Integration of Real-time Services in an IP-ATM Network Architecture
RFC 1821
|
Document |
Type |
|
RFC - Informational
(August 1995; No errata)
|
|
Authors |
|
|
|
Last updated |
|
2013-03-02
|
|
Stream |
|
Legacy
|
|
Formats |
|
plain text
html
pdf
htmlized
bibtex
|
Stream |
Legacy state
|
|
(None)
|
|
Consensus Boilerplate |
|
Unknown
|
|
RFC Editor Note |
|
(None)
|
IESG |
IESG state |
|
RFC 1821 (Informational)
|
|
Telechat date |
|
|
|
Responsible AD |
|
(None)
|
|
Send notices to |
|
(None)
|
Network Working Group M. Borden
Request for Comments: 1821 E. Crawley
Category: Informational Bay Networks
B. Davie
Bellcore
S. Batsell
NRL
August 1995
Integration of Real-time Services in an IP-ATM Network Architecture
Status of the Memo
This memo provides information for the Internet community. This memo
does not specify an Internet standard of any kind. Distribution of
this memo is unlimited.
Abstract
The IETF is currently developing an integrated service model which is
designed to support real-time services on the Internet.
Concurrently, the ATM Forum is developing Asynchronous Transfer Mode
networking which similarly provides real-time networking support. The
use of ATM in the Internet as a link layer protocol is already
occurring, and both the IETF and the ATM Forum are producing
specifications for IP over ATM. The purpose of this paper is to
provide a clear statement of what issues need to be addressed in
interfacing the IP integrated services environment with an ATM
service environment so as to create a seamless interface between the
two in support of end users desiring real-time networking services.
Table of Contents
1.0 Introduction 2
2.0 Problem Space Overview 3
2.1 Initial Assumptions 3
2.2 Topologies Under Consideration 4
2.3 Providing QoS in IP over ATM - a walk-though 5
3.0 Service Model Issues 6
3.1 Traffic Characterization 7
3.2 QoS Characterization 8
4.0 Resource Reservation Styles 10
4.1 RSVP 10
4.2 ST-II 13
4.3 Mapping IP flows to ATM Connections 15
5.0 End System Issues 16
6.0 Routing Issues 16
Borden, et al Informational [Page 1]
RFC 1821 Real-time Service in IP-ATM Networks August 1995
6.1 Multicast routing 17
6.2 QoS Routing 17
6.3 Mobile Routing 18
7.0 Security Issues 19
8.0 Future Directions 20
9.0 References 22
10.0 Authors' Addresses 24
1.0 Introduction
The traditional network service on the Internet is best-effort
datagram transmission. In this service, packets from a source are
sent to a destination, with no guarantee of delivery. For those
applications that require a guarantee of delivery, the TCP protocol
will trade packet delay for correct reception by retransmitting those
packets that fail to reach the destination. For traditional
computer-communication applications such as FTP and Telnet in which
correct delivery is more important than timeliness, this service is
satisfactory. However, a new class of application which uses multiple
media (voice, video, and computer data) has begun to appear on the
Internet. Examples of this class of application are video
teleconferencing, video-on-demand, and distributed simulation. While
these applications can operate to some extent using best-effort
delivery, trading packet delay for correct reception is not an
acceptable trade-off. Operating in the traditional mode for these
applications results in reduced quality of the received information
and, potentially, inefficient use of bandwidth. To remedy this
problem the IETF is developing a real-time service environment in
which multiple classes of service are offered [6]. This environment
will greatly extend the existing best-effort service model to meet
the needs of multimedia applications with real-time constraints.
At the same time that this effort is underway in the IETF,
Asynchronous Transfer Mode (ATM) is being developed, initially as a
replacement for the current telephone network protocols, but more
recently as a link-layer protocol for computer communications. As it
was developed from the beginning with telephone voice applications in
Show full document text