Would be thanxful if I can get an answer to the following question.
In IPV6, only the source node fragments the packet, and the assembly
happens at the destination. The fragment size is determined by a
finding out the MTU on the path - implying that the source now knows
the route that the packet has to take to reach the destination. My
doubt is this: Will a datagram in UDP have to traverse a path that is
discovered before it is sent out (since the source may have to fragment
the packet)or will it work just like in IPV4 where its route is
determined by routers between the source & destination?
In essence, will datagrams exhibit the same behaviour as in the
previous version of IP?
IPv6 UDP works just like IPv4 UDP with DF bit set.
- first (or a couple of) packets can get dropped due to PMTUD,
if you throw packet larger than minimum path MTU.
- if you would like to avoid PMTUD, you can try sending packet
fragmented into minimum link MTU (1280). there's an API defined for
this (see draft-ietf-ipngwg-2292bis-02, section 11.1 and 11.2)
itojun