Re: question on ESPbis, Sec. 2.1

[Stephen Kent <kent@xxxxxxx>]

At 9:30 AM -0800 1/23/03, Mark Baugher wrote:
> Steve
>   http://www.ietf.org/internet-drafts/draft-ietf-ipsec-esp-v3-03.txt 
> uses the protocol id (ESP or AH) as part of the SA lookup as an 
> option.  I don't understand why it is needed in either the unicast 
> or the multicast cases.
>
> Mark

Mark,

Your are right, it is not necessary in either case. But, for 
backwards compatibility, and because it is a local matter for the 
receiver, we don't preclude a receiver from using the protocol type 
if it wishes.

Under what circumstances do you envision that a sender might be 
confused by the possibility that two SAs to the same destination 
might have the same SPI and be differentiated only by including the 
protocol field in the lookup? A sender does not uses these values in 
its lookup of an SAD entry, so I didn't see how this would cause a 
problem.

Steve