RFC 3754 (rfc3754) - Page 2 of 34
IP Multicast in Differentiated Services (DS) Networks
Alternative Format: Original Text Document
RFC 3754 IP Multicast in DS Networks April 2004
9.1. Simulation Scenario. . . . . . . . . . . . . . . . . . . 24
9.2. Simulation Results for Different Router Types. . . . . . 26
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 31
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 31
11.1. Normative References . . . . . . . . . . . . . . . . . . 31
11.2. Informative References . . . . . . . . . . . . . . . . . 31
12. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 33
13. Full Copyright Statement . . . . . . . . . . . . . . . . . . . 34
1. Introduction
This document discusses the problems of IP Multicast use in
Differentiated Services (DS) networks, expanding on the discussion in
RFC 2475 ("An Architecture of Differentiated Services"). It also
suggests possible solutions to these problems, describes a potential
implementation model, and presents simulation results.
The "Differentiated Services" (DiffServ or DS) approach [1, 2, 3]
defines certain building blocks and mechanisms to offer qualitatively
better services than the traditional best-effort delivery service in
an IP network. In the DiffServ Architecture [2], scalability is
achieved by avoiding complexity and maintenance of per-flow state
information in core nodes, and by pushing unavoidable complexity to
the network edges. Therefore, individual flows belonging to the same
service are aggregated, thereby eliminating the need for complex
classification or managing state information per flow in interior
nodes.
On the other hand, the reduced complexity in DS nodes makes it more
complex to use those "better" services together with IP Multicast
(i.e., point-to-multipoint or multipoint-to-multipoint
communication). Problems emerging from this fact are described in
section 2. Although the basic DS forwarding mechanisms also work
with IP Multicast, some facts have to be considered which are related
to the provisioning of multicast resources. It is important to
integrate IP Multicast functionality into the architecture from the
beginning, and to provide simple solutions for those problems that
will not defeat the already gained advantages.
1.1. Management of Differentiated Services
At least for Per-Domain Behaviors and services based on the EF PHB,
admission control and resource reservation are required [14, 15].
Installation and updating of traffic profiles in boundary nodes is
necessary. Most network administrators cannot accomplish this task
manually, even for long term service level agreements (SLAs).
Furthermore, offering services on demand requires some kind of
signaling and automatic admission control procedures.
Bless & Wehrle Informational