Sandeep,

We know that the hash addresses will duplicate. It is not possible for every 64 SAS address value to be uniquely identified in a 23 bit value. It's a question of probabilities.

So given that the SAS addresses have to follow a certain structure to be valid there is a very low probability that two SAS addresses in the same system will hash to the same value and, even if that did happen, that a frame between those two would get misdirected.

By the way your example cannot happen with a valid SAS address.
 
Bye for now,
George Penokie

Dept 9A8 030-3 A410
E-Mail:    gop@us.ibm.com
Internal:  553-5208
External: 507-253-5208



Sandeep taneja <sandeep.taneja@nsysinc.com>
Sent by: owner-t10@t10.org

10/09/2006 11:53 AM

To
t10@t10.org
cc
Monika <monika.Talwar@nsysinc.com>
Subject
Hash address Generation





* From the T10 Reflector (t10@t10.org), posted by:
* Sandeep taneja <sandeep.taneja@nsysinc.com>
*
Hi all

I have a little doubt regarding the Hash Address generation Logic

Ques:  The following two 64 bit address maps to same 24 bit address

64 bit address value   23 bit hash adress
00000000_00000001h      DB2777h
FFFFFFFF_FFFFFFFFh      DB2777h

Then How Hash address is used to check that whether frame is routed
properly or not , as from this we can assume that Hash Generation Logic
is not One to One (64 bit address maps to unique 24 bit hash address
value).


Plz suggest.........

regards
Sandeep


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