Subject: RE: [PWE3] MPLS PID

From: "Naidu, Venkata" <[email-masked]>
Date: Thu, 27 Mar 2003 12:12:06 -0500

Shahram,

-> First of all I meant computing CRC over the first 20 byte of 
-> payload header
-> and comparing it to the suspected IP CRC in octets 11 and 12 
-> of the payload.
-> If they match then it is IPv4, if not it is something else 
-> (similar procedure for IPv6)
-> 
-> Secondly I am proposing it now. Is there a problem? 

  Yes. There is a problem. First of all relaying on CRC to
  figure out the *type* of payload is not at all advisable.
  One could produce (there is a remote possibility) a payload
  which is not IPv4 or IPv6 but the CRC can be matched to
  the payload of first 20 bytes to the bytes in 11 & 12.

  RFC1071 uses 16 bit's one's compliment, which we all know
  that won't catch all the bit errors/flips.

Venkata.