CCAMP Working Group Wesam Alanqar (Sprint)
Internet Draft Deborah Brungard (ATT)
Category: Informational Dave Meyer (1-4-5 Net)
Lyndon Ong (Ciena)
Expiration Date: April 2004 Dimitri Papadimitriou (Alcatel)
Jonathan Sadler (Tellabs)
Stephen Shew (Nortel)
October 2003
Requirements for Generalized MPLS (GMPLS) Routing
for Automatically Switched Optical Network (ASON)
draft-alanqar-ccamp-gmpls-ason-routing-reqts-00.txt
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Abstract
The Generalized MPLS (GMPLS) suite of protocols has been defined to
control different switching technologies as well as different
applications. These include support for requesting TDM connections
including SONET/SDH and Optical Transport Networks (OTNs).
This document concentrates on the routing requirements on the GMPLS
suite of protocols to support the capabilities and functionalities
of an Automatically Switched Optical Network (ASON).
*** This draft is in an early stage and propose only a template to
be further developed ***
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1. Contributors
This document is the early stage result of the CCAMP Working Group
ASON Routing Requirements design team joint effort.
2. Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in
this document are to be interpreted as described in RFC-2119.
The reader is also assumed to be familiar with the terminology used
in [G.8080] and [G.7715].
3. Introduction
The GMPLS suite of protocol provides support for controlling
different switching technologies as well as different applications.
These include support for requesting TDM connections including
SONET/SDH (see ANSI T1.105 and ITU-T G.707, respectively) as well as
Optical Transport Networks (see ITU-T G.709). However, there are
certain capabilities that are needed to support Automatically
Switched Optical Networks (ASON) control planes. Therefore, it is
desirable to understand the corresponding requirements for the GMPLS
protocol suite. ASON control plane architecture is defined in
[G.8080] and ASON routing requirements are identified in [G.7715].
Also, the SG15/Q.14 is working on refining these requirements.
This document focuses on the routing requirements for the GMPLS
suite of protocols to support the capabilities and functionalities
of ASON control planes. It discusses the requirements for GMPLS
routing that MAY subsequently lead to additional backward compatible
extensions to support the capabilities specified in the above
referenced document. A description of backward compatibility
considerations is provided in Section 5. Nonetheless, any protocol
(in particular, routing) design or suggested protocol extensions is
strictly outside the scope of this document. A terminology section
(that may be further completed) is provided in the Appendix.
The ASON model distinguishes reference points (representing points
of protocol information exchange) defined (1) between an
administrative domain and a user a.k.a. user-network interface
(UNI), (2) between (and when needed within) administrative domains
a.k.a. external network-network interface (E-NNI) and, (3) between
areas of the same administrative domain and when needed between
control components (or simply controllers) within areas a.k.a.
internal network-network interface (I-NNI).
The ASON routing architectural model is based on the following
assumptions:
- The information exchanged between routing controllers is subject
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to policy constraints imposed at reference points (E-NNI and I-
NNI)
- The routing information exchanged between routing domains (i.e.
inter-domain) is independent of intra-domain routing protocol
- The routing information exchanged between routing domains is
independent of intra-domain control distribution choices, e.g.
centralized, fully distributed
- The routing adjacency topology and transport network topology
shall not be assumed to be congruent
- Each routing area shall be uniquely identifiable within a
carrier's network (constituted by several routing domains)
The following functionality is to be supported by GMPLS routing to
instantiate ASON routing realization:
- support multiple hierarchical levels
- support hierarchical routing information dissemination including
summarized routing information
- support for multiple links between nodes (and allow for link and
node diversity)
- support architectural evolution in terms of the number of levels
of hierarchies, aggregation and segmentation of (control ?)
domains
- support routing information divided between attributes pertaining
to links and nodes (representing either a routing area or
sub-network)
In addition the behaviour of GMPLS routing is expected to be such
that:
- it is scalable with respect to the number of links, nodes and
routing area hierarchical levels. - what does this means ? is it
routing areas and hierarchical levels ? or hierarchical levels of
routing areas -
- in response to a routing event (e.g. topology update, reachability
update), it delivers convergence and damping against flapping
- it fulfils the operational security objectives where required
4. ASON Requirements for GMPLS Routing
The next sections detail the requirements for GMPLS routing to
support the following ASON routing functions:
- supporting multiple hierarchical levels
- support hierarchical routing information dissemination including
summarized routing information
- support for multiple links between nodes (and allow for link and
node diversity)
- support architectural evolution in terms of the number of levels
of hierarchies, aggregation and segmentation of (control ?)
domains
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- support of routing attributes for links and nodes
4.1 Multiple Hierarchical Levels
TBD.
4.2 Hierarchical Routing Information Dissemination
TBD.
4.3 Multiple Links between Nodes
TBD.
4.4 Evolution
TBD.
4.5 Routing Attributes
TBD.
4.5.1 Link Attributes
TBD.
4.5.2 Node Attributes
TBD.
5. Backward Compatibility
TBD.
6. Security Considerations
TBD.
7. Acknowledgements
The authors would like to thank Kireeti Kompella for having
initiated the proposal of an ASON Routing Requirement Design Team.
8. References
[RFC 2026] S.Bradner, "The Internet Standards Process --
Revision 3", BCP 9, RFC 2026, October 1996.
[RFC 2119] S.Bradner, "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[G.7715] ITU-T Rec. G.7715/Y.1306, "Architecture and
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Requirements for the Automatically Switched Optical
Network (ASON)," June 2002.
[G.8080] ITU-T Rec. G.8080/Y.1304, "Architecture for the
Automatically Switched Optical Network (ASON),"
November 2001 (and Revision, January 2003).
9. Author's Addresses
Deborah Brungard (AT&T)
Rm. D1-3C22 - 200 S. Laurel Ave.
Middletown, NJ 07748, USA
Phone: +1 732 420 1573
E-mail: dbrungard@att.com
Dimitri Papadimitriou (Alcatel)
Francis Wellensplein 1,
B-2018 Antwerpen, Belgium
Phone : +32 3 240 8491
E-mail: dimitri.papadimitriou@alcatel.be
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Appendix - Terminology
This document makes use of the following terms:
Administrative domain: See Recommendation G.805.
Control plane: performs the call control and connection control
functions. Through signaling, the control plane sets up and releases
connections, and may restore a connection in case of a failure.
(Control) Domain: represents a collection of entities that are
grouped for a particular purpose. G.8080 applies this G.805
recommendation concept (that defines two particular forms, the
administrative domain and the management domain) to the control
plane in the form of a control domain. The entities that are grouped
in a control domain are components of the control plane.
External NNI (E-NNI): interfaces are located between protocol
controllers between control domains.
Internal NNI (I-NNI): interfaces are located between protocol
controllers within control domains.
Link: See Recommendation G.805.
Management plane: performs management functions for the Transport
Plane, the control plane and the system as a whole. It also provides
coordination between all the planes. The following management
functional areas are performed in the management plane: performance,
fault, configuration, accounting and security management
Management domain: See Recommendation G.805.
Transport plane: provides bi-directional or unidirectional transfer
of user information, from one location to another. It can also
provide transfer of some control and network management information.
The Transport Plane is layered; it is equivalent to the Transport
Network defined in G.805.
User Network Interface (UNI): interfaces are located between
protocol controllers between a user and a control domain.
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