option 212 for 6RD

Tassos Chatzithomaoglou achatz at forthnetgroup.gr
Sat Jan 19 17:07:15 CET 2013

Ivan, i have the impression that in the newest BRAS/BNG platform (ASR9k, so it's actually
IOS-XR, not IOS), the router uses automatically the IPv4 TCP MSS configured value minus 20
bytes as the IPv6 TCP MSS value.


Ivan Pepelnjak wrote on 19/1/2013 17:15:
> Oh, BTW, there's no "ipv6 tcp adjust-mss" command in Cisco IOS. Problem "solved" ;)
>> That said, if you read between the lines of the original question, it
>> suggests:  I have no control over my subscribers' CPEs . Which makes the
>> LAN MTU solution extremely impractical to deploy. In that situation, the
>> solution that is the most likely to yield the best effect, would be to
>> enable TCP MSS clamping for 6RD traffic on the BR (or somewhere else in
>> the ISP's core network). IMHO.
>> --
>> Tore Anderson

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