> -----Original Message----- > From: Rémi Després [mailto:[email protected]] > Sent: Monday, October 11, 2010 9:29 AM > To: Washam Fan; Templin, Fred L > Cc: Softwires; [email protected] > Subject: Re: [v4tov6transition] IPv6 VPNs configured over > 1280 MTU tunnels > > Hi Washam and Fred, > > Le 9 oct. 2010 à 05:02, Washam Fan a écrit : > > ... > > For this bullet in sec5, draft-despres-softwire-6a44-00 > > > > o 6a44 Server functions refuse packets received from their IPv6 > > pseudo interfaces if their sizes exceed 1280 octets, > with ICMPv6 > > Packet Too Big messages returned to sources as required by > > [RFC2460].) > > > > I think it could only apply to the case where the received IPv6 > > packets forwarded to the external domain. In the case the > 6a44 server > > does the hairpinning, the 6a44 server would refuse packets > whose size > > exceed (IPv4 MTU - 28) octets, with ptb ICMPv6 msg. > > ... > > > >>> -----Original Message----- > >>> From: [email protected] > >>> [mailto:[email protected]] On Behalf Of > >>> Templin, Fred L > >>> ... > >>> More to this point about double-tunneling, how were > >>> folks thinking that IPv6 VPNs would be run over a > >>> 1280 MTU IPv6-in-IPv4 tunnel? That is double-tunneling, > >>> and seems like it would be a quite common case, but the > >>> MTU seems deficient. Should it use IPv6 fragmentation? > >>> ... > > Actually, the 6a44 specification should, instead of 1280, > require IPv4 MTU - 28 octets, both for hairpinning and > traversal cases.
How can you be sure that IPv4 PMTUD will work in the traversal case? Fred > (It is only hosts that should better take 1280 as default MTU > if not having reliable PMTU discovery.) > I will check with co-authors to fix it in a later version. > > Thanks to both of you for the discussion. > RD > > > _______________________________________________ Softwires mailing list [email protected] https://www.ietf.org/mailman/listinfo/softwires
