A Framework for QoS-based Routing in the Internet
RFC 2386
Network Working Group E. Crawley
Request for Comments: 2386 Argon Networks
Category: Informational R. Nair
Arrowpoint
B. Rajagopalan
NEC USA
H. Sandick
Bay Networks
August 1998
A Framework for QoS-based Routing in the Internet
Status of this Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (1998). All Rights Reserved.
ABSTRACT
QoS-based routing has been recognized as a missing piece in the
evolution of QoS-based service offerings in the Internet. This
document describes some of the QoS-based routing issues and
requirements, and proposes a framework for QoS-based routing in the
Internet. This framework is based on extending the current Internet
routing model of intra and interdomain routing to support QoS.
1. SCOPE OF DOCUMENT & PHILOSOPHY
This document proposes a framework for QoS-based routing, with the
objective of fostering the development of an Internet-wide solution
while encouraging innovations in solving the many problems that
arise. QoS-based routing has many complex facets and it is
recommended that the following two-pronged approach be employed
towards its development:
1. Encourage the growth and evolution of novel intradomain QoS-based
routing architectures. This is to allow the development of
independent, innovative solutions that address the many QoS-based
routing issues. Such solutions may be deployed in autonomous
systems (ASs), large and small, based on their specific needs.
Crawley, et. al. Informational [Page 1]
RFC 2386 A Framework for QoS-based Routing August 1998
2. Encourage simple, consistent and stable interactions between ASs
implementing routing solutions developed as above.
This approach follows the traditional separation between intra and
interdomain routing. It allows solutions like QOSPF [GKOP98, ZSSC97],
Integrated PNNI [IPNNI] or other schemes to be deployed for
intradomain routing without any restriction, other than their ability
to interact with a common, and perhaps simple, interdomain routing
protocol. The need to develop a single, all encompassing solution to
the complex problem of QoS-based routing is therefore obviated. As a
practical matter, there are many different views on how QoS-based
routing should be done. Much overall progress can be made if an
opportunity exists for various ideas to be developed and deployed
concurrently, while some consensus on the interdomain routing
architecture is being developed. Finally, this routing model is
perhaps the most practical from an evolution point of view. It is
superfluous to say that the eventual success of a QoS-based Internet
routing architecture would depend on the ease of evolution.
The aim of this document is to describe the QoS-based routing issues,
identify basic requirements on intra and interdomain routing, and
describe an extension of the current interdomain routing model to
support QoS. It is not an objective of this document to specify the
details of intradomain QoS-based routing architectures. This is left
up to the various intradomain routing efforts that might follow. Nor
is it an objective to specify the details of the interface between
reservation protocols such as RSVP and QoS-based routing. The
specific interface functionality needed, however, would be clear from
the intra and interdomain routing solutions devised. In the
intradomain area, the goal is to develop the basic routing
requirements while allowing maximum freedom for the development of
solutions. In the interdomain area, the objectives are to identify
the QoS-based routing functions, and facilitate the development or
enhancement of a routing protocol that allows relatively simple
interaction between domains.
In the next section, a glossary of relevant terminology is given. In
Section 3, the objectives of QoS-based routing are described and the
issues that must be dealt with by QoS-based Internet routing efforts
are outlined. In Section 4, some requirements on intradomain routing
are defined. These requirements are purposely broad, putting few
constraints on solution approaches. The interdomain routing model and
issues are described in Section 5 and QoS-based multicast routing is
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