MTU handling in 6RD deployments

Anfinsen, Ragnar Ragnar.Anfinsen at
Thu Jan 9 20:18:14 CET 2014

On 09.01.14 16:56, "Templin, Fred L" <Fred.L.Templin at> wrote:

>Hi Ragnar,

Hi Fred.

>What is the MTU as seen by the IPv6 hosts - 1480? Something less?

Yes. Since we set the MMS to 1420, which is 20 bytes lower than the
default 1440. By doing this we only see 1480 sizes packets for IPv6.

>Would it not be better if they could see 1500+?

Yes, but then we would need to upgrade all our access routers, which then
again would give us the possibility to do native Dual Stack.


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