On 26 May 2014 19:24, James Harper <[email protected]> wrote: >> >> On 26 May 2014 18:07, Russell Coker <[email protected]> wrote: >> > On Mon, 26 May 2014 17:47:06 Toby Corkindale wrote: >> >> I don't understand why you're worried about enabling the jumbo frames >> >> though. It doesn't break backwards compatibility. Your 100baseT stuff >> >> will continue to function fine. >> > >> > Except that a switch will drop a jumbo packet destined for a non-jumbo >> port. >> > So you can have situations where things work at low speed but break as >> soon as >> > you send lots of data and get a larger TCP segment size. >> >> I've never seen that in practice, and I've been running gigabit >> networks for a while. >> Rather than totally dropping the packet if the destination port >> doesn't support it, the switch should alert the sender that they must >> fragment their packets. Path MTU discovery. Although actually I think >> some (most?) switches instead just do the fragmentation themselves. > > This almost certainly isn't possible unless it's an L3 managed switch, and > even then I've never heard of such a thing. IP is Layer 3 while Ethernet is > Layer 2, which is all most switches do.
Ah OK. I stand corrected. There's definitely some mechanism that lets a jumbo-frame client talk to a non-jumbo-frame client via a switch though. I swear I do this and it Just Works(tm). Perhaps MSS at the IP layer then? _______________________________________________ luv-main mailing list [email protected] http://lists.luv.asn.au/listinfo/luv-main
