Subject: Header Stripping

From: Ali Irfan-FIA225 <[email-masked]>
Date: Thu, 7 Oct 1999 17:44:09 -0500

Question:
1.	Should a recommendation for header stripping/regeneration be allowed
in any IP network?
2.	Also, should this issue be dealt with in the performance
implications draft?

Background:

I was just reading a Cellular network proposal (the name of group or doc. is
not important) for an IP network. For air-link optimization,
header-compression is recommend. Fine. In addition an option for
header-striping and regeneration down-stream is also allowed.  A statement
in the doc. states, 

	"Reducing of the header size is done by removing redundancy in the
originally coded header information AND/OR REMOVING HEADER FIELD INFORMATION
AND THERBY LOSING FUNCTIONALITY"

This disturbed me. I want to make a contribution to the group to delete such
text, but would first like  to get some feedback from this mailing list.

Note: the doc. does state that these options are to be investigated and a
final recommendation made. So header-stripping option is not set in stone,
yet.

Irfan Ali
Motorola

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From: Omar Elloumi <[email-masked]>
Date: Fri, 08 Oct 1999 10:45:00 +0200

I'm new in this list but I would like to contribute with two points:
- In 4.2: The underutilisation of link (10 s timeout) is not well explained.
I'm not sure that this high value is only due to the variation of the RTT.
It can also be due to the TCP exponential back-off which doubles
the RTO whenever a retransmitted packet is lost. Could the authors
include a reference to the study reporting this under-utilisation!

- For some cases the network can be symmetric from a TCP point
of view (k<=1)* but due to MAC algorithms such as the one used in
802.14, acks can be subject to ack compression:  acks are delayed
while waiting for grants and then sent back to back in burst.
This is reported in the following paper:
ftp://ftp.rennes.enst-bretagne.fr/pub/reseau/elloumi/

--
____________________________________________________________
Omar Elloumi

Alcatel Research - Network Architecture - Traffic Technology

Francis Wellesplein 1, 2018 Antwerp, Belgium

Phone: + 32 3 240 78 33
Fax:   + 32 3 240 99 32
http://www.alcatel.com/crc/
____________________________________________________________

Opinions expressed are those of the sender and do not reflect Alcatel policy or
agreement

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From: Omar Elloumi <[email-masked]>
Date: Fri, 08 Oct 1999 11:05:14 +0200

> ftp://ftp.rennes.enst-bretagne.fr/pub/reseau/elloumi/

Sorry the link is in fact
ftp://ftp.rennes.enst-bretagne.fr/pub/reseau/elloumi/tcp_hfc.ps

Phone: + 32 3 240 78 33
Fax:   + 32 3 240 99 32