become an issue.

In this context, there is an implicit assumption that the data plane
connections between the GMPLS capable edges already exist prior to
any connection request. For instance node A's outgoing VC-4's
timeslot #1 (with SUKLM label=[1,0,0,0,0]) as defined in [GMPLS-
SONETSDH]) may be mapped onto node B's outgoing VC-4's timeslot #6

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(label=[6,0,0,0,0]) may be mapped onto node C's outgoing VC-4's
timeslot #4 (label=[4,0,0,0,0]). Thus by the time node Z receives
the request from node A with label=[1,0,0,0,0], the node Z's local
label and the timeslot no longer corresponds to the received label
and timeslot information.

As such to support the general case, the scope of the label value is
considered local to a control plane node. A label association
function can be used by the control plane node to map the received
(remote) label into a locally significant label. The information
necessary to allow mapping from a received label value to a locally
significant label value may be derived in several ways:

- Via manual provisioning of the label association
- Via discovery of the label association

Either method may be used. In the case of dynamic association, this
implies that the discovery mechanism operates at the timeslot/label
level before the connection request is processed at the ingress node.
Note that in the simple case where two nodes are directly connected,
no association may be necessary. In such instances, the label
association function provides a one-to-one mapping of the received
local label values.

7. Support for UNI and E-NNI Signaling Session

[RFC3476] defines a UNI IPv4 SESSION object used to support the UNI
signaling when IPv4 addressing is used. This document introduces
three new extensions. These extensions specify support for the IPv4
and IPv6 E-NNI session and IPv6 UNI session. These C-Types are
introduced to allow for easier identification of messages as regular
GMPLS messages, UNI messages, or E-NNI messages. This is
particularly useful if a single interface is used to support multiple
service requests.

Extensions to SESSION object (Class-num = 1):
- C-Type = 12: UNI_IPv6 SESSION object
- C-TYPE = 15: ENNI_IPv4 SESSION object
- C-Type = 16: ENNI_IPv6 SESSION object

The format of the SESSION object with C-Type = 15 is the same as that
for the SESSION object with C-Type = 7. The format of the SESSION
object with C-Type = 12 and 16 is the same as that for the SESSION
object with C-Type = 8.

The destination address field contains the address of the downstream
controller processing the message. For the case of the E-NNI
signaling interface (where eNNI-U represents the upstream controller

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and eNNI-D represents the downstream controller) the destination
address contains the address of eNNI-D. [OIF-UNI1] and [RFC3476]
describes the content of the address for UNI_IPv4 SESSION object,
which is also applicable for UNI_IPv6 SESSION object.

8. Additional Error Cases

In the scope of ASON, the following additional error cases are
defined:

- Policy control failure: unauthorized source; this error is
generated when the receiving node determines that a source
user/client initiated request for service is unauthorized based on
verification of the request (e.g., not part of a contracted
service). This is defined in [RFC3476].
- Policy control failure: unauthorized destination; this error is
generated when the receiving node determines that a destination
user/client is unauthorized to be connected with a source
user/client. This is defined in [RFC3476].
- Routing problem: diversity not available; this error is generated
when a receiving node determines that the requested diversity
cannot be provided (e.g., due to resource constraints). This is
defined in [RFC3476].
- Routing problem: service level not available; this error is
generated when a receiving node determines that the requested
service level cannot be provided (e.g., due to resource
constraints). This is defined in [RFC3476].
- Routing problem: invalid/unknown connection ID; this error is
generated when a receiving node determines that the connection ID
generated by the upstream node is not valid/unknown (e.g., does
not meet the uniqueness property). Connection ID is defined in
[OIF-UNI1].
- Routing problem: no route available toward source; this error is
generated when a receiving node determines that there is no
available route towards the source node (e.g., due to
unavailability of resources).
- Routing problem: unacceptable interface ID; this error is
generated when a receiving node determines that the interface ID
specified by the upstream node is unacceptable (e.g., due to
resource contention).
- Routing problem: invalid/unknown call ID; this error is generated
when a receiving node determines that the call ID generated by the
source user/client is invalid/unknown (e.g., does not meet the
uniqueness property).
- Routing problem: invalid SPC interface ID/label; this error is
generated when a receiving node determines that the SPC interface
ID (or label, or both interface ID and label) specified by the
upstream node is unacceptable (e.g., due to resource contention).

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9. Optional Extensions for Supporting Complete Separation of Call and
Connection

This section describes the optional and non-normative capability to
support complete separation of call and connection. To support
complete separation of call and connection, a call capability object
is introduced. The capability described in this Appendix is meant to
be an optional capability within the scope of the ASON specification.
An implementation of the extensions defined in this document include
support for complete separation of call and connection, defined in
this section.

9.1 Call Capability

A call capability is used to specify the capabilities supported for a
call. For RSVP-TE a new CALL_OPS object is defined to be carried by
the Path, Resv, PathTear, PathErr, and Notify messages. The CALL_OPS
object also serves to differentiate the messages to indicate a
"call-only" call. In the case for logical separation of call and
connection, the CALL_OPS object is not needed.

The CALL_OPS object is defined as follows (the Class-num is the
suggested value for the new object):

CALL_OPS (Class-num = 228, C-type = 1)

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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length |Class-Num (228)| C-Type (1) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Call ops flag |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Two flags are currently defined for the "call ops flag":
0x01: call without connection
0x02: synchronizing a call (for restart mechanism)

9.2 Complete Separation of Call and Connection (RSVP-TE Extensions)

A complete separation of call and connection implies that a call
(during steady state) may have zero (or more) associated connections.
A zero connection call is a steady state, e.g., simply setting up the
user end-point relationship prior to connection setup. The following
modified messages are used to set up a call. Set up of a connection
uses the messages defined in Section 5 above.

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9.2.1 Modification to Path

<Path Message> ::= <Common Header>
[ <INTEGRITY> ]
[ [<MESSAGE_ID_ACK> |
<MESSAGE_ID_NACK>] ... ]
[ <MESSAGE_ID> ]
<SESSION>
<RSVP_HOP>
<TIME_VALUES>
[ <EXPLICIT_ROUTE> ]
<LABEL_REQUEST>
<CALL_OPS>
<CALL_ID>
[ <NOTIFY_REQUEST> ]
[ <ADMIN_STATUS> ]
<GENERALIZED_UNI>
[ <POLICY_DATA> ... ]
<sender descriptor>

The format of the sender descriptor for unidirectional LSPs is:

<sender descriptor> ::= <SENDER_TEMPLATE>
<SENDER_TSPEC>
[ <RECORD_ROUTE> ]

The format of the sender descriptor for bidirectional LSPs is:

<sender descriptor> ::= <SENDER_TEMPLATE>
<SENDER_TSPEC>
[ <RECORD_ROUTE> ]
<UPSTREAM_LABEL>

Note that LABEL_REQUEST, SENDER_TSPEC and UPSTREAM_LABEL are not
required for a call; however these are mandatory objects. As such,
for backwards compatibility purposes, processing of these objects for
a call follows the following rules:

- These objects are ignored upon receipt; however, a valid-formatted
object (e.g., by using the received valid object in the
transmitted message) must be included in the generated message.

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9.2.2 Modification to Resv

<Resv Message> ::= <Common Header>
[ <INTEGRITY> ]
[ [<MESSAGE_ID_ACK> |
<MESSAGE_ID_NACK>] ... ]
[ <MESSAGE_ID> ]
<SESSION>
<RSVP_HOP>
<TIME_VALUES>
<CALL_OPS>
<CALL_ID>
[ <RESV_CONFIRM> ]
[ <NOTIFY_REQUEST> ]
[ <ADMIN_STATUS> ]
[ <POLICY_DATA> ... ]
<STYLE>
<flow descriptor list>

<flow descriptor list> ::=
<FF flow descriptor list>
| <SE flow descriptor>

<FF flow descriptor list> ::=
<FLOWSPEC>
<FILTER_SPEC>
[ <RECORD_ROUTE> ]
| <FF flow descriptor list>
<FF flow descriptor>
<FF flow descriptor> ::=
[ <FLOWSPEC> ]
<FILTER_SPEC>
[ <RECORD_ROUTE> ]

<SE flow descriptor> ::=
<FLOWSPEC>
<SE filter spec list>
<SE filter spec list> ::=
<SE filter spec>
| <SE filter spec list>
<SE filter spec>
<SE filter spec> ::=
<FILTER_SPEC>
[ <RECORD_ROUTE> ]

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Note that FILTER_SPEC and LABEL are not required for a call; however
these are mandatory objects. As such, for backwards compatibility
purposes, processing of these objects for a call follows the
following rules:

- These objects are ignored upon receipt; however, a valid-formatted
object (e.g., by using the received valid object in the
transmitted message) must be included in the generated message.

9.2.3 Modification to PathTear

<PathTear Message> ::= <Common Header>
[ <INTEGRITY> ]
[ [<MESSAGE_ID_ACK> |
<MESSAGE_ID_NACK>] ... ]
[ <MESSAGE_ID> ]
<SESSION>
<RSVP_HOP>
<CALL_OPS>
<CALL_ID>
[ <sender descriptor> ]

<sender descriptor> ::= (see earlier definition in this section)

9.2.4 Modification to PathErr

<PathErr Message> ::= <Common Header>
[ <INTEGRITY> ]
[ [<MESSAGE_ID_ACK> |
<MESSAGE_ID_NACK>] ... ]
[ <MESSAGE_ID> ]
<SESSION>
<CALL_OPS>
<CALL_ID>
<ERROR_SPEC>
[ <POLICY_DATA> ... ]
<sender descriptor>
<sender descriptor> ::= (see earlier definition in this section)

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9.2.5 Modification to Notify

<Notify message> ::= <Common Header>
[<INTEGRITY>]
[ [<MESSAGE_ID_ACK> |
<MESSAGE_ID_NACK>] ... ]
[ <MESSAGE_ID> ]
<ERROR_SPEC>
<notify session list>

<notify session list> ::=
[ <notify session list> ]
<upstream notify session> |
<downstream notify session>

<upstream notify session> ::= <SESSION>
<CALL_ID>
[ <ADMIN_STATUS> ]
[<POLICY_DATA>...]
<sender descriptor>

<downstream notify session> ::= <SESSION>
<CALL_ID>
[<POLICY_DATA>...]
<flow descriptor list descriptor>

10. Security Considerations

This document introduces no new security considerations.

11. IANA Considerations

There are multiple fields and values defined within this document.
IANA administers the assignment of these class numbers in the FCFS
space as shown in [see: http://www.iana.org/assignments/rsvp-
parameters].

11.1 Assignment of New Messages

No new messages are defined to support the functions discussed in
this document.

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11.2 Assignment of New Objects and Sub-Objects

Two new objects are defined:

- CALL_ID (ASON); this object should be assigned an object
identifier of the form 11bbbbbb. A suggested value is 230. Two C-
types are defined for this object
- C-Type = 1: Operator specific
- C-Type = 2: Globally unique

For the Type field, there is no range restriction, and the entire
range 0x00 to 0xff is open for assignment, with 0x00 to 0x7f
assignment based on FCFS and 0x80 to 0xff assignment reserved for
Private Use. The assignments are defined in this document:

- Type = 0x01: Source LSR address is 4-bytes
- Type = 0x02: Source LSR address is 16-bytes
- Type = 0x03: Source LSR address is 20-bytes
- Type = 0x04: Source LSR address is 6-bytes
- Type = 0x7f: the source LSR address has the length defined by the
vendor
- CALL_OPS (ASON); this object should be assigned an object
identifier of the form 11bbbbbb. The value is 228. One C-type is
defined for this object; the value is 1.

One new sub-object is defined under the GENERALIZED_UNI object:

- SPC_LABEL; this sub-object is part of the GENERALIZED_UNI object,
as a sub-type of the EGRESS_LABEL sub-object (which is Type=4).
The value is sub-type=2.

11.3 Assignment of New C-Types

Three new C-Types are defined for the SESSION object (Class-num = 1):

- C-Type = 12 (ASON): UNI_IPv6 SESSION object
- C-Type = 15 (ASON): ENNI_IPv4 SESSION object
- C-Type = 16 (ASON): ENNI_IPv6 SESSION object

11.4 Assignment of New Error Code/Values

No new error codes are required. The following new error values are
defined. Error code 24 is defined in [RFC3209].

24/103 (ASON): No route available toward source
24/104 (ASON): Unacceptable interface ID
24/105 (ASON): Invalid/unknown call ID
24/106 (ASON): Invalid SPC interface ID/label

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12. Acknowledgements

The authors would like to thank Osama Aboul-Magd, Jerry Ash, Sergio
Belotti, Greg Bernstein, Adrian Farrel, Nic Larkin, Lyndon Ong,
Dimitri Papadimitriou, Bala Rajagopalan, and Yangguang Xu for their
comments and contributions to the document.

13. References

13.1 Normative References

[G8080] ITU-T Rec. G.8080/Y.1304, Architecture for the
Automatically Switched Optical Network (ASON),
November 2001.

[G7713] ITU-T Rec. G.7713/Y.1704, Distributed Call and
Connection Management (DCM), November 2001.

[G7713.2] DCM Signalling Mechanisms Using GMPLS RSVP-TE, ITU-T
G.7713.2, January 2003.

[OIF-UNI1] UNI 1.0 Signaling Specification, The Optical
Internetworking Forum,
http://www.oiforum.com/public/UNI_1.0_ia.html

[RFC2026] Bradner, S., "The Internet Standards Process --
Revision 3", BCP 9, RFC 2026, October 1996.

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.

[RFC2205] Braden, R., Editor, Zhang, L., Berson, S., Herzog,
S. and S. Jamin, "Resource ReSerVation Protocol
(RSVP) -- Version 1 Functional Specification", RFC
2205, September 1997.

[RFC2961] Berger, L., Gan, D., Swallow, G., Pan, P., Tommasi,
F. and S. Molendini, "RSVP Refresh Overhead
Reduction Extensions", RFC 2961, April 2001.

[RFC3209] Awaduche, D., Berger, L., Gan, D., Li, T.,
Srinivasan, V. and G. Swallow, "RSVP-TE: Extensions
to RSVP for LSP Tunnels", RFC 3209, December 2001.

[RFC3471] Berger, L., Editor, "Generalized Multi-Protocol
Label Switching (MPLS) - Signaling Functional
Description", RFC 3471, January 2003.

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[RFC3473] Berger, L., Editor, "Generalized Multi-Protocol
Label Switching (MPLS) Signaling - Resource
ReserVation Protocol-Traffic Engineering (RSVP-TE)
Extensions", RFC 3473, January 2003.

[RFC3476] Rajagopalan, R., "Label Distribution Protocol (LDP)
and Resource ReserVation Protocol (RSVP) Extensions
for Optical UNI Signaling", RFC 3476, March 2003.

[ITU-LIAISE] http://www.ietf.org/IESG/LIAISON/ITU-OIF.html

13.2 Informative References

[G807] ITU-T Rec. G.807/Y.1301, Requirements For Automatic
Switched Transport Networks (ASTN), July 2001

[IPO-RQTS] Aboul-Magd, O., "Automatic Switched Optical Network
(ASON) Architecture and Its Related Protocols", Work
in Progress.

[GMPLS-ASON] Lin, Z., "Requirements for Generalized MPLS (GMPLS)
Usage and Extensions For Automatically Switched
Optical Network (ASON)", Work in Progress.

[ASON-RQTS] Xue, Y., "Carrier Optical Services Requirements",
Work in Progress.

[GMPLS-SDHSONET] Mannie, E., "GMPLS Extensions for SONET and SDH
Control", Work in Progress.

14. Intellectual Property

The IETF takes no position regarding the validity or scope of any
intellectual property or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on the
IETF's procedures with respect to rights in standards-track and
standards-related documentation can be found in RFC 2028. Copies of
claims of rights made available for publication and any assurances of
licenses to be made available, or the result of an attempt made to
obtain a general license or permission for the use of such
proprietary rights by implementors or users of this specification can
be obtained from the IETF Secretariat.

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The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive
Director.

15. Contributors Contact Information

Sergio Belotti
Alcatel
Via Trento 30,
I-20059 Vimercate, Italy
EMail: [email protected]

Nic Larkin
Data Connection
100 Church Street,
Enfield
Middlesex EN2 6BQ, UK
EMail: [email protected]

Dimitri Papadimitriou
Alcatel
Francis Wellesplein 1,
B-2018 Antwerpen, Belgium
EMail: [email protected]

Yangguang Xu
Lucent
1600 Osgood St, Room 21-2A41
North Andover, MA 01845-1043
EMail: [email protected]

16. Authors' Addresses

Zhi-Wei Lin
New York City Transit
2 Broadway, Room C3.25
New York, NY 10004

EMail: [email protected]

Dimitrios Pendarakis
Tellium
2 Crescent Place
Oceanport, NJ 07757-0901

EMail: [email protected]

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17. Full Copyright Statement

Copyright (C) The Internet Society (2003). All Rights Reserved.

This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.

The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.

This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Acknowledgement

Funding for the RFC Editor function is currently provided by the
Internet Society.

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