[188179] in North American Network Operators' Group
Re: Internet Exchanges supporting jumbo frames?
daemon@ATHENA.MIT.EDU (Mikael Abrahamsson)
Thu Mar 10 12:16:52 2016
X-Original-To: nanog@nanog.org
Date: Thu, 10 Mar 2016 18:16:46 +0100 (CET)
From: Mikael Abrahamsson <swmike@swm.pp.se>
To: Tassos Chatzithomaoglou <achatz@forthnet.gr>
In-Reply-To: <56E1A73E.9090804@forthnet.gr>
Cc: nanog@nanog.org
Errors-To: nanog-bounces@nanog.org
On Thu, 10 Mar 2016, Tassos Chatzithomaoglou wrote:
> Mikael Abrahamsson wrote on 10/3/16 18:21:
>>
>> However, I stand by my earlier statement that we need to include MTU/MRU in ND messages, so that this can be negotiated on a LAN where not all devices support large MTU.
>>
>
> Isn't this already supported?
> https://tools.ietf.org/html/rfc4861#section-4.6.4
That is in RAs, and pertains to a prefix. Also, if a device can't use the
advertised MTU, they will keep lower MTU which might be causing MTU
mismatch.
For instance, if I announce 9000 as MTU and a device is bridged via wifi,
wifi chips generally only supports around 2300 in MTU, so you'll have MTU
mismatch with MTU blackholing within the same L2 network. This is bad.
--
Mikael Abrahamsson email: swmike@swm.pp.se
