End systems in end user networks that connect to the IPv6 Internet will likely want to configure IPv6 VPNs, e.g., so that they can securely connect to their home office networks. Those VPN links must present a 1280 minimum MTU to upper layers, but if they traverse a link in the path with a too-small MTU then the end system will see an MTU underrun and will need to use IPv6 fragmentation.
An IPv6-in-IPv4 tunnel with a fixed static 1280 MTU is an example of a link in the path that could cause such an MTU underrun for end system VPN links. So, should we be concerned that tunnels with a fixed 1280 MTU would make life difficult for the common operational practice of end systems using VPNs? Thanks - Fred [email protected] > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of > Templin, Fred L > Sent: Friday, October 08, 2010 7:52 AM > To: Yiu L. Lee; Brian E Carpenter; Ole Troan > Cc: Softwires; [email protected] > Subject: Re: [v4tov6transition] [Softwires] ISP support of > NativeIPv6across NAT44 CPEs -Proposed 6a44 Specification > > > > CPE. This double tunneling tech seems scary. > > 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? > > Fred > [email protected] > _______________________________________________ > v4tov6transition mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/v4tov6transition > _______________________________________________ Softwires mailing list [email protected] https://www.ietf.org/mailman/listinfo/softwires
