A Framework for QoS-based Routing in the Internet
RFC 2386

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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