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PPP in a Real-time Oriented HDLC-like Framing (RFC2687)

IP.com Disclosure Number: IPCOM000003279D
Original Publication Date: 1999-Sep-01
Included in the Prior Art Database: 2000-Sep-13
Document File: 11 page(s) / 27K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

C. Bormann: AUTHOR

Abstract

A companion document describes an architecture for providing integrated services over low-bitrate links, such as modem lines, ISDN B-channels, and sub-T1 links [1]. The main components of the architecture are: a real-time encapsulation format for asynchronous and synchronous low-bitrate links, a header compression architecture optimized for real-time flows, elements of negotiation protocols used between routers (or between hosts and routers), and announcement protocols used by applications to allow this negotiation to take place.

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Network Working Group C. Bormann

Request for Comments: 2687 Universitaet Bremen TZI

Category: Standards Track September 1999

PPP in a Real-time Oriented HDLC-like Framing

Status of this Memo

This document specifies an Internet standards track protocol for the

Internet community, and requests discussion and suggestions for

improvements. Please refer to the current edition of the "Internet

Official Protocol Standards" (STD 1) for the standardization state

and status of this protocol. Distribution of this memo is unlimited.

Copyright Notice

Copyright (C) The Internet Society (1999). All Rights Reserved.

Abstract

A companion document describes an architecture for providing

integrated services over low-bitrate links, such as modem lines, ISDN

B-channels, and sub-T1 links [1]. The main components of the

architecture are: a real-time encapsulation format for asynchronous

and synchronous low-bitrate links, a header compression architecture

optimized for real-time flows, elements of negotiation protocols used

between routers (or between hosts and routers), and announcement

protocols used by applications to allow this negotiation to take

place.

This document proposes the suspend/resume-oriented solution for the

real-time encapsulation format part of the architecture. The general

approach is to start from the PPP Multilink fragmentation protocol

[2] and its multi-class extension [5] and add suspend/resume in a way

that is as compatible to existing hard- and firmware as possible.

1. Introduction

As an extension to the "best-effort" services the Internet is well-

known for, additional types of services ("integrated services") that

support the transport of real-time multimedia information are being

developed for, and deployed in the Internet.

The present document defines the suspend/resume-oriented solution for

the real-time encapsulation format part of the architecture. As

described in more detail in the architecture document, a real-time

encapsulation format is required as, e.g., a 1500 byte packet on a

28.8 kbit/s modem link makes this link unavailable for the

transmission of real-time information for about 400 ms. This adds a

worst-case delay that causes real-time applications to operate with

round-trip delays on the order of at least a second -- unacceptable

for real-time conversation.

A true suspend/resume-oriented approach can only be implemented on a

type-1 sender [1], but provides the best possible delay performance

to this type of senders....