Internet Exchanges supporting jumbo frames?
Mikael Abrahamsson
swmike at swm.pp.se
Wed Mar 9 15:58:51 UTC 2016
On Wed, 9 Mar 2016, Nick Hilliard wrote:
> used. Some will want 9000, some 9200, others 4470 and some people
I have a strong opinion for jumboframes=9180bytes (IPv4/IPv6 MTU), partly
because there are two standards referencing this size (RFC 1209 and 1626),
and also because all major core router vendors support this size now that
Juniper has decided (after some pushing) to start supporting it in more
recent software on all their major platforms (before that they had too low
L2 MTU to be able to support 9180 L3 MTU).
In order to deploy this to end systems, I however thing we're going to
need something like
https://tools.ietf.org/html/draft-van-beijnum-multi-mtu-04 to make this
work on mixed-MTU LANs. The whole thing about PMTUD blackhole detection is
also going to be needed, so hosts try lower PMTU in case larger packets
are dropped because of L2 misconfiguration in networks.
With IPv6 we have the chance to make PMTUD work properly and also have
PMTU blackhole detection implemented in all hosts. IPv4 is lost cause in
my opinion (although it's strange how many hosts that seem to get away
with 1492 (or is it 1496) MTU because they're using PPPoE).
--
Mikael Abrahamsson email: swmike at swm.pp.se
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