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