Hi ASON Routing DT,
Please find attached a marked up copy of the draft.
All changes are typographical or nits.
Thanks,
Adrian
----- Original Message -----
From: "Kireeti Kompella" <kireeti@juniper.net>
To: <ccamp@ops.ietf.org>
Sent: Thursday, April 15, 2004 12:46 AM
Subject: Re: FW: I-D
ACTION:draft-ietf-ccamp-gmpls-ason-routing-reqts-03.txt
Hi All,
On Wed, 14 Apr 2004, Brungard, Deborah A, ALABS wrote:
> The ASON Routing Reqts DT has updated the following draft based on
> ITU Q14/15's Liaison and CCAMP mail list comments.
>
> We recommend this document as ready for WG Last Call.
This commences a two-week WG Last Call on the GMPLS ASON routing
requirements. Last Call ends April 28th, 5pm PDT. Please send your
comments to the list.
The proposed category is Informational.
Kireeti.
------------------------------------------------------------------------
CCAMP Working Group Wesam Alanqar (Sprint)
Internet Draft Deborah Brungard (ATT)
Category: Informational David Meyer (Cisco Systems)
Lyndon Ong (Ciena)
Expiration Date: October 2004 Dimitri Papadimitriou (Alcatel)
Jonathan Sadler (Tellabs)
Stephen Shew (Nortel)
April 2004
Requirements for Generalized MPLS (GMPLS) Routing
for Automatically Switched Optical Network (ASON)
draft-ietf-ccamp-gmpls-ason-routing-reqts-03.txt
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC-2026.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts. Internet-Drafts are draft documents valid for a maximum of
six months and may be updated, replaced, or obsoleted by other
documents at any time. It is inappropriate to use Internet- Drafts
as reference material or to cite them other than as "work in
progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
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
for an Automatically Switched Optical Network (ASON) as defined by
ITU-T.
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## Missing page throws
draft-ietf-ccamp-gmpls-ason-routing-reqts-03.txt April 2004
Table of Contents
Status of this Memo .............................................. 1
Abstract ......................................................... 1
1. Contributors .................................................. 2
2. Conventions used in this document ............................. 2
3. Introduction .................................................. 2
4. ASON Routing Architecture and Requirements .................... 4
4.1 Multiple Hierarchical Levels of ASON Routing Areas (RAs) ..... 5
4.2 Hierarchical Routing Information Dissemination ............... 5
4.3 Configuration ................................................ 7
4.3.1 Configuring the Multi-Level Hierarchy ...................... 7
4.3.2 Configuring RC Adjacencies ................................. 7
4.4 Evolution .................................................... 7
4.5 Routing Attributes ........................................... 8
4.5.1 Taxonomy of Routing Attributes ............................. 8
4.5.2 Commonly Advertised Information ............................ 9
4.5.3 Node Attributes ............................................ 9
4.5.4 Link Attributes ............................................ 9
5. Security Considerations ...................................... 11
6. Conclusions .................................................. 11
7. Acknowledgements ............................................. 13
8. Intellectual Property Considerations ......................... 13
8.1 IPR Disclosure Acknowledgement .............................. 13
9. References ................................................... 14
9.1 Normative References ........................................ 14
10. Author's Addresses .......................................... 14
Appendix 1: ASON Terminology .................................... 16
Appendix 2: ASON Routing Terminology ............................ 18
Full Copyright Statement ........................................ 19
1. Contributors
This document is the 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
[RFC2119].
3. Introduction
The GMPLS suite of protocols provides among other capabilities
support for controlling different switching technologies. These
include support for requesting TDM connections utilizing SONET/SDH
(see ANSI T1.105/ITU-T G.707) as well as Optical Transport Networks
(OTN, see ITU-T G.709). However, there are certain capabilities that
are needed to support the ITU-T G.8080 control plane architecture
for Automatically Switched Optical Network (ASON). Therefore, it is
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desirable to understand the corresponding requirements for the GMPLS
protocol suite. The ASON control plane architecture is defined in
[G.8080], ASON routing requirements are identified in [G.7715], and
in [G.7715.1] for ASON link state protocols. These Recommendations
apply to all G.805 layer networks (e.g. SDH and OTN), and provide
protocol neutral functional requirements and architecture.
This document focuses on the routing requirements for the GMPLS
suite of protocols to support the capabilities and functionality of
ASON control planes. This document summarizes the ASON requirements
using ASON terminology. This document does not address GMPLS
applicability or GMPLS capabilities. Any protocol (in particular,
routing) applicability, design or suggested extensions is strictly
outside the scope of this document. ASON (Routing) terminology
sections are provided in Appendix 1 and 2.
The ASON routing architecture is based on the following assumptions:
- A network is subdivided based on operator decision and criteria
(e.g. geography, administration, and/or technology), the network
subdivisions are defined in ASON as Routing Areas (RAs).
- The routing architecture and protocols applied after the network
is subdivided is an operator's choice. A multi-level hierarchy of
RAs, as defined in ITU-T [G.7715] and [G.7715.1], provides for a
hierarchical relationship of RAs based on containment, i.e. child
RAs are always contained within a parent RA. The hierarchical
containment relationship of RAs provides for routing information
abstraction, thereby enabling scalable routing information
representation. The maximum number of hierarchical RA levels to be
< supported is NOT specified (outside the scope).
supported is NOT specified (outside the scope of this document).
- Within an ASON RA and for each level of the routing hierarchy,
multiple routing paradigms (hierarchical, step- by-step, source-
based), centralized or distributed path computation, and multiple
different routing protocols MAY be supported. The architecture
does NOT assume a one-to-one correspondence of a routing protocol
and a RA level and allows the routing protocol(s) used within
different RAs (including child and parent RAs) to be different.
The realization of the routing paradigm(s) to support the
hierarchical levels of RAs is NOT specified.
- The routing adjacency topology (i.e. the associated Protocol
Controller (PC) connectivity) and transport topology is NOT
assumed to be congruent.
- The requirements support architectural evolution, e.g. a change in
the number of RA levels, as well as aggregation and segmentation
of RAs.
The description of the ASON routing architecture provides for a
conceptual reference architecture, with definition of functional
components and common information elements to enable end-to-end
routing in the case of protocol heterogeneity and facilitate
management of ASON networks. This description is only conceptual: no
physical partitioning of these functions is implied.
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4. ASON Routing Architecture and Requirements
## trivial: you have "a RA" also "an RP"
The fundamental architectural concept is the RA and it's related
functional components (see Appendix 2 on terminology). The routing
services offered by a RA are provided by a Routing Performer (RP).
An RP is responsible for a single RA, and it MAY be functionally
realized using distributed Routing Controllers (RC). The RC, itself,
MAY be implemented as a cluster of distributed entities (ASON refers
to the cluster as a Routing Control Domain (RCD)). The RC components
for a RA receive routing topology information from their associated
Link Resource Manager(s) (LRMs) and store this information in the
Routing Information Database (RDB). The RDB is replicated at each RC
< bounded to the same Routing Area (RA), and MAY contain information
bounded to the same RA, and MAY contain information
about multiple transport plane network layers. Whenever the routing
topology changes, the LRM informs the corresponding RC, which in
turn updates its associated RDB. In order to assure RDB
synchronization, the RCs co-operate and exchange routing
information. Path computation functions MAY exist in each RC, MAY
exist on selected RCs within the same RA, or MAY be centralized for
the RA.
In this context, communication between RCs within the same RA is
realized using a particular routing protocol (or multiple
protocols). In ASON, the communication component is represented by
the protocol controller (PC) component(s) and the protocol messages
are conveyed over the ASON control plane's Signaling Control Network
(SCN). The PC MAY convey information for one or more transport
network layers (refer to Section 4.2 Note). The RC is protocol
independent and RC communications MAY be realized by multiple,
different PCs within a RA.
The ASON routing architecture defines a multi-level routing
hierarchy of RAs based on a containment model to support routing
information abstraction. [G.7715.1] defines the ASON hierarchical
link state routing protocol requirements for communication of
routing information within an RA (one level) to support hierarchical
routing information dissemination (including summarized routing
information for other levels). The Communication between any of the
other functional component(s) (e.g. SCN, LRM, and between RCDs (RC-
RC communication between RAs)), is outside the scope of [G.7715.1]
protocol requirements and, thus, is also outside the scope of this
document.
ASON Routing components are identified by identifiers that are drawn
from different name spaces (see [G.7715.1]). These are control plane
identifiers for transport resources, components, and SCN addresses.
The formats of those identifiers in a routing protocol realization
SHALL be implementation specific and outside the scope of this
document.
The failure of a RC, or the failure of communications between RCs,
< and the subsequent recover from the failure condition MUST NOT
and the subsequent recovery from the failure condition MUST NOT
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disrupt calls in progress and their associated connections. Calls
being set up MAY fail to complete, and the call setup service MAY be
unavailable during recovery actions.
4.1 Multiple Hierarchical Levels of ASON Routing Areas (RAs)
[G.8080] introduces the concept of Routing Area (RA) in reference to
a network subdivision. RAs provide for routing information
abstraction. Except for the single RA case, RAs are hierarchically
contained: a higher level (parent) RA contains lower level (child)
RAs that in turn MAY also contain RAs, etc. Thus, RAs contain RAs
that recursively define successive hierarchical RA levels.
However, the RA containment relationship describes only an
architectural hierarchical organization of RAs. It does not restrict
a specific routing protocol's realization (e.g. OSPF multi-areas,
path computation, etc.). Moreover, the realization of the routing
paradigm to support a hierarchical organization of RAs and the
number of hierarchical RA levels to be supported is routing protocol
specific and outside the scope of this document.
In a multi-level hierarchy of RAs, it is necessary to distinguish
among RCs for the different levels of the RA hierarchy. Before any
pair of RCs establishes communication, they MUST verify they are
< bounded to the same parent RA (see Section 4.2). A RA identifier (RA
bound to the same parent RA (see Section 4.2). A RA identifier (RA
ID) is required to provide the scope within which the RCs can
< communicate. To distinguish between RCs bounded to the same RA, an
communicate. To distinguish between RCs bound to the same RA, an
RC identifier (RC ID) is required; the RC ID MUST be unique within
its containing RA.
< A RA represents a partition of the data plane and its identifier
A RA represents a partition of the data plane, and its identifier
(i.e. RA ID) is used within the control plane as a reference to the
< data plane partition. Each RA SHALL be uniquely identifiable within
< a carrier's network. RA IDs MAY be associated with a transport plane
data plane partition. Each RA within a carrier's network SHALL be
uniquely identifiable. RA IDs MAY be associated with a transport plane
name space whereas RC IDs are associated with a control plane name
space.
4.2 Hierarchical Routing Information Dissemination
< Routing information can be exchanged between RCs bounded to adjacent
Routing information can be exchanged between RCs bound to adjacent
levels of the RA hierarchy i.e. Level N+1 and N, where Level N
represents the RAs contained by Level N+1. The links connecting RAs
MAY be viewed as external links (inter-RA links), and the links
representing connectivity within a RA MAY be viewed as internal
links (intra-RA links). The external links to a RA at one level of
the hierarchy may be internal links in the parent RA. Intra-RA links
of a child RA MAY be hidden from the parent RA's view.
The physical location of RCs for adjacent RA levels, their
relationship and their communication protocol(s) are outside the
scope of this document. No assumption is made regarding how RCs
communicate between adjacent RA levels. If routing information is
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exchanged between a RC, its parent, and its child RCs, it SHOULD
include reachability and MAY include (upon policy decision) node and
< link topology. Only the RCs of the parent RA communicate, RCs of one
< childÆs RA never communicate with the RCs of other child RAs. There
link topology. Communication between RAs only takes place between
RCs with a parent/child relationship. RCs of one RA never communicate
with RCs of another RA at the same level. There
SHOULD not be any dependencies on the different routing protocols
used within a RA or in different RAs.
< Multiple RCs bounded to the same RA MAY transform (filter,
Multiple RCs bound to the same RA MAY transform (filter,
summarize, etc.) and then forward information to RCs at different
levels. However in this case the resulting information at the
receiving level must be self-consistent; this MAY be achieved using
a number of mechanisms.
Note: there is no implied relationship between multi-layer transport
networks and multi-level routing. Implementations may support a
hierarchical routing topology (multi-level) with a single routing
protocol instance for multiple transport switching layers or a
hierarchical routing topology for one transport switching layer.
1. Type of Information Exchanged
The type of information flowing upward (i.e. Level N to Level
N+1) and the information flowing downward (i.e. Level N+1 to
Level N) are used for similar purposes, namely, the exchange of
reachability information and summarized topology information to
allow routing across multiple RAs. The summarization of topology
information may impact the accuracy of routing and MAY require
additional path calculation.
< The following information exchange are expected:
The following information exchanges are expected:
- Level N+1 visibility to Level N reachability and topology (or
upward information communication) allowing RC(s) at Level N+1
to determine the reachable endpoints from Level N.
- Level N visibility to Level N+1 reachability and topology (or
downward information communication) allowing RC(s) bounded to a
RA at Level N to develop paths to reachable endpoints outside
of the RA.
2. Interactions between Upward and Downward Communication
When both upward and downward information exchanges contain
endpoint reachability information, a feedback loop could
potentially be created. Consequently, the routing protocol MUST
include a method to:
- prevent information propagated from a Level N+1 RA's RC into
< the Level N RA's RC to be re-introduced into the Level N+1 RA's
< RC, and
the Level N RA's RC from being re-introduced into the Level N+1
RA's RC, and
- prevent information propagated from a Level N-1 RA's RC into
< the Level N RA's RC to be re-introduced into the Level N-1 RA's
the Level N RA's RC from being re-introduced into the Level N-1 RA's
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RC.
The routing protocol SHALL differentiate the routing information
originated at a given level RA from derived routing information
(received from external RAs), even when this information is
forwarded by another RC at the same level. This is a necessary
condition to be fulfilled by routing protocols to be loop free.
3. Method of Communication
Two approaches exist for communication between Level N and N+1.
- The first approach places an instance of a Level N routing
function and an instance of a Level N+1 routing function in the
same system. The communications interface is within a single
system and is thus not an open interface subject to
standardization.
- The second approach places the Level N routing function on a
separate system from the Level N+1 routing function. In this
case, a communication interface must be used between the
systems containing the routing functions for different levels.
This communication interface and mechanisms are outside the
scope of this document.
4.3 Configuration
4.3.1 Configuring the Multi-Level Hierarchy
The RC MUST support static (i.e. operator assisted) and MAY support
automated configuration of the information describing its
< relationship to parent and its child within the hierarchical
relationship to its parent and its children within the hierarchical
structure (including RA ID and RC ID). When applied recursively, the
whole hierarchy is thus configured.
4.3.2 Configuring RC Adjacencies
The RC MUST support static (i.e. operator assisted) and MAY support
automated configuration of the information describing its associated
PC adjacencies to other RCs bounded to the same parent RA. The
< PC adjacencies to other RCs bound to the same parent RA. The
## Do you really mean PC or RC?
routing protocol SHOULD support all the types of RC adjacencies
described in Section 9 of [G.7715]. The latter includes congruent
topology (with distributed RC) and hubbed topology (e.g. note that
the latter does not automatically imply designated RC).
4.4 Evolution
The containment relationships of RAs MAY change, motivated by events
such as mergers, acquisitions, and divestitures.
The routing protocol SHOULD be capable of supporting architectural
evolution in terms of number of hierarchical levels of RAs, as well
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< as aggregation and segmentation of RAs. RA IDs uniqueness within an
as aggregation and segmentation of RAs. RA ID uniqueness within an
administrative domain MAY facilitate these operations. The routing
protocol is not expected to automatically initiate and/or execute
these operations. Reconfiguration of the RA hierarchy MAY not
## Surely this is MUST?
disrupt calls in progress, though calls being set up may fail to
complete, and the call setup service may be unavailable during
reconfiguration actions.
4.5 Routing Attributes
Routing for transport networks is performed on a per layer basis,
where the routing paradigms MAY differ among layers and within a
< layer. Not all equipment support the same set of transport layers or
layer. Not all equipment supports the same set of transport layers or
the same degree of connection flexibility at any given layer. A
server layer trail may support various clients, involving different
adaptation functions. Additionally, equipment may support variable
adaptation functionality, whereby a single server layer trail
dynamically supports different multiplexing structures. As a result,
routing information MAY include layer specific, layer independent,
and client/server adaptation information.
4.5.1 Taxonomy of Routing Attributes
Attributes can be organized according to the following categories:
- Node related or link related
- Provisioned, negotiated or automatically configured
- Inherited or layer specific (client layers can inherit some
attributes from the server layer while other attributes like
Link Capacity are specified by layer).
(Component) link attributes MAY be statically or automatically
configured for each transport network layer. This may lead to
unnecessary repetition. Hence, the inheritance property of
attributes MAY also be used to optimize the configuration process.
< ASON uses the term, SNP, for the control plane representation of a
ASON uses the term, Subnetwork Point (SNP), for the control plane representation of a
transport plane resource. The control plane representation and
transport plane topology is NOT assumed to be congruent, the control
plane representation SHALL not be restricted by the physical
topology. The relational grouping of SNPs for routing is termed a
< SNPP. The routing function understands topology in terms of SNPP
SNP Pool (SNPP). The routing function understands topology in terms of SNPP
links. Grouping MAY be based on different link attributes (e.g.,
SRLG information, link weight, etc).
Two RAs may be linked by one or more SNPP links. Multiple SNPP links
MAY be required when component links are not equivalent for routing
purposes with respect to the RAs they are attached to, or to the
containing RA, or when smaller groupings are required.
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4.5.2 Commonly Advertised Information
Advertisements MAY contain the following common set of information
regardless of whether they are link or node related:
< - RA ID of which the advertisement is bounded
- RA ID of the RA to which the advertisement is bound
- RC ID of the entity generating the advertisement
- Information to uniquely identify advertisements
- Information to determine whether an advertisement has been updated
- Information to indicate when an advertisement has been derived
from a different level RA.
4.5.3 Node Attributes
All nodes belong to a RA, hence, the RA ID can be considered an
attribute of all nodes. Given that no distinction is made between
abstract nodes and those that cannot be decomposed any further, the
same attributes MAY be used for their advertisement. In the
< following tables, Capability refers to level of support required in
following tables, Capability refers to the level of support required in
the realization of a link state routing protocol, whereas Usage
< refers to degree of operational and implementation flexibility.
refers to the degree of operational and implementation flexibility.
The following Node Attributes are defined:
Attribute Capability Usage
----------- ----------- ---------
Node ID REQUIRED REQUIRED
Reachability REQUIRED OPTIONAL
Table 1. Node Attributes
Reachability information describes the set of endpoints that are
reachable by the associated node. It MAY be advertised as a set of
associated external (e.g. UNI) address/address prefixes or a set of
associated SNPP link IDs/SNPP ID prefixes, the selection of which
MUST be consistent within the applicable scope. These are control
plane identifiers, the formats of these identifiers in a protocol
realization is implementation specific and outside the scope of this
document.
Note: no distinction is made between nodes that may have further
internal details (i.e., abstract nodes) and those that cannot be
< decomposed any further. Hence the attributes of a node are not be
decomposed any further. Hence the attributes of a node are not
considered only as single switch attributes but MAY apply to a node
at a higher level of the hierarchy that represents a sub-network.
4.5.4 Link Attributes
The following Link Attributes are defined:
Link Attribute Capability Usage
--------------- ----------- ---------
Local SNPP link ID REQUIRED REQUIRED
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Remote SNPP link ID REQUIRED REQUIRED
Layer Specific Characteristics see Table 3
Table 2. Link Attributes
The SNPP link ID name MUST be sufficient to uniquely identify the
## Why do you say "SNPP link ID name"? This is not defined.
## Do you mean "SNPP link ID"?
corresponding transport plane resource taking into account
separation of data and control planes (see Section 4.5.1, the
control plane representation and transport plane topology is not
assumed to be congruent). The SNPP link ID format is routing
protocol specific.
Note: when the remote end of a SNPP link is located outside of the
RA, the remote SNPP link ID is OPTIONAL.
The following link characteristic attributes are defined:
- Signal Type: This identifies the characteristic information of the
layer network.
- Link Weight: The metric indicating the relative desirability of a
particular link over another e.g. during path computation.
- Resource Class: This corresponds to the set of administrative
groups assigned by the operator to this link. A link MAY belong to
zero, one or more administrative groups.
- Connection Types: This attribute identifies whether the local SNP
represents a TCP, CP, or can be flexibly configured as a TCP.
## Please expand TCP and CP in their first uses
- Link Capacity: This provides the sum of the available and
potential bandwidth capacity for a particular network transport
layer. Other capacity measures MAY be further considered.
- Link Availability: This represents the survivability capability
such as the protection type associated with the link.
- Diversity Support: This represents diversity information such as
the SRLG information associated with the link.
- Local Adaptation Support: This indicates the set of client layer
adaptations supported by the TCP associated with the Local SNPP.
This is only applicable when the local SNP represents a TCP or can
be flexibly configured as a TCP.
Link Characteristics Capability Usage
----------------------- ---------- ---------
Signal Type REQUIRED OPTIONAL
Link Weight REQUIRED OPTIONAL
Resource Class REQUIRED OPTIONAL
Local Connection Types REQUIRED OPTIONAL
Link Capacity REQUIRED OPTIONAL
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Link Availability OPTIONAL OPTIONAL
Diversity Support OPTIONAL OPTIONAL
Local Adaptation support OPTIONAL OPTIONAL
Table 3. Link Characteristics
Note: separate advertisements of layer specific attributes MAY be
< chosen. However this may lead to unnecessary duplication. This can
chosen. However, this may lead to unnecessary duplication. This can
be avoided using the inheritance property, so that the attributes
derivable from the local adaptation information do not need to be
advertised. Thus, an optimization MAY be used when several layers
are present by indicating when an attribute is inheritable from a
server layer.
5. Security Considerations
ASON routing protocol MUST deliver the operational security
objectives where required. These objectives do not necessarily imply
requirements on the routing protocol itself, and MAY be met by other
established means.
6. Conclusions
The description of the ASON routing architecture and components is
provided in terms of routing functionality. This description is only
conceptual: no physical partitioning of these functions is implied.
In summary, the ASON routing architecture assumes:
- A network is subdivided into ASON RAs, which MAY support multiple
routing protocols, no one-to-one relationship SHALL be assumed
- Routing Controllers (RC) provide for the exchange of routing
information (primitives) for the RA. The RC is protocol
independent and MAY be realized by multiple, different protocol
controllers within a RA. The routing information exchanged between
RCs SHALL be subject to policy constraints imposed at reference
points (External- and Internal-NNI)
< - A multi-level RA hierarchy based on containment, only the RCs of
< the parent RA communicate. RCs of child RAs never communicate with
- In a multi-level RA hierarchy based on containment, communication
between RCs of different RAs only happens when there is a parent/
child relationship between the RAs. RCs of child RAs never communicate with
the RCs of other child RAs. There SHOULD not be any dependencies
on the different routing protocols used within a child RA and that
of its parent. The routing information exchanged within the parent
RA SHALL be independent of both the routing protocol operating
within a child RA, and any control distribution choice(s), e.g.
centralized, fully distributed.
- For a RA, the set of RCs is referred to as an ASON routing
(control) domain. The routing information exchanged between
routing domains (inter-RA, i.e. inter-domain) SHALL be independent
of both the intra-domain routing protocol(s), and the intra-domain
control distribution choice(s), e.g. centralized, fully
distributed. RCs bounded to different RA levels MAY be co-located
within the same physical element or physically distributed.
- The routing adjacency topology (i.e. the associated PC
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connectivity topology) and the transport network topology SHALL
NOT be assumed to be congruent
- The routing topology SHALL support multiple links between nodes
and RAs
In summary, the following functionality is expected from GMPLS
routing to instantiate the ASON hierarchical routing architecture
realization (see [G.7715] and [G.7715.1]):
- RAs SHALL be uniquely identifiable within a carrier's network,
each having a unique RA ID within the carrier's network.
- Within a RA (one level), the routing protocol SHALL support
dissemination of hierarchical routing information (including
summarized routing information for other levels) in support of an
architecture of multiple hierarchical levels of RAs; the number of
hierarchical RA levels to be supported by a routing protocol is
implementation specific.
- The routing protocol SHALL support routing information based on a
common set of information elements as defined in [G.7715] and
[G.7715.1], divided between attributes pertaining to links and
abstract nodes (each representing either a sub-network or simply a
node). [G.7715] recognizes that the manner in which the routing
information is represented and exchanged will vary with the
routing protocol used.
- The routing protocol SHALL converge such that the distributed RDBs
become synchronized after a period of time.
To support hierarchical routing information dissemination within an
RA, the routing protocol MUST deliver:
< - processing of routing information exchanged between adjacent
- Processing of routing information exchanged between adjacent
levels of the hierarchy (i.e. Level N+1 and N) including
reachability and upon policy decision summarized topology
information
< - when multiple RCs bound to a RA transform (filter, summarize,
< etc.) and then forward information to RC(s) at different levels
< that the resulting information at the receiving level is self-
< consistent
- Self-consistent information at the receiving level resulting from
any transformation (filter, summarize, etc.) and forwarding of
information from one RC to RC(s) at different levels when multiple
RCs bound to a single RA
< - a mechanism to prevent re-introduction of information propagated
- A mechanism to prevent re-introduction of information propagated
into the Level N RA's RC back to the adjacent level RA's RC from
which this information has been initially received.
In order to support operator assisted changes in the containment
relationships of RAs, the routing protocol SHALL support evolution
< in terms of number of hierarchical levels of RAs. Example: support
in terms of number of hierarchical levels of RAs. For example: support
of non-disruptive operations such as adding and removing RAs at the
top/bottom of the hierarchy, adding or removing a hierarchical level
of RAs in or from the middle of the hierarchy, as well as
aggregation and segmentation of RAs. The number of hierarchical
levels to be supported is routing protocol specific, and reflects a
containment relationship e.g. a RA insertion involves supporting a
different routing protocol domain in a portion of the network.
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Reachability information (see Section 4.5.3) of the set of endpoints
reachable by a node may be advertised either as a set of UNI
Transport Resource addresses/ address prefixes, or a set of
associated SNPP link IDs/SNPP link ID prefixes, assigned and
selected consistently in their applicability scope. The formats of
the control plane identifiers in a protocol realization are
implementation specific. Use of a routing protocol within a RA
should not restrict the choice of routing protocols for use in other
RAs (child or parent).
As ASON does not restrict the control plane architecture choice
used, either a co-located architecture or a physically separated
architecture may be used. A collection of links and nodes such as a
sub-network or RA MUST be able to represent itself to the wider
network as a single logical entity with only its external links
visible to the topology database.
7. Acknowledgements
The authors would like to thank Kireeti Kompella for having
initiated the proposal of an ASON Routing Requirement Design Team.
## Perhaps it would be good to acknowledge any other contributors you had.
## In particular SG14/15 for their careful review and input.
8. Intellectual Property Considerations
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.
8.1 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.
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9. References
9.1 Normative References
[RFC2026] S.Bradner, "The Internet Standards Process --
Revision 3", BCP 9, RFC 2026, October 1996.
[RFC2119] 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
Requirements for the Automatically Switched Optical
Network (ASON)," June 2002.
[G.7715.1] ITU-T Draft Rec. G.7715.1/Y.1706.1, "ASON Routing
Architecture and Requirements for Link State
Protocols," November 2003.
[G.8080] ITU-T Rec. G.8080/Y.1304, "Architecture for the
Automatically Switched Optical Network (ASON),"
November 2001 (and Revision, January 2003).
[HIER] K.Kompella and Y.Rekhter, "LSP Hierarchy with
Generalized MPLS TE," Internet draft (work in
progress), draft-ietf-mpls-lsp-hierarchy, September 02.
## Would it be OK to make the external references informative?
10. Author's Addresses
Wesam Alanqar (Sprint)
EMail: wesam.alanqar@mail.sprint.com
Deborah Brungard (AT&T)
Rm. D1-3C22 - 200 S. Laurel Ave.
Middletown, NJ 07748, USA
Phone: +1 732 4201573
EMail: dbrungard@att.com
David Meyer (Cisco Systems)
EMail: dmm@1-4-5.net
Lyndon Ong (Ciena Corporation)
5965 Silver Creek Valley Rd,
San Jose, CA 95128, USA
Phone: +1 408 8347894
EMail: lyong@ciena.com
Dimitri Papadimitriou (Alcatel)
Francis Wellensplein 1,
B-2018 Antwerpen, Belgium
Phone: +32 3 2408491
EMail: dimitri.papadimitriou@alcatel.be
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Jonathan Sadler
1415 W. Diehl Rd
Naperville, IL 60563
EMail: jonathan.sadler@tellabs.com
Stephen Shew (Nortel Networks)
PO Box 3511 Station C
Ottawa, Ontario, CANADA K1Y 4H7
Phone: +1 613 7632462
EMail: sdshew@nortelnetworks.com
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Appendix 1: ASON Terminology
This document makes use of the following terms:
Administrative domain: (Recommendation G.805 For the purposes of
[G7715.1] an administrative domain represents the extent of
resources which belong to a single player such as a network
operator, a service provider, or an end-user. Administrative domains
of different players do not overlap amongst themselves.
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 (control) entities that
are grouped for a particular purpose. The control plane is
subdivided into domains matching administrative domains. Within an
administrative domain, further subdivisions of the control plane are
recursively applied. A routing control domain is an abstract entity
that hides the details of the RC distribution.
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] a "topological component" which
describes a fixed relationship between a "subnetwork" or "access
group" and another "subnetwork" or "access group". Links are not
limited to being provided by a single server trail.
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] A management domain
defines a collection of managed objects which are grouped to meet
organizational requirements according to geography, technology,
policy or other structure, and for a number of functional areas such
as configuration, security, (FCAPS), for the purpose of providing
control in a consistent manner. Management domains can be disjoint,
contained or overlapping. As such the resources within an
administrative domain can be distributed into several possible
overlapping management domains. The same resource can therefore
belong to several management domains simultaneously, but a
management domain shall not cross the border of an administrative
domain.
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SNP: The SNP is a control plane abstraction that represents an
actual or potential transport plane resource. SNPs (in different
subnetwork partitions) may represent the same transport resource. A
one-to-one correspondence should not be assumed.
## Add SNPP
## Add TCP
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. Note:
there is no routing function associated with a UNI reference point.
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Appendix 2: ASON Routing Terminology
This document makes use of the following terms:
Routing Area (RA): a RA represents a partition of the data plane and
its identifier is used within the control plane as the
representation of this partition. Per [G.8080] a RA is defined by a
set of sub-networks, the TE links that interconnect them, and the
interfaces representing the ends of the TE links exiting that RA. A
RA may contain smaller RAs inter-connected by TE links. The limit of
subdivision results in a RA that contains two sub-networks and a TE
link with a single component link.
Routing Database (RDB): repository for the local topology, network
topology, reachability, and other routing information that is
updated as part of the routing information exchange and may
additionally contain information that is configured. The RDB may
contain routing information for more than one Routing Area (RA).
Routing Components: ASON routing architecture functions. These
functions can be classified as protocol independent (Link Resource
Manager or LRM, Routing Controller or RC) and protocol specific
(Protocol Controller or PC).
Routing Controller (RC): handles (abstract) information needed for
routing and the routing information exchange with peering RCs by
operating on the RDB. The RC has access to a view of the RDB. The RC
is protocol independent.
Note: Since the RDB may contain routing information pertaining to
multiple RAs (and possibly to multiple layer networks), the RCs
accessing the RDB may share the routing information.
Link Resource Manager (LRM): supplies all the relevant component and
TE link information to the RC. It informs the RC about any state
changes of the link resources it controls.
Protocol Controller (PC): handles protocol specific message
exchanges according to the reference point over which the
information is exchanged (e.g. E-NNI, I-NNI), and internal exchanges
with the RC. The PC function is protocol dependent.
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Full Copyright Statement
## Require new copyright boilerplate
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