RFC 3759 (rfc3759) - Page 2 of 20

RObust Header Compression (ROHC): Terminology and Channel Mapping Examples

RFC 3759     ROHC Terminology and Channel Mapping Examples    April 2004


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  2
   2.  Terminology. . . . . . . . . . . . . . . . . . . . . . . . . .  3
   3.  ROHC External Terminology. . . . . . . . . . . . . . . . . . .  6
       3.1.  Network Elements and IP Interfaces . . . . . . . . . . .  6
       3.2.  Channels . . . . . . . . . . . . . . . . . . . . . . . .  7
       3.3.  A Unidirectional Point-to-Point Link Example . . . . . .  8
       3.4.  A Bi-directional Point-to-Point Link Example . . . . . .  8
       3.5.  A Bi-directional Multipoint Link Example . . . . . . . .  9
       3.6.  A Multi-Channel Point-to-Point Link Example. . . . . . .  9
   4.  ROHC Instances . . . . . . . . . . . . . . . . . . . . . . . . 10
       4.1.  ROHC Compressors . . . . . . . . . . . . . . . . . . . . 11
       4.2.  ROHC Decompressors . . . . . . . . . . . . . . . . . . . 12
   5.  ROHC Channels. . . . . . . . . . . . . . . . . . . . . . . . . 13
   6.  ROHC Feedback Channels . . . . . . . . . . . . . . . . . . . . 14
       6.1.  Single-Channel Dedicated ROHC FB Channel Example . . . . 14
       6.2.  Piggybacked/Interspersed ROHC FB Channel Example . . . . 15
       6.3.  Dual-Channel Dedicated ROHC FB Channel Example . . . . . 16
   7.  ROHC Contexts. . . . . . . . . . . . . . . . . . . . . . . . . 17
   8.  Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
   9.  Implementation Implications. . . . . . . . . . . . . . . . . . 18
   10. Security Considerations. . . . . . . . . . . . . . . . . . . . 19
   11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 19
   12. Informative References . . . . . . . . . . . . . . . . . . . . 19
   13. Author's Address . . . . . . . . . . . . . . . . . . . . . . . 19
   14. Full Copyright Statement . . . . . . . . . . . . . . . . . . . 20

1.  Introduction

   In RFC 3095, the RObust Header Compression (ROHC) standard framework
   is defined, along with 4 compression profiles [RFC-3095].  Various
   concepts are introduced within the standard that are not all very
   extensively defined and described, which can easily be an obstacle
   when trying to understand the standard.  This can especially be the
   case when one considers how the various parts of ROHC relate to the
   surrounding environments where header compression may be used.

   The purpose of this document is to clarify these aspects of ROHC
   through examples and additional terminology, discussing terms such as
   ROHC instances, ROHC channels, ROHC feedback, and ROHC contexts.
   This especially means to clarify how these terms relate to other
   terms, such as network elements and IP interfaces, which are commonly
   used for example when addressing MIB issues.  One explicit goal of
   this document is to support and simplify the ROHC MIB development
   work.





Jonsson                      Informational