Several IPv6 routers and default gateway choice

[Victor Sudakov]

Hiroki Sato wrote:
> va> Can any IPv6 unicast or link-local address be configured as an anycast
> va> address of a router?
> 
>  Yes.  There is no restriction about address scope.
> 
>  You might want to read RFC 4291, which defines Subnet-Router anycast
>  address, and RFC 2526, which defines the other reserved IPv6 subnet
>  anycast addresses.  In general, the former one can be used for
>  routing purpose.

Interestingly, RFC4291 says that "All routers are required to support
the Subnet-Router anycast addresses for the subnets to which they have
interfaces." In practice, I don't observe this. A FreeBSD router does
not configure such an address automatically, for example.

RFC2526 is dim, I think it's because of this RFC the last usable address
on a subnet ends in ff7f instead of ffff. I wonder if anyone anywhere
uses those subnet anycast addresses.


-- 
Victor Sudakov,  VAS4-RIPE, VAS47-RIPN
2:5005/49 at fidonet http://vas.tomsk.ru/
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