RE: Common Encapsulation: CRC at beginning of frame?

["Douglas Otis" <dotis@sanlight.net>]

Robert,

In understanding the difference between these two approaches, iFCP could use
the header CRC as framing confirmation together with the timestamp in a more
resilient manner than FCIP.  iFCP also includes the Fibre-Channel frame
designators within the header for easier processing.

Doug

> I assume you are speaking of the FCIP/iFCP common encapsulation.  The
> data CRC is actually at the end of the encapsulation frame.
> The header CRC (proposed for use by iFCP only) is at the end of the
> header.  The FCIP usage of the header exploits the combination of
> TCP/IP protection, data frame verification, and data redundancy
> to achieve error detection at a comparable level and does not use
> the header CRC, simplifying the hardware and/or software
> implementations significantly.
>
> Hope that is some help.
>
> Bob
>
> -----Original Message-----
> From: Harmon, Robert [mailto:rharmon@entradanet.com]
> Sent: Wednesday, June 13, 2001 2:20 PM
> To: Ips (E-mail)
> Subject: Common Encapsulation: CRC at beginning of frame?
>
>
>
>
> Has there been any discussion of putting the
> common encapsulation CRC at the end of the frame
> rather than -near- the beginning?
> Its possible to do CRC in H/W but to put it at the
> beginning of the frame is 5 times harder than putting
> it at the end.
>