nanog mailing list archives
Re: Internet Exchanges supporting jumbo frames?
From: Martin Pels <m.pels () tech leaseweb com>
Date: Thu, 10 Mar 2016 15:15:55 +0100
On Thu, 10 Mar 2016 08:23:30 +0200 Tassos Chatzithomaoglou <achatz () forthnet gr> wrote:
Niels Bakker wrote on 10/3/16 02:44:* nanog () nanog org (Kurt Kraut via NANOG) [Thu 10 Mar 2016, 00:59 CET]:I'm pretty confident there is no need for a specific MTU consensus and not all IXP participants are obligated to raise their interface MTU if the IXP starts allowing jumbo frames.You're wrong here. The IXP switch platform cannot send ICMP Packet Too Big messages. That's why everybody must agree on one MTU.Isn't that the case for IXP's current/default MTU? If an IXP currently uses 1500, what effect will it have to its customers if it's increased to 9200 but not announced to them?
None. Until someone actually tries to make use of the higher MTU. Then things start breaking. Let's say I'm a customer at this IXP. I have 100 peers. I have one peer that likes large MTUs, so I set my L3 MTU to 9000 (or whatever I agree with this peer). Now I have broken connectivity towards my 99 other peers who are all still at 1500. So today you need a separate VLAN for Jumbo's, which some IXPs have. On this VLAN you will only find the peers that actually care about Jumboframes. The majority of IXP participants don't bother to connect to this VLAN for varying reasons. If the number of interested parties is too low, IXPs may well decide it is not worth the investment of time and resources to set this up, implement monitoring for it, deal with customers messing up their configs, etc. In order for Jumboframes to be successful on IXPs _on a large scale_ the technology has to change. There needs to be a mechanism to negotiate MTU for each L2 neighbor individually. Something like draft-van-beijnum-multi-mtu-03, which was mentioned before in this thread. With this in place individual sets of peers could safely use different MTUs on the same VLAN, and IXPs would have a migration path towards supporting larger framesizes. -- Kind regards, Martin Pels Network Engineer LeaseWeb Technologies B.V. T: +31 20 316 0232 M: E: m.pels () tech leaseweb com W: http://www.leaseweb.com Luttenbergweg 8, 1101 EC Amsterdam, Netherlands
Current thread:
- Re: Internet Exchanges supporting jumbo frames?, (continued)
- Re: Internet Exchanges supporting jumbo frames? Mark Andrews (Mar 12)
- Re: Internet Exchanges supporting jumbo frames? Mark Tinka (Mar 09)
- Re: Internet Exchanges supporting jumbo frames? Tassos Chatzithomaoglou (Mar 09)
- Re: Internet Exchanges supporting jumbo frames? Kurt Kraut via NANOG (Mar 09)
- Re: Internet Exchanges supporting jumbo frames? Niels Bakker (Mar 09)
- Re: Internet Exchanges supporting jumbo frames? Tassos Chatzithomaoglou (Mar 09)
- Re: Internet Exchanges supporting jumbo frames? Frank Habicht (Mar 12)
- Re: Internet Exchanges supporting jumbo frames? Chris Woodfield (Mar 17)
- Re: Internet Exchanges supporting jumbo frames? Nikolay Shopik (Mar 17)
- Re: Internet Exchanges supporting jumbo frames? Baldur Norddahl (Mar 17)
- Re: Internet Exchanges supporting jumbo frames? Kurt Kraut via NANOG (Mar 09)
- Re: Internet Exchanges supporting jumbo frames? Martin Pels (Mar 12)
- Re: Internet Exchanges supporting jumbo frames? Tassos Chatzithomaoglou (Mar 10)
- Re: Internet Exchanges supporting jumbo frames? Saku Ytti (Mar 10)
- Re: Internet Exchanges supporting jumbo frames? Mikael Abrahamsson (Mar 10)
- Re: Internet Exchanges supporting jumbo frames? Mikael Abrahamsson (Mar 10)
- Re: Internet Exchanges supporting jumbo frames? Nick Hilliard (Mar 10)
- Re: Internet Exchanges supporting jumbo frames? Tassos Chatzithomaoglou (Mar 10)
- Re: Internet Exchanges supporting jumbo frames? Mikael Abrahamsson (Mar 10)
- Re: Internet Exchanges supporting jumbo frames? Dale W. Carder (Mar 18)