Re: PMTUD for IPv4 Multicast - How?

[Masataka Ohta <mohta () necom830 hpcl titech ac jp>]

William Herrin wrote:

> > for routers, generating ICMP PTB is as burdensome
> > as generating fragments?
>
> No, it isn't.

Yes, it is. Generating an ICMP PTB @aclet　is as burdensome as
fragmenting　a packet.

> When a router fragments a packet, it has to fragment the next and the
> next and the next. Maybe tens or hundreds of thousands of packets
> before the end of that one user's session.

Not necessarily, because transport layer can react against fragmented
packets.

> When a router generates a PTB, there is no next. PTB is a soft
> failure. The origin must correct the error (by reducing packet size)

What if, the origin does not reduce packet size?

                                                        Masataka Ohta