RFC 3408 (rfc3408) - Page 1 of 7
Zero-byte Support for Bidirectional Reliable Mode (R-mode) in Extended Link-Layer Assisted RObust Header Compression (ROHC) Profile
Alternative Format: Original Text Document
Network Working Group Z. Liu
Request for Comments: 3408 K. Le
Category: Standards Track Nokia
December 2002
Zero-byte Support for Bidirectional Reliable Mode (R-mode)
in Extended Link-Layer Assisted RObust Header Compression
(ROHC) Profile
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 (2002). All Rights Reserved.
Abstract
This document defines an additional mode of the link-layer assisted
RObust Header Compression (ROHC) profile, also known as the zero-byte
profile, beyond the two defined in RFC 3242. Zero-byte header
compression exists in order to prevent the single-octet ROHC header
from pushing a packet voice stream into the next higher fixed packet
size for the radio. It is usable in certain widely deployed older
air interfaces. This document adds the zero-byte operation for ROHC
Bidirectional Reliable mode (R-mode) to the ones specified for
Unidirectional (U-mode) and Bidirectional Optimistic (O-mode) modes
of header compression in RFC 3242.
1. Introduction
[RFC 3242] defines a zero-byte solution for compression of IP/UDP/RTP
packets only for Unidirectional (U-) and Bidirectional Optimistic
(O-) modes [RFC 3095]. The present specification extends the profile
defined in [RFC 3242] to provide zero-byte support for Bidirectional
Reliable (R-) mode. This specification and [RFC 3242] allow a
header-free packet format to be used in all modes to replace the
majority of the 1-octet headers of ROHC RTP packets sent during
normal operation. Specifically, the compressor operating in R-mode
is allowed to deliver a No-Header Packet (NHP) when [RFC 3242] would
have required it to deliver a ROHC Reliable Packet Type Zero (R-0)
packet [RFC 3095].
Liu & Le Standards Track