option 212 for 6RD

Jeroen Massar jeroen at massar.ch
Tue Jan 15 13:00:08 CET 2013

On 2013-01-15 12:55, Mark Townsley wrote:
> Implementing the MSS clamp only in the BR won't help for CE to CE
> connections within the 6rd domain.

Do you assume that everybody in that domain is filtering ICMP?
The tunnels are all the same MTU, thus in that case you should not have
any issues (unless someone introduces different MTU due to another
tunnel or so... but hey then your local-LAN MTU trick also fails).

As the only two reasons I've seen upto now for doing this magic are:

 - broken content providers (or other IP nodes) that filter ICMP
 - avoiding a minimal PTB hit because one is aware that the local
   network is <1500 and content providers are typically >=1500.


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