Re: frame formats

[julian_satran@il.ibm.com]

Sure - the "deep processing" required was to look at a bit.
And no we went  over the lengths. There is no need for a parity check for a
one byte field.
The Header digest plus an ocasional timeout will take care of checks.

Julo

sandeepj@research.bell-labs.com (Sandeep Joshi) on 01/04/2001 21:19:37

Please respond to sandeepj@research.bell-labs.com (Sandeep Joshi)

To:   ips@ece.cmu.edu
cc:
Subject:  Re: frame formats




To steal & reintroduce that idea, is it possible to borrow
a bit or two from the DataLen field to parity-check the AHSLen ?

Adding an entire BHS header digest, when all you need to verify
is that AHS-length field, seemed overkill.   On the other hand,
Format-1's chief disadvantage was that it required some processing
(QL) to locate either/both the length fields.   This has complicated
the choice between all these 3 formats resulting in the current vote.

Borrowing the bits for AHS parity from DataLen solves this problem.

DataLen will now be max 8M/4M but then we dont wish to have large
iSCSI PDUs in any case.  Btw, I assume Next DataLen AHS does not
exist in the new setup ?

-Sandeep

> Well, perhaps I was just not quick enough.  I thought I would let this
> settle out a bit before I added my two cents.
>
> If you all remember, some folks on this reflector gave Julian a hard time
> because you would have to use a length field that you were not sure was
OK,
> if you had a digest error and wanted to jump forward to the next, etc.
etc.
> etc.  I am sure you all remember this.  OK, now that Julian proposed a
> parity way to ensure that you could trust the length field, some of the
> parties, have now, I think, voted for format #2.  Unless you want now to
> reconsider your vote, we should stop giving Julian a hard time about the
> length not being ensured correct in the presents of a Digest Error.
>
> Either drop the session, or use the length to see if you can get
somewhere,
> search for the next marker etc.  All the stuff you said you did not like
> before.  OK, now you have format 2, but lets not go over that old ground
> now that you have decided against the parity.
>
>
> John L. Hufferd
> Senior Technical Staff Member (STSM)
> IBM/SSG San Jose Ca
> (408) 256-0403, Tie: 276-0403,  eFax: (408) 904-4688
> Internet address: hufferd@us.ibm.com
>
>
> Julian Satran/Haifa/IBM@IBMIL@ece.cmu.edu on 03/30/2001 08:51:50 AM
>
> Sent by:  owner-ips@ece.cmu.edu
>
>
> To:   ips@ece.cmu.edu
> cc:
> Subject:  frame formats
>
>
>
>
>
> Dear colleagues,
>
> It look like Format-2 is selected by popular vote.
>
> Julo
>
>
>