draft-ietf-ccamp-gmpls-ason-reqts-06.txt   draft-ietf-ccamp-gmpls-ason-reqts-07.txt 
CCAMP Working Group D. Papadimitriou (Alcatel)
Network Working Group D. Papadimitriou (Alcatel)
Internet Draft J. Drake (Calient) Internet Draft J. Drake (Calient)
Category: Informational J. Ash (ATT) Category: Informational J. Ash (ATT)
A. Farrel (Old Dog Consulting) Expiration Date: April 2005 A. Farrel (Old Dog Consulting)
Expiration Date: October 2004 L. Ong (Ciena) L. Ong (Ciena)
April 2004 October 2004
Requirements for Generalized MPLS (GMPLS) Signaling Usage Requirements for Generalized MPLS (GMPLS) Signaling Usage
and Extensions for Automatically Switched Optical Network (ASON) and Extensions for Automatically Switched Optical Network (ASON)
draft-ietf-ccamp-gmpls-ason-reqts-06.txt draft-ietf-ccamp-gmpls-ason-reqts-07.txt
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is subject to all provisions
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author represents that any applicable patent or other IPR claims of
which he or she is aware have been or will be disclosed, and any of
which he or she become aware will be disclosed, in accordance with
RFC 3668.
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1. Abstract Copyright Notice
The Generalized MPLS (GMPLS) suite of protocols has been defined to Copyright (C) The Internet Society (2004). All Rights Reserved.
control different switching technologies as well as different
applications. These include support for requesting TDM connections Abstract
including SONET/SDH and Optical Transport Networks (OTNs).
The Generalized Multi-Protocol Label Switching (GMPLS) suite of
protocols has been defined to control different switching
technologies as well as different applications. These include support
for requesting Time Division Multiplexing (TDM) connections including
Synchronous Optical Network (SONET)/Synchronous Digital Hierarchy
(SDH) and Optical Transport Networks (OTNs).
D.Papadimitriou et al. - Expires April 2005 1
This document concentrates on the signaling aspects of the GMPLS This document concentrates on the signaling aspects of the GMPLS
suite of protocols. It identifies the features to be covered by the suite of protocols. It identifies the features to be covered by the
GMPLS signaling protocol to support the capabilities of an GMPLS signaling protocol to support the capabilities of an
Automatically Switched Optical Network (ASON). This document Automatically Switched Optical Network (ASON). This document provides
provides a problem statement and additional requirements on the a problem statement and additional requirements on the GMPLS
GMPLS signaling protocol to support the ASON functionality. signaling protocol to support the ASON functionality.
D.Papadimitriou et al. - Expires October 2004 1
2. Conventions used in this document 1. Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
this document are to be interpreted as described in [RFC 2119]. document are to be interpreted as described in [RFC2119].
3. Introduction While [RFC2119] describes interpretations of these key words in terms
of protocol specifications and implementations, they are used in this
document to describe design requirements for protocol extensions.
The GMPLS suite of protocol specifications provides support for 2. Introduction
controlling different switching technologies as well as different
applications. These include support for requesting TDM connections The Generalized Multi-Protocol Label Switching (GMPLS) suite of
including SONET/SDH (see ANSI T1.105 and ITU-T G.707, respectively) protocol specifications provides support for controlling different
as well as Optical Transport Networks (see ITU-T G.709). In switching technologies as well as different applications. These
addition, there are certain capabilities that are needed to support include support for requesting Time Division Multiplexing (TDM)
Automatically Switched Optical Networks control planes (their connections including Synchronous Optical Network (SONET)/Synchronous
architecture is defined in [ITU-T G.8080]). These include generic Digital Hierarchy (SDH) (see ANSI T1.105 and ITU-T G.707,
capabilities such as call and connection separation, and more respectively) as well as Optical Transport Networks (see ITU-T
G.709). In addition, there are certain capabilities that are needed
to support Automatically Switched Optical Networks control planes
(their architecture is defined in [ITU-T G.8080]). These include
generic capabilities such as call and connection separation, and more
specific capabilities such as support of soft permanent connections. specific capabilities such as support of soft permanent connections.
This document concentrates on requirements related to the signaling This document concentrates on requirements related to the signaling
aspects of the GMPLS suite of protocols. It discusses functional aspects of the GMPLS suite of protocols. It discusses functional
requirements required to support Automatically Switched Optical requirements required to support Automatically Switched Optical
Networks that MAY lead to additional extensions to GMPLS signaling Networks that may lead to additional extensions to GMPLS signaling
(see [RFC 3471] and [RFC 3473]) to support these capabilities. In (see [RFC 3471] and [RFC 3473]) to support these capabilities. In
addition to ASON signaling requirements, this document includes addition to ASON signaling requirements, this document includes GMPLS
GMPLS signaling requirements regarding backward compatibility signaling requirements regarding backward compatibility (Section 5).
(Section 5). A terminology section is provided in the Appendix. A terminology section is provided in the Appendix.
Problem Statement: 3. Problem Statement
The Automatically Switched Optical Network (ASON) architecture The Automatically Switched Optical Network (ASON) architecture
describes the application of an automated control plane for describes the application of an automated control plane for
supporting both call and connection management services (for a supporting both call and connection management services (for a
detailed description see [ITU-T G.8080]). The ASON architecture detailed description see [ITU-T G.8080]). The ASON architecture
describes a reference architecture, i.e. it describes functional describes a reference architecture, i.e. it describes functional
components, abstract interfaces, and interactions. components, abstract interfaces, and interactions.
The ASON model distinguishes reference points (representing points The ASON model distinguishes reference points (representing points of
of information exchange) defined (1) between a user (service information exchange) defined (1) between a user (service requester)
requester) and a service provider control domain a.k.a. user-network
interface (UNI), (2) between control domains a.k.a. external D.Papadimitriou et al. - Expires April 2005 2
network-network interface (E-NNI) and, (3) within a control domain and a service provider control domain a.k.a. user-network interface
a.k.a. internal network-network interface (I-NNI). The I-NNI and E- (UNI), (2) between control domains a.k.a. external network-network
NNI interfaces are between protocol controllers, and may or may not interface (E-NNI) and, (3) within a control domain a.k.a. internal
use transport plane (physical) links. It MUST NOT be assumed that network-network interface (I-NNI). The I-NNI and E-NNI interfaces are
there is a one-to-one relationship of control plane interfaces and between protocol controllers, and may or may not use transport plane
transport plane (physical) links, or that there is a one-to-one (physical) links. It must not be assumed that there is a one-to-one
relationship of control plane entities and transport plane entities, relationship of control plane interfaces and transport plane
or that there is a one-to-one relationship of control plane (physical) links, or that there is a one-to-one relationship of
identifiers for transport plane resources. control plane entities and transport plane entities, or that there is
a one-to-one relationship of control plane identifiers for transport
plane resources.
D.Papadimitriou et al. - Expires October 2004 2
This document describes requirements related to the use of GMPLS This document describes requirements related to the use of GMPLS
signaling (in particular, [RFC 3471] and [RFC 3473]) to provide call signaling (in particular, [RFC 3471] and [RFC 3473]) to provide call
and connection management (see [ITU-T G.7713]). The functionality to and connection management (see [ITU-T G.7713]). The functionality to
be supported includes: be supported includes:
(a) soft permanent connection capability (a) soft permanent connection capability
(b) call and connection separation (b) call and connection separation
(c) call segments (c) call segments
(d) extended restart capabilities during control plane failures (d) extended restart capabilities during control plane failures
(e) extended label association (e) extended label association
(f) crankback capability (f) crankback capability
(g) additional error cases. (g) additional error cases.
4. Requirements for Extending Applicability of GMPLS to ASON 4. Requirements for Extending Applicability of GMPLS to ASON
The next sections detail the signaling protocol requirements for The next sections detail the signaling protocol requirements for
GMPLS to support the ASON functions listed in Section 3. ASON GMPLS to support the ASON functions listed in Section 3. ASON defines
defines a reference model and functions (information elements) to a reference model and functions (information elements) to enable end-
enable end-to-end call and connection support by a protocol across to-end call and connection support by a protocol across the
the respective interfaces, regardless of the particular choice of respective interfaces, regardless of the particular choice of
protocol(s) used in a network. ASON does not restrict the use of protocol(s) used in a network. ASON does not restrict the use of
other protocols or the protocol-specific messages used to support other protocols or the protocol-specific messages used to support the
the ASON functions. Therefore, the support of these ASON functions ASON functions. Therefore, the support of these ASON functions by a
by a protocol shall not be restricted by (i.e. must be strictly protocol shall not be restricted by (i.e. must be strictly
independent of and agnostic to) any particular choice of UNI, I-NNI, independent of and agnostic to) any particular choice of UNI, I-NNI,
or E-NNI used elsewhere in the network. In order to allow for or E-NNI used elsewhere in the network. In order to allow for
interworking between different protocol implementations, [G.7713] interworking between different protocol implementations, [ITU-T
recognizes an interworking function may be needed. G.7713] recognizes an interworking function may be needed.
In support of the G.8080 end-to-end call model across different In support of the G.8080 end-to-end call model across different
control domains, end-to-end signaling should be facilitated control domains, end-to-end signaling should be facilitated
regardless of the administrative boundaries and protocols within the regardless of the administrative boundaries, protocols within the
network. This implies that there needs to be a clear mapping of ASON network or method of realization of connections within any part of
signaling requests between GMPLS control domains and non-GMPLS the network. This implies that there needs to be a clear mapping of
control domains. This document provides signalling requirements for ASON signaling requests between GMPLS control domains and non-GMPLS
control domains. This document provides signaling requirements for
G.8080 distributed call and connection management based on GMPLS, G.8080 distributed call and connection management based on GMPLS,
within a GMPLS based control domain (I-NNI) and between GMPLS based within a GMPLS based control domain (I-NNI) and between GMPLS based
control domains (E-NNI). It does not restrict use of other (non- control domains (E-NNI). It does not restrict use of other (non
GMPLS) protocols to be used within a control domain or as an E-NNI GMPLS) protocols to be used within a control domain or as an E-NNI or
or UNI. Interworking aspects related to the use of non-GMPLS UNI. Interworking aspects related to the use of non-GMPLS protocols
protocols as UNI, E-NNI, or I-NNI, including mapping of non-GMPLS
protocol signaling requests to corresponding ASON signaling D.Papadimitriou et al. - Expires April 2005 3
functionality and support of non-GMPLS address formats, is not as UNI, E-NNI, or I-NNI, including mapping of non-GMPLS protocol
within the scope of the GMPLS signaling protocol. Interworking signaling requests to corresponding ASON signaling functionality and
aspects are implementation-specific and strictly under the support of non-GMPLS address formats, is not within the scope of the
responsibility of the interworking function, and thus outside the GMPLS signaling protocol. Interworking aspects are implementation-
scope of this document. specific and strictly under the responsibility of the interworking
function, and thus outside the scope of this document.
Any User-Network Interface (UNI) that is compliant with [RFC 3473], Any User-Network Interface (UNI) that is compliant with [RFC 3473],
e.g. [GMPLS-OVERLAY] and [GMPLS-VPN] is considered, by definition, e.g. [GMPLS-OVERLAY] and [GMPLS-VPN] is considered, by definition, to
to be included within the GMPLS suite of protocols and must be be included within the GMPLS suite of protocols and MUST be supported
supported by the ASON GMPLS signaling functionality. by the ASON GMPLS signaling functionality.
D.Papadimitriou et al. - Expires October 2004 3
Compatibility aspects of non-GMPLS systems (nodes) within a GMPLS Compatibility aspects of non-GMPLS systems (nodes) within a GMPLS
control domain i.e. the support of GMPLS systems and other systems control domain i.e. the support of GMPLS systems and other systems
which utilize other signaling protocols or some which may not which utilize other signaling protocols or some which may not support
support any signaling protocols is described. For instance, Section any signaling protocols is described. For instance, Section 4.5
4.5 'Support for Extended Label Association' covers the requirements 'Support for Extended Label Association' covers the requirements when
when a non-GMPLS capable sub-network is introduced or when nodes do a non-GMPLS capable sub-network is introduced or when nodes do not
not support any signaling protocols. support any signaling protocols.
4.1 Support for Soft Permanent Connection (SPC) Capability 4.1 Support for Soft Permanent Connection (SPC) Capability
An SPC is a combination of a permanent connection at the source An SPC is a combination of a permanent connection at the source user-
user-to-network side, a permanent connection at the destination to-network side, a permanent connection at the destination user-to-
user-to-network side, and a switched connection within the network. network side, and a switched connection within the network. An
An Element Management System (EMS) or a Network Management System Element Management System (EMS) or a Network Management System (NMS)
(NMS) typically initiates the establishment of the switched typically initiates the establishment of the switched connection by
connection by communicating with the node that initiates the communicating with the node that initiates the switched connection
switched connection (also known as the ingress node). The latter (also known as the ingress node). The latter then sets the connection
then sets the connection using the distributed GMPLS signaling using the distributed GMPLS signaling protocol. For the SPC, the
protocol. For the SPC, the communication method between the EMS/NMS communication method between the EMS/NMS and the ingress node is
and the ingress node is beyond the scope of this document (so it is beyond the scope of this document (so it is for any other function
for any other function described in this document). described in this document).
The end-to-end connection is thus created by associating the The end-to-end connection is thus created by associating the incoming
incoming interface of the ingress node with the switched connection interface of the ingress node with the switched connection within the
within the network, and the outgoing interface of the switched network, and the outgoing interface of the switched connection
connection terminating network node (also referred to as egress terminating network node (also referred to as egress node). An SPC
node). An SPC connection is illustrated in the following Figure. connection is illustrated in the following Figure. This shows user's
This shows user's node A connected to a provider's node B via link node A connected to a provider's node B via link #1, user's node Z
#1, user's node Z connected to a provider's node Y via link #3, and connected to a provider's node Y via link #3, and an abstract link #2
an abstract link #2 connecting provider's node B and node Y. Nodes connecting provider's node B and node Y. Nodes B and Y are referred
B and Y are referred to as the ingress and egress (respectively) of to as the ingress and egress (respectively) of the network switched
the network switched connection. connection.
--- --- --- --- --- --- --- ---
| A |--1--| B |-----2-//------| Y |--3--| Z | | A |--1--| B |-----2-//------| Y |--3--| Z |
--- --- --- --- --- --- --- ---
In this instance, the connection on link #1 and link #3 are both In this instance, the connection on link #1 and link #3 are both
provisioned (permanent connections that may be simple links). In provisioned (permanent connections that may be simple links). In
contrast, the connection over link #2 is set up using the contrast, the connection over link #2 is set up using the distributed
distributed control plane. Thus the SPC is composed of the stitching
of link #1, #2 and #3. D.Papadimitriou et al. - Expires April 2005 4
control plane. Thus the SPC is composed of the stitching of link #1,
#2 and #3.
Thus, to support the capability to request an SPC connection: Thus, to support the capability to request an SPC connection:
- The GMPLS signaling protocol must be capable of supporting the - The GMPLS signaling protocol MUST be capable of supporting the
ability to indicate the outgoing link and label information used ability to indicate the outgoing link and label information used
when setting up the destination provisioned connection. when setting up the destination provisioned connection.
- In addition, due to the inter-domain applicability of ASON - In addition, due to the inter-domain applicability of ASON
networks, the GMPLS signaling protocol should also support networks, the GMPLS signaling protocol SHOULD also support
indication of the service level requested for the SPC. In the case indication of the service level requested for the SPC. In the case
where an SPC spans multiple domains, indication of both source and where an SPC spans multiple domains, indication of both source and
destination endpoints controlling the SPC request may be needed. destination endpoints controlling the SPC request MAY be needed.
These MAY be done via the source and destination signaling
D.Papadimitriou et al. - Expires October 2004 4
These may be done via the source and destination signaling
controller addresses. controller addresses.
Note that the association at the ingress node between the permanent Note that the association at the ingress node between the permanent
connection and the switched connection is an implementation matter connection and the switched connection is an implementation matter
that may be under the control of the EMS/NMS and is not within the that may be under the control of the EMS/NMS and is not within the
scope of the signaling protocol. It is, therefore, outside the scope scope of the signaling protocol. It is, therefore, outside the scope
of this document. of this document.
4.2 Support for Call and Connection Separation 4.2 Support for Call and Connection Separation
A call may be simply described as "An association between endpoints A call may be simply described as "An association between endpoints
that supports an instance of a service" [ITU-T G.8080]. Thus, it can that supports an instance of a service" [ITU-T G.8080]. Thus, it can
be considered as a service provided between two end-points, where be considered as a service provided between two end-points, where
several calls may exist between them. Multiple connections may be several calls may exist between them. Multiple connections may be
associated to each call. The call concept provides an abstract associated to each call. The call concept provides an abstract
relationship between two users, where this relationship describes relationship between two users, where this relationship describes (or
(or verifies) to what extent the users are willing to offer (or verifies) to what extent the users are willing to offer (or accept)
accept) service to each other. Therefore, a call does not provide service to each other. Therefore, a call does not provide the actual
the actual connectivity for transmitting user traffic, but only connectivity for transmitting user traffic, but only builds a
builds a relationship by which subsequent connections may be made. relationship by which subsequent connections may be made.
A call may be associated with zero, one or multiple connections. For A call MAY be associated with zero, one or multiple connections. For
the same call, connections may be of different types and each the same call, connections MAY be of different types and each
connection may exist independently of other connections, i.e., each connection MAY exist independently of other connections, i.e., each
connection is setup and released with separate signaling messages. connection is setup and released with separate signaling messages.
The concept of the call allows for a better flexibility in how end- The concept of the call allows for a better flexibility in how end-
points set up connections and how networks offer services to users. points set up connections and how networks offer services to users.
For example, a call allows: For example, a call allows:
- An upgrade strategy for control plane operations, where a call - An upgrade strategy for control plane operations, where a call
control component (service provisioning) may be separate from the control component (service provisioning) may be separate from the
actual nodes hosting the connections (where the connection control actual nodes hosting the connections (where the connection control
component may reside) component may reside)
- Identification of the call initiator (with both network call - Identification of the call initiator (with both network call
controller as well as destination user) prior to connection, which controller as well as destination user) prior to connection, which
may result in decreasing contention during resource reservation may result in decreasing contention during resource reservation
- General treatment of multiple connections which may be associated - General treatment of multiple connections which may be associated
for several purposes; for example a pair of working and recovery for several purposes; for example a pair of working and recovery
connections may belong to the same call. connections may belong to the same call.
D.Papadimitriou et al. - Expires April 2005 5
To support the introduction of the call concept, GMPLS signaling To support the introduction of the call concept, GMPLS signaling
should include a call identification mechanism and allow for end-to- SHOULD include a call identification mechanism and SHOULD allow for
end call capability exchange. end-to-end call capability exchange.
For instance, a feasible structure for the call identifier (to For instance, a feasible structure for the call identifier (to
guarantee global uniqueness) may concatenate a globally unique fixed guarantee global uniqueness) MAY concatenate a globally unique fixed
ID (e.g., may be composed of country code, carrier code) with an ID (e.g., may be composed of country code, carrier code) with an
operator specific ID (where the operator specific ID may be composed operator specific ID (where the operator specific ID may be composed
of a unique access point code - such as source node address - and a of a unique access point code - such as source node address - and a
local identifier). Other formats shall also be possible depending on local identifier). Other formats SHALL also be possible depending on
D.Papadimitriou et al. - Expires October 2004 5
the call identification conventions between parties involved in the the call identification conventions between parties involved in the
call setup process. call setup process.
4.3 Support for Call Segments 4.3 Support for Call Segments
As described in [ITU-T G.8080], call segmentation may be applied As described in [ITU-T G.8080], call segmentation MAY be applied when
when a call crosses several control domains. As such, an end-to-end a call crosses several control domains. As such, an end-to-end call
call may consist of multiple call segments, when the call traverses MAY consist of multiple call segments, when the call traverses
multiple control domains. For a given end-to-end call, each call multiple control domains. For a given end-to-end call, each call
segment can have one or more associated connections and the number segment MAY have one or more associated connections and the number of
of connections associated with each call segment may be different. connections associated with each call segment MAY be different.
The initiating caller interacts with the called party by means of The initiating caller interacts with the called party by means of one
one or more intermediate network call controllers located at control or more intermediate network call controllers located at control
domain boundaries (i.e., at inter-domain reference points, UNI or E- domain boundaries (i.e., at inter-domain reference points, UNI or E-
NNI). Call segment capabilities are defined by the policies NNI). Call segment capabilities are defined by the policies
associated at these reference points. associated at these reference points.
This capability allows for independent (policy based) choices of This capability allows for independent (policy based) choices of
signaling, concatenation, data plane protection and control plane signaling, concatenation, data plane protection and control plane
driven recovery paradigms in different control domains. driven recovery paradigms in different control domains.
4.4 Support for Extended Restart Capabilities 4.4 Support for Extended Restart Capabilities
Various types of failures may occur affecting the ASON control Various types of failures may occur affecting the ASON control plane.
plane. Requirements placed on the control plane failure recovery by Requirements placed on the control plane failure recovery by [ITU-T
[ITU-T G.8080] include: G.8080] include:
- Any control plane failure must not result in releasing established - Any control plane failure (i.e. single or multiple control channel
calls and connections (including the corresponding transport plane and/or controller failure and any combination) MUST NOT result in
connections). releasing established calls and connections (including the
corresponding transport plane connections).
- Upon recovery from a control plane failure, the recovered control - Upon recovery from a control plane failure, the recovered control
entity must have the ability to recover the status of the calls entity MUST have the ability to recover the status of the calls
and connections established before failure occurrence. and connections established before failure occurrence.
- Upon recovery from a control plane failure, the recovered control - Upon recovery from a control plane failure, the recovered control
entity must have the ability to recover the connectivity entity MUST have the ability to recover the connectivity
information of its neighbors. information of its neighbors.
D.Papadimitriou et al. - Expires April 2005 6
- Upon recovery from a control plane failure, the recovered control - Upon recovery from a control plane failure, the recovered control
entity must have the ability to recover the association between entity MUST have the ability to recover the association between
the call and its associated connections must be recovered. the call and its associated connections.
- Upon recovery from a control plane failure, calls and connections - Upon recovery from a control plane failure, calls and connections
in the process of being established (i.e. pending call/connection in the process of being established (i.e. pending call/connection
setup requests) should be released or continued (with setup). setup requests) SHOULD be released or continued (with setup).
- Upon recovery from a control plane failure, calls and connections - Upon recovery from a control plane failure, calls and connections
in the process of being released must be released. in the process of being released MUST be released.
D.Papadimitriou et al. - Expires October 2004 6
4.5 Support for Extended Label Association 4.5 Support for Extended Label Association
It is an ASON requirement to enable support for G.805 serial It is an ASON requirement to enable support for G.805 serial compound
compound links. The text below provides an illustrative example of links. The text below provides an illustrative example of such a
such a scenario, and the associated requirements. scenario, and the associated requirements.
Labels are defined in GMPLS (see [RFC 3471]) to provide information Labels are defined in GMPLS (see [RFC3471]) to provide information on
on the resources used on link local basis for a particular the resources used on link local basis for a particular connection.
connection. The labels may range from specifying a particular The labels may range from specifying a particular timeslot, a
timeslot, a particular wavelength to a particular port/fiber. In the particular wavelength to a particular port/fiber. In the ASON
ASON context, the value of a label MAY not be consistently the same context, the value of a label may not be consistently the same across
across a link. For example, the figure below illustrates the case a link. For example, the figure below illustrates the case where two
where two GMPLS capable nodes (A and Z) are interconnected across GMPLS capable nodes (A and Z) are interconnected across two non-GMPLS
two non-GMPLS capable nodes (B and C), where these nodes are all capable nodes (B and C), where these nodes are all SONET/SDH nodes
SONET/SDH nodes providing, e.g., a VC-4 service. providing, e.g., a VC-4 service.
----- ----- ----- -----
| | --- --- | | | | --- --- | |
| A |---| B |---| C |---| Z | | A |---| B |---| C |---| Z |
| | --- --- | | | | --- --- | |
----- ----- ----- -----
Labels have an associated implicit imposed structure based on Labels have an associated implicit imposed structure based on
[GMPLS-SONET] and [GMPLS-OTN]. Thus, once the local label is [GMPLS-SONET] and [GMPLS-OTN]. Thus, once the local label is
exchanged with its neighboring control plane node, the structure of exchanged with its neighboring control plane node, the structure of
the local label MAY not be significant to the neighbor node since the local label may not be significant to the neighbor node since the
the association between the local and the remote label may not association between the local and the remote label may not
necessarily be the same. This issue does not present a problem in necessarily be the same. This issue does not present a problem in
simple point-to-point connections between two control plane-enabled simple point-to-point connections between two control plane-enabled
nodes where the timeslots are mapped 1:1 across the interface. nodes where the timeslots are mapped 1:1 across the interface.
However, once a non-GMPLS capable sub-network is introduced between However, once a non-GMPLS capable sub-network is introduced between
these nodes (as in the above figure, where the sub-network provides these nodes (as in the above figure, where the sub-network provides
re-arrangement capability for the timeslots) label scoping MAY re-arrangement capability for the timeslots) label scoping may become
become an issue. an issue.
In this context, there is an implicit assumption that the data plane In this context, there is an implicit assumption that the data plane
connections between the GMPLS capable edges already exist prior to connections between the GMPLS capable edges already exist prior to
any connection request. For instance, node A's outgoing VC-4's 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- timeslot #1 (with SUKLM label=[1,0,0,0,0]) as defined in [GMPLS-
SONET]) may be mapped onto node B's outgoing VC-4's timeslot #6 SONET]) may be mapped onto node B's outgoing VC-4's timeslot #6
(label=[6,0,0,0,0]) may be mapped onto node C's outgoing VC-4's (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 this capability, a label association mechanism D.Papadimitriou et al. - Expires April 2005 7
has to be used by the control plane node to map the received timeslot #4 (label=[4,0,0,0,0]). Thus by the time node Z receives the
(remote) label into a locally significant label. The information request from node A with label=[1,0,0,0,0], the node Z's local label
necessary to allow mapping from received label value to a locally and the timeslot no longer corresponds to the received label and
significant label value may be derived in several ways including: timeslot information.
D.Papadimitriou et al. - Expires October 2004 7 As such, to support this capability, a label association mechanism
SHOULD 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 received label value to a locally significant
label value can be derived in several ways including:
- Manual provisioning of the label association - Manual provisioning of the label association
- Discovery of the label association - Discovery of the label association
Either method may be used. In case of dynamic association, this Either method MAY be used. In case of dynamic association, this
implies that the discovery mechanism operates at the timeslot/label implies that the discovery mechanism operates at the timeslot/label
level before the connection request is processed at the ingress level before the connection request is processed at the ingress node.
node. Note that in the case where two nodes are directly connected, Note that in the case where two nodes are directly connected, no
no association is required. In particular, for directly connected association is required. In particular, for directly connected TDM
TDM interfaces no mapping function (at all) is required due to the interfaces no mapping function (at all) is required due to the
implicit label structure (see [GMPLS-SONET] and [GMPLS-OTN]). In implicit label structure (see [GMPLS-SONET] and [GMPLS-OTN]). In such
such instances, the label association function provides a one-to-one instances, the label association function provides a one-to-one
mapping of the received to local label values. mapping of the received to local label values.
4.6 Support for Crankback 4.6 Support for Crankback
Crankback has been identified as an important requirement for ASON Crankback has been identified as an important requirement for ASON
networks. It allows a connection setup request to be retried on an networks. It allows a connection setup request to be retried on an
alternate path that detours around a blocked link or node upon a alternate path that detours around a blocked link or node upon a
setup failure, for instance, because a link or a node along the setup failure, for instance, because a link or a node along the
selected path has insufficient resources. selected path has insufficient resources.
Crankback mechanisms may also be applied during connection recovery Crankback mechanisms MAY also be applied during connection recovery
by indicating the location of the failed link or node. This would by indicating the location of the failed link or node. This would
significantly improve the successful recovery ratio for failed significantly improve the successful recovery ratio for failed
connections, especially in situations where a large number of setup connections, especially in situations where a large number of setup
requests are simultaneously triggered. requests are simultaneously triggered.
The following mechanisms are assumed during crankback signaling: The following mechanisms are assumed during crankback signaling:
- the blocking resource (link or node) must be identified and - the blocking resource (link or node) MUST be identified and
returned in the error response message towards the repair node returned in the error response message towards the repair node
(that may or may not be the ingress node); it is also assumed that (that may or may not be the ingress node); it is also assumed that
this process will occur within a limited period of time this process will occur within a limited period of time
- the computation (from the repair node) of an alternate path around - the computation (from the repair node) of an alternate path around
the blocking link or node that satisfies the initial connection the blocking link or node that satisfies the initial connection
constraints constraints
- the re-initiation of the connection setup request from the repair - the re-initiation of the connection setup request from the repair
node (i.e. the node that has intercepted and processed the error node (i.e. the node that has intercepted and processed the error
response message) response message)
skipping to change at line 408 skipping to change at line 425
(that may or may not be the ingress node); it is also assumed that (that may or may not be the ingress node); it is also assumed that
this process will occur within a limited period of time this process will occur within a limited period of time
- the computation (from the repair node) of an alternate path around - the computation (from the repair node) of an alternate path around
the blocking link or node that satisfies the initial connection the blocking link or node that satisfies the initial connection
constraints constraints
- the re-initiation of the connection setup request from the repair - the re-initiation of the connection setup request from the repair
node (i.e. the node that has intercepted and processed the error node (i.e. the node that has intercepted and processed the error
response message) response message)
The following properties are expected for crankback signaling: The following properties are expected for crankback signaling:
- Error information persistence: the entity that computes the - Error information persistence: the entity that computes the
alternate (re-routing) path should store the identifiers of the alternate (re-routing) path SHOULD store the identifiers of the
D.Papadimitriou et al. - Expires April 2005 8
blocking resources as indicated in the error message until the blocking resources as indicated in the error message until the
connection is successfully established or until the node abandons connection is successfully established or until the node abandons
rerouting attempts. Since crankback may happen more than once rerouting attempts. Since crankback may happen more than once
while establishing a specific connection, the history of all while establishing a specific connection, the history of all
experienced blockages for this connection should be maintained (at experienced blockages for this connection SHOULD be maintained (at
least until the routing protocol updates the state of this least until the routing protocol updates the state of this
information) to perform an accurate path computation avoiding all information) to perform an accurate path computation avoiding all
blockages. blockages.
D.Papadimitriou et al. - Expires October 2004 8
- Rerouting attempts limitation: to prevent an endless repetition of - Rerouting attempts limitation: to prevent an endless repetition of
connection setup attempts (using crankback information), the connection setup attempts (using crankback information), the
number of retries should be strictly limited. The maximum number number of retries SHOULD be strictly limited. The maximum number of
of crankback rerouting attempts allowed can be limited per crankback rerouting attempts allowed MAY be limited per connection
connection, per node, per area or even per administrative domain. or per node:
- When the number of retries at a particular node or area is - When the number of retries at a particular node is exceeded, the
exceeded, the node currently handling the failure reports the node currently handling the failure reports the error message
error message upstream to the next repair node where further upstream to the next repair node where further rerouting attempts
rerouting attempts may be performed. It is important that the MAY be performed. It is important that the crankback information
crankback information provided indicates that re-routing provided indicates that re-routing through this node will not
through this node will not succeed. succeed.
- When the maximum number of retries for a specific connection - When the maximum number of retries for a specific connection
has been exceeded, the repair node handling the current has been exceeded, the repair node handling the current
failure should send an error message upstream indicating failure SHOULD send an error message upstream indicating
"Maximum number of re-routings exceeded". This error message "Maximum number of re-routings exceeded". This error message
will be sent back to the ingress node with no further will be sent back to the ingress node with no further
rerouting attempts. Then, the ingress node may choose to rerouting attempts. Then, the ingress node MAY choose to
retry the connection setup according to local policy but also retry the connection setup according to local policy but also
re-use its original path or compute a path that avoids the re-use its original path or compute a path that avoids the
blocking resources. blocking resources.
Note: after several retries, a given repair point may be unable to Note: after several retries, a given repair point MAY be unable to
compute a path to the destination node that avoids all of the compute a path to the destination node that avoids all of the
blockages. In this case, it must pass the error message upstream to blockages. In this case, it MUST pass the error message upstream to
the next repair point. the next repair point.
4.7 Support for Additional Error Cases 4.7 Support for Additional Error Cases
To support the ASON network, the following additional category of To support the ASON network, the following additional category of
error cases are defined: error cases are defined:
- Errors associated with basic call and soft permanent connection - Errors associated with basic call and soft permanent connection
support. For example, these may include incorrect assignment of support. For example, these MAY include incorrect assignment of
IDs for the Call or an invalid interface ID for the soft permanent IDs for the Call or an invalid interface ID for the soft permanent
connection. connection.
- Errors associated with policy failure during processing of the new - Errors associated with policy failure during processing of the new
call and soft permanent connection capabilities. These may include call and soft permanent connection capabilities. These MAY include
unauthorized request for the particular capability. unauthorized request for the particular capability.
- Errors associated with incorrect specification of the service - Errors associated with incorrect specification of the service
level. level.
5. Backward Compatibility 5. Backward Compatibility
D.Papadimitriou et al. - Expires April 2005 9
As noted above, in support of GMPLS protocol requirements, any As noted above, in support of GMPLS protocol requirements, any
extensions to the GMPLS signaling protocol in support of the extensions to the GMPLS signaling protocol in support of the
requirements described in this document must be backward compatible. requirements described in this document MUST be backward compatible.
Backward compatibility means that in a network of nodes, some of Backward compatibility means that in a network of nodes, some of
which support GMPLS signaling extensions to facilitate the functions which support GMPLS signaling extensions to facilitate the functions
described in this document, and some of which do not, it must be described in this document, and some of which do not, it MUST be
possible to set up conventional connections (as described by [RFC possible to set up conventional connections (as described by [RFC
3473]) between any arbitrary pair of nodes and traversing any 3473]) between any arbitrary pair of nodes and traversing any
arbitrary set of nodes. Further, the use of any GMPLS signaling arbitrary set of nodes. Further, the use of any GMPLS signaling
D.Papadimitriou et al. - Expires October 2004 9
extensions to set up calls or connections that support the functions extensions to set up calls or connections that support the functions
described in this document must not perturb existing conventional described in this document MUST not perturb existing conventional
connections. connections.
Additionally, when transit nodes, that do not need to participate in Additionally, when transit nodes, that do not need to participate in
the new functions described in this document, lie on the path of a the new functions described in this document, lie on the path of a
call or connection, the GMPLS signaling extensions must be such that call or connection, the GMPLS signaling extensions MUST be such that
those transit nodes are able to participate in the establishment of those transit nodes are able to participate in the establishment of
the call or connection by passing the setup information onwards, the call or connection by passing the setup information onwards,
unmodified. unmodified.
Lastly, when a transit or egress node is called upon to support a Lastly, when a transit or egress node is called upon to support a
function described in this document, but does not, the GMPLS function described in this document, but does not, the GMPLS
signaling extensions must be such that they can be rejected by pre- signaling extensions MUST be such that they can be rejected by pre-
existing GMPLS signaling mechanisms in a way that is not detrimental existing GMPLS signaling mechanisms in a way that is not detrimental
to the network as a whole. to the network as a whole.
6. Security Considerations 6. Security Considerations
Per [ITU-T G.8080], it is not possible to establish a connection in Per [ITU-T G.8080], it is not possible to establish a connection in
advance of call setup completion. Also, policy and authentication advance of call setup completion. Also, policy and authentication
procedures are applied prior to the establishment of the call (and procedures are applied prior to the establishment of the call (and
can then also be restricted to connection establishment in the can then also be restricted to connection establishment in the
context of this call). context of this call).
This document introduces no new security requirements to GMPLS This document introduces no new security requirements to GMPLS
signaling (see [RFC 3471]). signaling (see [RFC 3471]).
7. Intellectual Property Consideration 7. Acknowledgements
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights 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; nor does it represent that
it has made any independent effort to identify any such rights.
Information on the procedures with respect to rights in RFC
documents can be found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat 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 implementers or users of this
specification can be obtained from the IETF on-line IPR repository
at http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at ietf-
ipr@ietf.org.
D.Papadimitriou et al. - Expires October 2004 10
7.1 IPR Disclosure Acknowledgement
By submitting this Internet-Draft, I certify that any applicable
patent or other IPR claims of which I am aware have been disclosed,
and any of which I become aware will be disclosed, in accordance
with RFC 3668.
8. Acknowledgements
The authors would like to thank Nic Larkin, Osama Aboul-Magd and The authors would like to thank Nic Larkin, Osama Aboul-Magd and
Dimitrios Pendarakis for their contribution to the previous version Dimitrios Pendarakis for their contribution to the previous version
of this document, Zhi-Wei Lin for his contribution to this document, of this document, Zhi-Wei Lin for his contribution to this document,
Deborah Brungard for her input and guidance in our understanding of Deborah Brungard for her input and guidance in our understanding of
the ASON model, and Gert Grammel for his decryption effort during the ASON model, and Gert Grammel for his decryption effort during the
the reduction of some parts of this document. reduction of some parts of this document.
9. References 8. References
9.1 Normative References 8.1 Normative References
[RFC 2026] S.Bradner, "The Internet Standards Process -- [RFC 2026] S.Bradner, "The Internet Standards Process --
D.Papadimitriou et al. - Expires April 2005 10
Revision 3", BCP 9, RFC 2026, October 1996. Revision 3", BCP 9, RFC 2026, October 1996.
[RFC 2119] S.Bradner, "Key words for use in RFCs to Indicate [RFC 2119] S.Bradner, "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC 3209] D.Awduche et al., "RSVP-TE: Extensions to RSVP for [RFC 3209] D.Awduche et al., "RSVP-TE: Extensions to RSVP for
LSP Tunnels," RFC 3209, December 2001. LSP Tunnels," RFC 3209, December 2001.
[RFC 3471] L.Berger (Editor) et al., "Generalized Multi- [RFC 3471] L.Berger (Editor) et al., "Generalized Multi-
Protocol Label Switching (GMPLS) - Signaling Protocol Label Switching (GMPLS) - Signaling
Functional Description," RFC 3471, January 2003. Functional Description," RFC 3471, January 2003.
[RFC 3473] L.Berger (Editor) et al., "Generalized Multi-Protocol [RFC 3473] L.Berger (Editor) et al., "Generalized Multi-Protocol
Label Switching (GMPLS) Signaling - Resource Label Switching (GMPLS) Signaling - Resource
ReserVation Protocol-Traffic Engineering (RSVP-TE) ReserVation Protocol-Traffic Engineering (RSVP-TE)
Extensions," RFC 3473, January 2003. Extensions," RFC 3473, January 2003.
[ITU-T G.8080] ITU-T "Architecture for the Automatically Switched [RFC3667] S.Bradner, "IETF Rights in Contributions", BCP 78,
Optical Network (ASON)," Recommendation G.8080/ RFC 3667, February 2004.
Y.1304, November 2001 (and Revision, January 2003).
9.2 Informative References [RFC3668] S.Bradner, Ed., "Intellectual Property Rights in IETF
Technology", BCP 79, RFC 3668, February 2004.
8.2 Informative References
[GMPLS-OTN] D.Papadimitriou (Editor), "GMPLS Signaling Extensions [GMPLS-OTN] D.Papadimitriou (Editor), "GMPLS Signaling Extensions
for G.709 Optical Transport Networks Control," Work for G.709 Optical Transport Networks Control," Work
in progress, draft-ietf-ccamp-gmpls-g709-07.txt, in progress, draft-ietf-ccamp-gmpls-g709-08.txt,
March 2004. September 2004.
[GMPLS-OVERLAY]G.Swallow et al., "GMPLS RSVP Support for Overlay [GMPLS-OVERLAY]G.Swallow et al., "GMPLS RSVP Support for Overlay
Model," Work in Progress, draft-ietf-ccamp-gmpls- Model," Work in Progress, draft-ietf-ccamp-gmpls-
overlay-03.txt, February 2004. overlay-05.txt, October 2004.
D.Papadimitriou et al. - Expires October 2004 11
[GMPLS-SONET] E.Mannie and D.Papadimitriou (Editors), "GMPLS [GMPLS-SONET] E.Mannie and D.Papadimitriou (Editors), "GMPLS
Extensions for SONET and SDH Control, Work in Extensions for SONET and SDH Control, Work in
Progress," draft-ietf-ccamp-gmpls-sonet-sdh-08.txt, Progress," draft-ietf-ccamp-gmpls-sonet-sdh-08.txt,
February 2003. February 2003.
[GMPLS-VPN] H.Ould-Brahim and Y.Rekhter (Editor), "GVPN Services: [GMPLS-VPN] H.Ould-Brahim and Y.Rekhter (Editors), "GVPN Services:
Generalized VPN Services using BGP and GMPLS Generalized VPN Services using BGP and GMPLS
Toolkit," Work in Progress, draft-ouldbrahim-ppvpn- Toolkit," Work in Progress, draft-ouldbrahim-ppvpn-
gvpn-bgpgmpls-04.txt, October 2003. gvpn-bgpgmpls-05.txt, May 2004.
For information on the availability of the following documents,
please see http://www.itu.int.
[ITU-T G.7713] ITU-T "Distributed Call and Connection Management," [ITU-T G.7713] ITU-T "Distributed Call and Connection Management,"
Recommentation G.7713/Y.1304, November 2001. Recommentation G.7713/Y.1304, November 2001.
10. Author's Addresses [ITU-T G.8080] ITU-T "Architecture for the Automatically Switched
Optical Network (ASON)," Recommendation G.8080/
D.Papadimitriou et al. - Expires April 2005 11
Y.1304, November 2001 (and Revision, January 2003).
9. Author's Addresses
Dimitri Papadimitriou (Alcatel) Dimitri Papadimitriou (Alcatel)
Francis Wellesplein 1, Francis Wellesplein 1,
B-2018 Antwerpen, Belgium B-2018 Antwerpen, Belgium
Phone: +32 3 2408491 Phone: +32 3 2408491
EMail: dimitri.papadimitriou@alcatel.be EMail: dimitri.papadimitriou@alcatel.be
John Drake (Calient) John Drake (Calient)
5853 Rue Ferrari, 5853 Rue Ferrari,
San Jose, CA 95138, USA San Jose, CA 95138, USA
skipping to change at line 625 skipping to change at line 619
AT&T Labs, Room MT D5-2A01 AT&T Labs, Room MT D5-2A01
200 Laurel Avenue 200 Laurel Avenue
Middletown, NJ 07748, USA Middletown, NJ 07748, USA
EMail: gash@att.com EMail: gash@att.com
Lyndon Ong (Ciena) Lyndon Ong (Ciena)
5965 Silver Creek Valley Road 5965 Silver Creek Valley Road
San Jose, CA 95138, USA San Jose, CA 95138, USA
EMail: lyong@ciena.com EMail: lyong@ciena.com
D.Papadimitriou et al. - Expires October 2004 12 D.Papadimitriou et al. - Expires April 2005 12
Appendix - Terminology Appendix - Terminology
This document makes use of the following terms: This document makes use of the following terms:
Administrative domain: See Recommendation G.805. Administrative domain: See Recommendation G.805.
Call: association between endpoints that supports an instance of a Call: association between endpoints that supports an instance of a
service. service.
Connection: concatenation of link connections and sub-network Connection: concatenation of link connections and sub-network
connections that allows the transport of user information between connections that allows the transport of user information between the
the ingress and egress points of a sub-network. ingress and egress points of a sub-network.
Control plane: performs the call control and connection control Control plane: performs the call control and connection control
functions. Through signaling, the control plane sets up and releases functions. Through signaling, the control plane sets up and releases
connections, and may restore a connection in case of a failure. connections, and may restore a connection in case of a failure.
(Control) Domain: represents a collection of entities that are (Control) Domain: represents a collection of entities that are
grouped for a particular purpose. G.8080 applies this G.805 grouped for a particular purpose. G.8080 applies this G.805
recommendation concept (that defines two particular forms, the recommendation concept (that defines two particular forms, the
administrative domain and the management domain) to the control administrative domain and the management domain) to the control plane
plane in the form of a control domain. The entities that are grouped in the form of a control domain. The entities that are grouped in a
in a control domain are components of the control plane. control domain are components of the control plane.
External NNI (E-NNI): interfaces are located between protocol External NNI (E-NNI): interfaces are located between protocol
controllers between control domains. controllers between control domains.
Internal NNI (I-NNI): interfaces are located between protocol Internal NNI (I-NNI): interfaces are located between protocol
controllers within control domains. controllers within control domains.
Link: See Recommendation G.805. Link: See Recommendation G.805.
Management plane: performs management functions for the Transport Management plane: performs management functions for the Transport
skipping to change at line 673 skipping to change at line 667
fault, configuration, accounting and security management fault, configuration, accounting and security management
Management domain: See Recommendation G.805. Management domain: See Recommendation G.805.
Transport plane: provides bi-directional or unidirectional transfer Transport plane: provides bi-directional or unidirectional transfer
of user information, from one location to another. It can also of user information, from one location to another. It can also
provide transfer of some control and network management information. provide transfer of some control and network management information.
The Transport Plane is layered; it is equivalent to the Transport The Transport Plane is layered; it is equivalent to the Transport
Network defined in G.805. Network defined in G.805.
User Network Interface (UNI): interfaces are located between User Network Interface (UNI): interfaces are located between protocol
protocol controllers between a user and a control domain. controllers between a user and a control domain.
D.Papadimitriou et al. - Expires October 2004 13 D.Papadimitriou et al. - Expires April 2005 13
Full Copyright Statement Intellectual Property Statement
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights 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; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat 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 implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at
ietf-ipr@ietf.org.
Disclaimer of Validity
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM 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.
Copyright Statement
Copyright (C) The Internet Society (2004). This document is subject Copyright (C) The Internet Society (2004). This document is subject
to the rights, licenses and restrictions contained in BCP 78 and to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights. except as set forth therein, the authors retain all their rights.
This document and the information contained herein are provided on Acknowledgment
an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE
REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE
INTERNET ENGINEERING TASK FORCE DISCLAIM 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.
D.Papadimitriou et al. - Expires October 2004 14 Funding for the RFC Editor function is currently provided by the
Internet Society.
D.Papadimitriou et al. - Expires April 2005 14
 End of changes. 

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