Re: I-D Action:draft-wbeebee-v6ops-ipv6-cpe-router-bis-00.txt

[Brian E Carpenter <brian.e.carpenter@gmail.com>]

> 4.3.  6to4 Automated Tunneling (MEDIUM)/Dual-Stack Lite (DEV)/ISATAP
>       (MEDIUM)
> 
>    If the IPv4 address assigned to the WAN interface of the CPE Router
>    is a non-[RFC1918] IPv4 address, and the CPE Router fails to acquire
>    an IPv6 address before WAN_IP_ACQUIRE_TIMEOUT seconds after acquiring
>    the IPv4 address, then the 6to4 tunneling protocol [RFC3056] SHOULD
>    be enabled automatically, allowing tunneling of IPv6 packets over
>    IPv4 without requiring user configuration.  If an anycast 6to4 server
>    cannot be located, the CPE Router MAY initiate ISATAP [RFC4214] to
>    establish IPv6 connectivity over the IPv4 network.  

This is slightly wrong IMHO. Firstly we should be clear that the CPE is
to behave like a 6to4 router as defined in 3056. Secondly, 3056 does not
define the anycast method; in fact it assumes that a unicast address is
configured for the nearest 6to4 relay (*not* "server").  So, let me
rephrase this:

                ...  then 6to4 router behavior [RFC3056] SHOULD
   be enabled automatically, allowing tunneling of IPv6 packets over
   IPv4 without requiring user configuration. Note that [RFC3056] relies
   on configuration of an IPv4 address for a 6to4 relay router. The CPE
   SHOULD allow this, but also SHOULD by default use the anycast method
   defined in [RFC3068]. If a 6to4 relay router cannot be contacted,
   the CPE router MAY initiate ISATAP ...


     Brian