Subject: Protocol Action: ROHC over PPP to Proposed Standard

From: The IESG <[email-masked]>
Date: Tue, 29 Jan 2002 19:45:51 -0500

The IESG has approved the Internet-Draft 'ROHC over PPP'
<draft-ietf-rohc-over-ppp-04.txt> as a Proposed Standard.  This
document is the product of the Robust Header Compression Working
Group.  The IESG contact persons are Allison Mankin and Scott Bradner.

Technical Summary
 
   A number of cellular IP designs, especially in the 3GPP2 and
   GPRS arenas, will send IP traffic over a PPP link layer.  It is
   desirable to apply ROHC to the traffic carried on the PPP,
   especially to RTP datagrams where e.g. the voice payloads are already
   compressed by the voice codec.

   In order to establish compression of IP datagrams sent over a PPP
   link, each end of the link must agree on a set of configuration
   parameters for the compression. The process of negotiating link
   parameters for network layer protocols is handled in PPP by a family
   of network control protocols (NCPs).  Since there are separate NCPs
   for IPv4 and IPv6, this document defines configuration options to be
   used in both NCPs to negotiate parameters for the RFC 3095 header
   compression scheme.

   ROHC does not require that the link layer be able to indicate the
   types of datagrams carried in the link layer frames.  However, there
   are two basic types of ROHC headers defined in the ROHC framework:
   small-CID headers (zero or one bytes are used to identify the
   compression context) and large-CID headers (one or two bytes are used
   for this purpose).  To keep the PPP packets self-describing, in this
   document two new types for the PPP Data Link Layer Protocol Field are
   defined, one for small-CID ROHC packets and one for large-CID ROHC
   packets.  (This also avoids a problem that would occur if PPP were to
   negotiate which of the formats to use in each of IPCP and IPV6CP and
   the two negotiation processes were to arrive at different results.)

Working Group Summary

 The working group achieved strong consensus.  The document was also
 last called in the PPPEXT working group and there were no objections.

Protocol Quality

 The PPPEXT chair and several other PPP experts gave reviews to the
 editors.

 Allison Mankin reviewed the document for the IESG