> Perry, I think its not that simple.
> 
> The multicast tunnelling code uses IP in IP nowadays, too (source routing for
> this purpose is deprecated, AFAIK), so there is already an entry for the
> IP in IP in the protocol switch table (at least if you have options MROUTING).

This isn't the same thing.  IP multicast uses IP protocol 4 encapsulation
(i.e. IPPROTO_IPIP), as does IP mobility.  RFC 1241 is IP protocol 98
encapsulation (i.e. IPPROTO_ENCAP).  You can do whatever you want to the
second without touching the first.

Dennis Ferguson