On 3/8/19 8:38 AM, Saku Ytti wrote:
Hey,now for UDP, I don't know yet how does things like QUIC can be handled ...Unfortunately the magic answer you were hoping does not exist, what they do is they just send smaller packets.
What we almost seem to be moving toward in this discussion is an IP header where the path can reduce the reported MTU which can then be read at the receiving end. This would be somewhat like ECN just with more than a couple bits.
Of course, we know how well extension headers, much less hop-by-hop headers, are handled on IPv6...
Re-writing a field in the L4 header works, but it seems ugly since it means every hop that reduces the MTU of the link has to know every L4 that participates in such a scheme.
ICMP is nice in that it's totally protocol agnostic and doesn't require altering of packets in transit. It's a shame we can't reasonably rely on it being delivered.
-- Brandon Martin
