[140541] in North American Network Operators' Group
Re: Interested in input on tunnels as an IPv6 transition technology
daemon@ATHENA.MIT.EDU (Iljitsch van Beijnum)
Fri May 13 04:03:27 2011
From: Iljitsch van Beijnum <iljitsch@muada.com>
In-Reply-To: <1305265953.18376.1032.camel@karl>
Date: Fri, 13 May 2011 10:02:40 +0200
To: Karl Auer <kauer@biplane.com.au>
Cc: NANOG List <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On 13 mei 2011, at 7:52, Karl Auer wrote:
> I'm working on a talk, and would be interested to know what people =
think
> is good about tunnels as an IPv6 transition technology, and what =
people
> think is bad about tunnels.
Without tunnels we'd have no IPv6 today. Even today many people, =
especially home users, depend on them. But it would have been impossible =
to get IPv6 started by running it native-only.
Tunnels can work very well and if they're direct they can be almost as =
good as native connectivity. However, in the past we saw Europeans get =
tunneled IPv6 connectivity from Japan. That kind of thing is very bad =
because it inflates RTTs and thus slows everything down.
Enabling automatic tunneling by default is also a mistake because then =
you think you have IPv6 even if the automatic tunnel doesn't work =
because relays are unreachable or stuff is firewalled.
A downside of tunneling is the reduced MTU, but hopefully the fact that =
tunnels are common makes people fix PMTUD problems rather than blindly =
send 1500-byte packets and let the chips fall where they may that way =
too many people do with IPv4.
So... tunnels can be good or can be bad, but native is still better than =
a good tunnel.=
