Subject: RE: [Tsvwg] I-D ACTION:draft-ietf-tsvwg-sctpcsum-00.txt

From: [email-masked]
Date: Sun, 5 Aug 2001 01:13:05 +0300

Hi all!

	Because of some work I'm doing now, I was looking for the standard
in which CRC-16 was specified... After some time I managed to get that ITU
standard, in which both CRC-16 and CRC-32 are defined, which is ITU-T
V.42... Then, some time later I thought that I had been quite silly since
the reference should appear in the sctpcsum draft... So, I have gone there,
but the reference is another one, V.41... Just because I'm so curious I have
gone and checked that other standard and guess what I have found... The
CRC-32 is not defined there... :-)

	It is kind of funny, since I have seen other RFCs (for example 2823)
that use CRC-32 and they also have that reference, V.41...

	Just go and check ITU-T V.41 and try to find any reference to
CRC-32... nothing... just CRC-16... Moreover, the definition of the CRC-16
algorithm is not there, just the polynomial used...

	So I guess that the right document in the References section would
be:

	[CRC-32] ITU-T Recommendation V.42, "Error-correcting procedures for
DCEs using asynchronous-to-synchronous conversion", section 8.1.1.6.2,
October 1996.

	One last minor thing. In the paragraph that makes the reference to
the ITU-T standard, you can read:

	"... in [CRC-32] and uses the polynominal polynomial is (X^32..."

	Wouldn't it be better...

	"... in [CRC-32] and the used polynomial is (X^32..."	?

	That's all folks! Thanks!

	BR Iván Arias Rodríguez

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From: Randall Stewart <[email-masked]>
Date: Sun, 05 Aug 2001 03:39:01 -0500

Ivan:

Well.. I got the reference from the same RFC you looked at :)
So an error is amplified :)

I will make both of your changes in the next pass of the document..

R

-- 
Randall R. Stewart
[email-masked] 815-342-5222 (cell phone)

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From: "Douglas Otis" <[email-masked]>
Date: Sun, 5 Aug 2001 10:38:24 -0700

Randall,

Is there a reason why the CRC-32c polynomial is not considered rather than
the ITU V.4x if there is a demonstrated orders of magnitude improved pud for
jumbo frames.  A major router company supports these size frames in their
equipment as well as most 1 GE adapter manufactures although such is outside
the IEEE specifications.  Would it not make sense to consider this
polynomial?  The ips workgroup has already selected this CRC-32c polynomial
to handle jumbo frames.  In my mind, the IETF should recommend a polynomial
of choice for new transports.  With such a large degree of improvement for
jumbo frames, it seems likely the ITU CRC would be the wrong choice where it
has only been assured with the smaller packets.

Doug

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]]On Behalf Of
> Randall Stewart
> Sent: Sunday, August 05, 2001 1:39 AM
> To: [email-masked]
> Cc: [email-masked]
> Subject: Re: [Tsvwg] I-D ACTION:draft-ietf-tsvwg-sctpcsum-00.txt
>
>
> Ivan:
>