On Mon, Aug 31, 2015 at 5:17 PM, Masataka Ohta <mohta@necom830.hpcl.titech.ac.jp> wrote:
for routers, generating ICMP PTB is as burdensome as generating fragments?
No, it isn't. 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. 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) before communication can succeed. There are potentially several orders of magnitude of difference in the burden on the router. Regards, Bill Herrin -- William Herrin ................ herrin@dirtside.com bill@herrin.us Owner, Dirtside Systems ......... Web: <http://www.dirtside.com/>