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@CS.Princeton.EDU [mailto:owner-ixp1200@CS.Princeton.EDU] On Behalf Of Damien Sent: Thursday, September 05, 2002 5:39 PM To: ixp1200@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