[ixp1200] hash unit

[Michael E. Kounavis]

Hi Damien,

The hash algorithm is the following:

The user sepcifies the coefficients 
of an input polynomial A(x) (48 or 64 bits).

The polynomial is multiplied by a standard 
multiplier M(x) and then divided by a 
Generator polynimial G(x). The coefficients
of the reminder R(x) form the returned hash
index. 

The algorithm is described in the "Hash Algorithm"
Section of the Hardware Reference Manual in the
documentation.  

The generator polynimials used by IXP1200 for the 
48 and 64 bit hash operations are listed there 
as well. 

Hope this helps

Mike

--
Michael E. Kounavis
http://comet.columbia.edu/~mk
 


-----Original Message-----
From: owner-ixp1200 at CS.Princeton.EDU
[mailto:owner-ixp1200 at CS.Princeton.EDU] On Behalf Of Damien
Sent: Thursday, September 05, 2002 5:39 PM
To: ixp1200 at CS.Princeton.EDU
Subject: [ixp1200] hash unit


Does anyone know exactly what function the hash unit implements?  I'm 
getting weird results for my test hashes and I want to double check it 
against what I'm supposed to get.

--Damien