Hi, Joe, Just one nit:
On 7/9/19 20:35, Joe Touch wrote: > FWIW, in general: > > With all the concern not detecting when frag fails, I’d like to point out > that it’s equally impossible to detect when it works, e.g., when it happens > on tunnels that start more than one hop away or more than one layer of > intermediate headers. > > E.g, PLPMTUD turns of frag *on the connected interface*. There’s no way to > disable source fragmentation that happens later in the network (as it would > at tunnel ingresses) or deeper in the stack (when what you think is your > interface is locally tunneled over a layer you don’t even know about). > > So *all* systems that try to backoff and use smaller MTUs are actually > *already* testing whether fragmentation already works in those cases. Even if > your app sends a 1-byte packet you have no idea that some set of layers > inflates the headers (e.g., with signatures or key exchanges) beyond the MTU > somewhere. This would seem to be incorrect. IP has a minimum MTU of 68 bytes, and IPv6 has a minimum MTU of 1280. Hence if you send packets smaller than or equal to the minimum MTU, the packets should go through. -- Fernando Gont SI6 Networks e-mail: [email protected] PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492 _______________________________________________ Int-area mailing list [email protected] https://www.ietf.org/mailman/listinfo/int-area
