nanog mailing list archives
Re: exchange point media
From: Simon Leinen <simon () limmat switch ch>
Date: 21 Jul 2000 20:30:16 +0200
"ma" == Mikael Abrahamsson <swmike () swm pp se> writes:I was under the impression that there is nothing magical about jumbo frames and that there are no interoperational problems with them as long as they're supported at all. Please correct me if I am wrong.
I'm afraid you are wrong... all interfaces connected to a logical IP subnetwork should have the same MTU. For most Layers-2 there is a pretty well-established default such as 1500 for Ethernet, 4470 for FDDI (well for ATM many people use 4470 rather than the IETF suggestion of 9180). But for Gigabit Ethernet the only standard MTU is the Ethernet MTU (1500). For a new exchange point built on Gigabit Ethernet, it could be worthwhile to postulate a larger MTU such as 8192 or 9180 and make sure every participant actually uses exactly that. But most exchange points supporting GigE still provide bridging to legacy (Fast) Ethernet, on which larger MTUs are uncommon or not supported at all. And bridging between Layer-2s is similarly problematic to having different MTUs in a LIS, although I'm well aware that such configurations are being used in many places, and thanks to bridges that do clever stuff besides bridging this may even work more or less reliably. -- Simon.
Current thread:
- exchange point media Mikael Abrahamsson (Jul 17)
- <Possible follow-ups>
- Re: exchange point media Richard A. Steenbergen (Jul 17)
- Re: exchange point media Mikael Abrahamsson (Jul 17)
- Re: exchange point media Simon Leinen (Jul 21)
- Radius Opinions Bradly Walters (Jul 21)
- Re: Radius Opinions Don Cary Grant (Jul 21)
- Re: Radius Opinions Greg A. Woods (Jul 21)
- Re: Radius Opinions Steve Sobol (Jul 21)
- Radius Survey Results Bradly Walters (Jul 22)
- Re: Radius Survey Results Jim Mercer (Jul 22)
- Re: exchange point media Mikael Abrahamsson (Jul 17)