MTU handling in 6RD deployments

Mikael Abrahamsson swmike at
Fri Jan 17 17:14:44 CET 2014

On Fri, 17 Jan 2014, Templin, Fred L wrote:

> Sorry, I was looking at the wrong section. I see now that Section 8 is 
> talking about a method for a CE to send an ordinary data packet that 
> loops back via the BR. That method is fine, but it is no more immune to 
> someone abusing the mechanism than would be sending a ping (or some 
> other NUD message). By using a ping, the BR can impose rate-limiting on 
> its ping responses whereas with a looped-back data packet the BR really 
> can't do rate limiting.

You don't ping the BR, you ping yourself via the BR. The BR only forwards 
the packet.

> Also, Section 8 of RFC5969 only talks about the CE testing the forward
> path to the BR. Unless the BR also tests the reverse path to the CE it
> has no way of knowing whether the CE can accept large packets.

You misread the text.

Mikael Abrahamsson    email: swmike at

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