Network Working Group K. Dubray
Request for Comments: 2432 IronBridge Networks
Category: Informational October 1998
Terminology for IP Multicast Benchmarking
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 (C) The Internet Society (1998). All Rights Reserved.
The purpose of this document is to define terminology specific to the
benchmarking of multicast IP forwarding devices. It builds upon the
tenets set forth in RFC 1242, RFC 2285, and other IETF Benchmarking
Methodology Working Group (BMWG) efforts. This document seeks to
extend these efforts to the multicast paradigm.
The BMWG produces two major classes of documents: Benchmarking
Terminology documents and Benchmarking Methodology documents. The
Terminology documents present the benchmarks and other related terms.
The Methodology documents define the procedures required to collect
the benchmarks cited in the corresponding Terminology documents.
Network forwarding devices are being required to take a single frame
and support delivery to a number of destinations having membership to
a particular group. As such, multicast support may place a different
burden on the resources of these network forwarding devices than with
unicast or broadcast traffic types.
Such burdens may not be readily apparent at first glance - the IP
multicast packet's Class D address may be the only noticeable
difference from an IP unicast packet. However, there are many
factors that may impact the treatment of IP multicast packets.
Consider how a device's architecture may impact the handling of a
multicast frame. For example, is the multicast packet subject to the
same processing as its unicast analog? Or is the multicast packet
treated as an exeception and processed on a different data path?
Dubray Informational [Page 1]RFC 2432 Terminology for IP Multicast Benchmarking October 1998
Consider, too, how a shared memory architecture may demonstrate a
different performance profile than an architecture which explicitly
passes each individual packet between the processing entities.
In addition to forwarding device architecture, there are other
factors that may impact a device's or system's multicast related
performance. Protocol requirements may demand that routers and
switches consider destination and source addressing in its multicast
forwarding decisions. Capturing multicast source/destination
addressing information may impact forwarding table size and lengthen
lookups. Topological factors such as the degree of packet
replication, the number of multicast groups being supported by the
system, or the placement of multicast packets in unicast wrappers to
span non-multicast network paths may all potentially affect a
system's multicast related performance. For an overall understanding
of IP multicasting, the reader is directed to [Se98], [Hu95], and
By clearly identifying IP multicast benchmarks and related
terminology in this document, it is hoped that detailed methodologies
can be generated in subsequent documents. Taken in tandem, these two
efforts endeavor to assist the clinical, empirical, and consistent
characterization of certain aspects of multicast technologies and
their individual implementations. Understanding the operational
profile of multicast forwarding devices may assist the network
designer to better deploy multicast in his or her networking
Moreover, this document focuses on one source to many destinations
profiling. Elements of this document may require extension when
considering multiple source to multiple destination IP multicast
2. Definition Format
This section cites the template suggested by RFC 1242 in the
specification of a term to be defined.
Term to be defined.
The specific definition for the term.
A brief discussion of the term, its application, or other
information that would build understanding.
Dubray Informational [Page 2]RFC 2432 Terminology for IP Multicast Benchmarking October 1998
Units used to record measurements of this term, if applicable.
List of issues or conditions that affect this term. This field can