Path: utzoo!attcan!uunet!ncrlnk!emdeng!mmeier
From: mmeier@emdeng.Dayton.NCR.COM (Marlin.Meier)
Newsgroups: comp.protocols.ibm
Subject: Token-ring FCS question
Keywords: Token-ring, token ring
Message-ID: <549@emdeng.Dayton.NCR.COM>
Date: 22 Sep 88 12:58:04 GMT
Organization: E&M Dayton, NCR Corporation, Dayton, Ohio
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