The IP over ATM Mailing List Archive by date

[taddy@cc.gatech.edu (Rajesh Talpade)]

> The AAL5 specification calls for AAL5 to do a CRC for each cell.
> With this being done, and the fact that lines today
> are better than when TCP was first implemented, is there
> still a need to do a checksum in TCP when running over ATM?
> 
> I was wondering if most people think not doing the checksum
> would be safe.
> 
> I could see an option to TCP where as part of
> negotiation, we negotiate whether or not to do checksums.
> This would save on one of the biggest CPU users in
> TCP/IP processing.
> 
> Any comments or reasons why this should not be done?
> 

One reason that springs to mind is what happens when the
TCP connection traverses non-ATM networks which do not 
have such error-checking. It not be always possible for a
TCP application to pre-determine the exact route that 
its connection would take to the desired destination;
ie. determine apriori whether the route is all-ATM or not.


Rajesh.
taddy@cc.gatech.edu