draft-ietf-ccamp-gmpls-ason-reqts-05.txt   draft-ietf-ccamp-gmpls-ason-reqts-06.txt 
CCAMP Working Group D. Papadimitriou (Alcatel) CCAMP 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) A. Farrel (Old Dog Consulting)
Expiration Date: May 2004 L. Ong (Ciena) Expiration Date: October 2004 L. Ong (Ciena)
November 2003 April 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-05.txt draft-ietf-ccamp-gmpls-ason-reqts-06.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 in full conformance with
all provisions of Section 10 of RFC-2026. all provisions of Section 10 of RFC-2026.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Internet-Drafts are draft documents valid for a maximum of Drafts. Internet-Drafts are draft documents valid for a maximum of
skipping to change at line 49 skipping to change at line 48
applications. These include support for requesting TDM connections applications. These include support for requesting TDM connections
including SONET/SDH and Optical Transport Networks (OTNs). including SONET/SDH and Optical Transport Networks (OTNs).
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 a problem statement and additional requirements on the provides a problem statement and additional requirements on the
GMPLS signaling protocol to support the ASON functionality. GMPLS signaling protocol to support the ASON functionality.
D.Papadimitriou et al. - Expires May 2004 1 D.Papadimitriou et al. - Expires October 2004 1
2. Conventions used in this document 2. 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 document are to be interpreted as described in RFC-2119. this document are to be interpreted as described in [RFC 2119].
3. Introduction 3. Introduction
The GMPLS suite of protocol specifications provides support for The GMPLS suite of protocol specifications provides support for
controlling different switching technologies as well as different controlling different switching technologies as well as different
applications. These include support for requesting TDM connections applications. These include support for requesting TDM connections
including SONET/SDH (see ANSI T1.105 and ITU-T G.707, respectively) including SONET/SDH (see ANSI T1.105 and ITU-T G.707, respectively)
as well as Optical Transport Networks (see ITU-T G.709). In as well as Optical Transport Networks (see ITU-T G.709). In
addition, there are certain capabilities that are needed to support addition, there are certain capabilities that are needed to support
Automatically Switched Optical Networks control planes (their Automatically Switched Optical Networks control planes (their
architecture is defined in [ITU-T G.8080]). These include generic architecture is defined in [ITU-T G.8080]). These include generic
capabilities such as call and connection separation, and more 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 the signaling aspects of the GMPLS This document concentrates on requirements related to the signaling
suite of protocols. It discusses the functional requirements that aspects of the GMPLS suite of protocols. It discusses functional
lead to additional and backward compatible extensions to GMPLS requirements required to support Automatically Switched Optical
signaling (see [RFC 3471] and [RFC 3473]) to support the Networks that MAY lead to additional extensions to GMPLS signaling
capabilities as specified in the above referenced document. A (see [RFC 3471] and [RFC 3473]) to support these capabilities. In
description of backward compatibility considerations is provided in addition to ASON signaling requirements, this document includes
Section 5. A terminology section is provided in the Appendix. GMPLS signaling requirements regarding backward compatibility
(Section 5). A terminology section is provided in the Appendix.
Problem Statement: 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]). detailed description see [ITU-T G.8080]). The ASON architecture
describes a reference architecture, i.e. it describes functional
components, abstract interfaces, and interactions.
Also, the ASON model distinguishes reference points (representing The ASON model distinguishes reference points (representing points
points of protocol information exchange) defined (1) between an of information exchange) defined (1) between a user (service
administrative domain and a user a.k.a. user-network interface requester) and a service provider control domain a.k.a. user-network
(UNI), (2) between (and when needed within) administrative domains interface (UNI), (2) between control domains a.k.a. external
a.k.a. external network-network interface (E-NNI) and, (3) between network-network interface (E-NNI) and, (3) within a control domain
areas of the same administrative domain and when needed between a.k.a. internal network-network interface (I-NNI). The I-NNI and E-
control components (or simply controllers) within areas a.k.a. NNI interfaces are between protocol controllers, and may or may not
internal network-network interface (I-NNI). use transport plane (physical) links. It MUST NOT be assumed that
there is a one-to-one relationship of control plane interfaces and
transport plane (physical) links, or that there is a one-to-one
relationship of control plane entities and transport plane entities,
or that there is a one-to-one relationship of control plane
identifiers for transport plane resources.
This document describes the use of GMPLS signaling (in particular, D.Papadimitriou et al. - Expires October 2004 2
[RFC 3471] and [RFC 3473]) to provide call and connection management This document describes requirements related to the use of GMPLS
(see [ITU-T G.7713]). The following functionality is expected to be signaling (in particular, [RFC 3471] and [RFC 3473]) to provide call
supported and to be backward compatible with the GMPLS protocol and connection management (see [ITU-T G.7713]). The functionality to
suite as currently defined by the IETF: 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
D.Papadimitriou et al. - Expires May 2004 2
(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 following ASON functions: GMPLS to support the ASON functions listed in Section 3. ASON
defines a reference model and functions (information elements) to
- Support for soft permanent connection capability enable end-to-end call and connection support by a protocol across
- Support for call and connection separation the respective interfaces, regardless of the particular choice of
- Support for call segments protocol(s) used in a network. ASON does not restrict the use of
- Support for extended restart capabilities during control plane other protocols or the protocol-specific messages used to support
failures the ASON functions. Therefore, the support of these ASON functions
- Support for extended label association by a protocol shall not be restricted by (i.e. must be strictly
- Support for crankback capability independent of and agnostic to) any particular choice of UNI, I-NNI,
- Support for additional error cases or E-NNI used elsewhere in the network. In order to allow for
interworking between different protocol implementations, [G.7713]
The support of these functions must be strictly independent of and recognizes an interworking function may be needed.
agnostic to any user-to-network interface (UNI) and therefore not be
constrained or restricted by the implementation specifics of the UNI
(see [ITU-T G.8080] and [ITU-T G.7713]).
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
signaling 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 and protocols within the
network. This implies that there needs to be a clear mapping of network. This implies that there needs to be a clear mapping of ASON
signaling requests between GMPLS control domains and non-GMPLS signaling requests between GMPLS control domains and non-GMPLS
control domains. This document provides signalling requirements for control domains. This document provides signalling 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 and between GMPLS based control within a GMPLS based control domain (I-NNI) and between GMPLS based
domains. It does not restrict use of other protocols within a control domains (E-NNI). It does not restrict use of other (non-
control domain. Interworking aspects, including mapping of non-GMPLS GMPLS) protocols to be used within a control domain or as an E-NNI
protocol signaling requests and support of non-GMPLS address or UNI. Interworking aspects related to the use of non-GMPLS
formats, are strictly under the responsibility of the non-GMPLS protocols as UNI, E-NNI, or I-NNI, including mapping of non-GMPLS
control domain, and thus outside the scope of this document. protocol signaling requests to corresponding ASON signaling
functionality and support of non-GMPLS address formats, is not
within the scope of the GMPLS signaling protocol. Interworking
aspects are implementation-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 be a GMPLS UNI and must be supported. to be included within the GMPLS suite of protocols and must be
supported 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 any signaling protocols is described. For instance, Section support any signaling protocols is described. For instance, Section
4.5 'Support for Extended Label Association' covers the requirements 4.5 'Support for Extended Label Association' covers the requirements
when a non-GMPLS capable sub-network is introduced or when nodes do when a non-GMPLS capable sub-network is introduced or when nodes do
not support any signaling protocols. not support any signaling protocols.
D.Papadimitriou et al. - Expires May 2004 3
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-to-network side, a permanent connection at the destination user-to-network side, a permanent connection at the destination
user-to-network side, and a switched connection within the network. user-to-network side, and a switched connection within the network.
An Element Management System (EMS) or a Network Management System An Element Management System (EMS) or a Network Management System
(NMS) typically initiates the establishment of the switched (NMS) typically initiates the establishment of the switched
connection by communicating with the node that initiates the connection by communicating with the node that initiates the
switched connection (also known as the ingress node). The latter switched connection (also known as the ingress node). The latter
then sets the connection using the distributed GMPLS signaling then sets the connection using the distributed GMPLS signaling
skipping to change at line 188 skipping to change at line 195
B and Y are referred to as the ingress and egress (respectively) of B and Y are referred to as the ingress and egress (respectively) of
the network switched connection. the network switched 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 control plane. Thus the SPC is composed of the splicing distributed control plane. Thus the SPC is composed of the stitching
of link #1, #2 and #3. 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.
D.Papadimitriou et al. - Expires October 2004 4
These may be done via the source and destination signaling 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
under the control of the EMS/NMS and is not within the scope of the that may be under the control of the EMS/NMS and is not within the
signaling protocol. It is, therefore, outside the scope of this scope of the signaling protocol. It is, therefore, outside the scope
document. of this document.
D.Papadimitriou et al. - Expires May 2004 4
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 verifies) to what extent the users are willing to offer (or (or verifies) to what extent the users are willing to offer (or
accept) service to each other. Therefore, a call does not provide accept) service to each other. Therefore, a call does not provide
the actual connectivity for transmitting user traffic, but only the actual connectivity for transmitting user traffic, but only
builds a relationship by which subsequent connections may be made. builds a relationship by which subsequent connections may be made.
A property of a call is to contain zero, one or multiple A call may be associated with zero, one or multiple connections. For
connections. Within the same call, connections may be of different the same call, connections may be of different types and each
types and each connection may exist independently of other connection may exist independently of other connections, i.e., each
connections, i.e., each connection is setup and released with connection is setup and released with separate signaling messages.
separate signaling messages. For example, a call may contain a set
of basic connections and virtually concatenated connections (see
[GMPLS-SONET] for corresponding connection signaling extensions).
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.
In essence, a call allows: For example, a call allows:
- Support for virtual concatenation where each connection can travel
on different diverse paths
- 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.
skipping to change at line 258 skipping to change at line 260
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 allow for end-to-
end call capability exchange. 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.
D.Papadimitriou et al. - Expires May 2004 5
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 a call crosses several administrative domains. As such, an end- when a call crosses several control domains. As such, an end-to-end
to-end call may consist of multiple call segments, when the call call may consist of multiple call segments, when the call traverses
traverses multiple administrative domains. For a given end-to-end multiple control domains. For a given end-to-end call, each call
call, each call segment can have one or more associated connections segment can have one or more associated connections and the number
and the number of connections associated with each call segment may of connections associated with each call segment may be different.
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 or more intermediate network call controllers located at one or more intermediate network call controllers located at control
administrative domain boundaries (i.e., inter-domain reference domain boundaries (i.e., at inter-domain reference points, UNI or E-
points). 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 administrative 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. Requirements placed on the control plane failure recovery by plane. Requirements placed on the control plane failure recovery by
[ITU-T G.8080] include: [ITU-T G.8080] include:
- Any control plane failure must not result in releasing established - Any control plane failure must not result in releasing established
calls and connections. calls and connections (including the corresponding transport plane
- Upon recovery from a control plane failure, the recovered node connections).
must have the ability to recover the status of the calls 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 node entity must have the ability to recover the status of the calls
must have the ability to recover the connectivity information of and connections established before failure occurrence.
its neighbors.
- Upon recovery from a control plane failure, the recovered control
entity must have the ability to recover the connectivity
information of its neighbors.
- Upon recovery from a control plane failure, the recovered control
entity must have the ability to recover the association between
the call and its associated connections must be recovered.
- 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.
- Upon recovery from a control plane failure, a call must have
the ability to re-synchronize with its associated connections. 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
compound links. The text below provides an illustrative example of
such a scenario, and the associated requirements.
Labels are defined in GMPLS (see [RFC 3471]) to provide information Labels are defined in GMPLS (see [RFC 3471]) to provide information
on the resources used on link local basis for a particular on the resources used on link local basis for a particular
connection. The labels may range from specifying a particular connection. The labels may range from specifying a particular
timeslot, a particular wavelength to a particular port/fiber. timeslot, a particular wavelength to a particular port/fiber. In the
ASON context, the value of a label MAY not be consistently the same
In the ASON context, the value of a label MAY not be consistently across a link. For example, the figure below illustrates the case
the same across a link. For example, the figure below illustrates where two GMPLS capable nodes (A and Z) are interconnected across
the case where two GMPLS capable nodes (A and Z) are interconnected two non-GMPLS capable nodes (B and C), where these nodes are all
SONET/SDH nodes providing, e.g., a VC-4 service.
D.Papadimitriou et al. - Expires May 2004 6
across two non-GMPLS capable nodes (B and C), where these nodes are
all SONET/SDH nodes 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
skipping to change at line 355 skipping to change at line 367
the request from node A with label=[1,0,0,0,0], the node Z's local 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 label and the timeslot no longer corresponds to the received label
and timeslot information. and timeslot information.
As such, to support this capability, a label association mechanism As such, to support this capability, a label association mechanism
has to be used by the control plane node to map the received has to be used by the control plane node to map the received
(remote) label into a locally significant label. The information (remote) label into a locally significant label. The information
necessary to allow mapping from received label value to a locally necessary to allow mapping from received label value to a locally
significant label value may be derived in several ways including: significant label value may be derived in several ways including:
D.Papadimitriou et al. - Expires October 2004 7
- 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. Note that in the case where two nodes are directly connected, node. Note that in the case where two nodes are directly connected,
no association is required. In particular, for directly connected no association is required. In particular, for directly connected
TDM interfaces no mapping function (at all) is required due to the TDM 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 instances, the label association function provides a one-to-one such 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.
D.Papadimitriou et al. - Expires May 2004 7
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 satisfying 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
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 crankback rerouting attempts allowed can be limited per of crankback rerouting attempts allowed can be limited per
connection, per node, per area or even per administrative domain. connection, per node, per area or even per administrative domain.
- When the number of retries at a particular node or area is - When the number of retries at a particular node or area is
exceeded, the node currently handling the failure reports the exceeded, the node currently handling the failure reports the
error message upstream to the next repair node where further error message upstream to the next repair node where further
rerouting attempts may be performed. It is important that the rerouting attempts may be performed. It is important that the
crankback information provided indicates that re-routing crankback information provided indicates that re-routing
through this node will not succeed. through this node will not 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
D.Papadimitriou et al. - Expires May 2004 8
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
skipping to change at line 453 skipping to change at line 463
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
As noted above, any extensions to the GMPLS signaling protocol in As noted above, in support of GMPLS protocol requirements, any
support of the requirements described in this document must be extensions to the GMPLS signaling protocol in support of the
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
D.Papadimitriou et al. - Expires May 2004 9
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 Per [ITU-T G.8080], it is not possible to establish a connection in
until the associated call has been set up. Also, policy and advance of call setup completion. Also, policy and authentication
authentication procedures are applied prior to the establishment of procedures are applied prior to the establishment of the call (and
the call (and can then also be restricted to connection can then also be restricted to connection establishment in the
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. Acknowledgements 7. Intellectual Property Consideration
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 redaction of some parts of this document. the reduction of some parts of this document.
8. References 9. References
8.1 Normative References 9.1 Normative References
[RFC 2026] S.Bradner, "The Internet Standards Process -- [RFC 2026] S.Bradner, "The Internet Standards Process --
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 Rec. G.8080/Y.1304, "Architecture for the [ITU-T G.8080] ITU-T "Architecture for the Automatically Switched
Automatically Switched Optical Network (ASON)," Optical Network (ASON)," Recommendation G.8080/
November 2001 (and Revision, January 2003). Y.1304, November 2001 (and Revision, January 2003).
D.Papadimitriou et al. - Expires May 2004 10
8.2 Informative References 9.2 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-g709-04.txt, May in progress, draft-ietf-ccamp-gmpls-g709-07.txt,
2003. March 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-02.txt, October 2003. overlay-03.txt, February 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 (Editor), "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-04.txt, October 2003.
[ITU-T G.7713] ITU-T Rec. G.7713/Y.1304, "Distributed Call and [ITU-T G.7713] ITU-T "Distributed Call and Connection Management,"
Connection Management," November 2001. Recommentation G.7713/Y.1304, November 2001.
9. Author's Addresses 10. 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 583 skipping to change at line 625
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
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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.
skipping to change at line 634 skipping to change at line 676
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 controllers between a user and a control domain. protocol controllers between a user and a control domain.
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Full Copyright Statement Full Copyright Statement
"Copyright (C) The Internet Society (2003). All Rights Reserved. Copyright (C) The Internet Society (2004). This document is subject
to the rights, licenses and restrictions contained in BCP 78 and
This document and translations of it may be copied and furnished to except as set forth therein, the authors retain all their rights.
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 This document and the information contained herein are provided on
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
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 End of changes. 

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