Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!rutgers!ucsd!ucbvax!emdeng.UUCP!mmeier
From: mmeier@emdeng.UUCP ("Marlin.Meier")
Newsgroups: comp.protocols.ibm
Subject: Token-ring FCS question
Message-ID: <8809222144.AA19616@jade.berkeley.edu>
Date: 22 Sep 88 12:58:04 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Reply-To: "Marlin.Meier"
              
Organization: The Internet
Lines: 24

Could someone please explain what this means:

The frame check sequence is generated using the following standard
generator polynomial:
G(X) = X^32 + X^26 + X^23 + X^22 + X^16 + X^12 + X^11 + X^10 + X^8
+ X^7 + X^5 + X^4 + X^2 + X^1 + X^0.

The frame check sequence is one's complement of the sum (modulo 2) of
the following:

     1.  The remainder of X**k(X^31 + X^30 + ... + X^2 + X + 1)
         divided (modulo 2) by G(X), where k is the number of bits
         in the frame control field, destination and source addresses,
         optional routing information field, and information field.

     2.  The remainder after multiplication by X^32 and then division
         (modulo 2) by G(X) of the content (treated as a polynomial)
         of the frame control field, destination and source addresses,
         optional routing information field, and information field.

Any explaination especially with an example would be greatly appreciated.
Thanks in advance.

Marlin Meier