On 08/11/2012 12:05, Ted Lemon wrote:
On Nov 8, 2012, at 6:41 AM, Brian E Carpenter
<[email protected]> wrote:
Fine, but when such an end customer buys a second router and plugs
it in,
will she get an error message that says "Please find a new ISP"?
In this case I think our only option is to fall back to bridging.
Without some fundamental surgery on the IPv6 specs, I fear that is true,
so does it have to become (gulp) a feature of the homenet architecture?
I would hate that but at the moment I see no alternative. There is
another alternative, routed ULA within the homenet and NPTv6 at the
border, but we've already said we don't want to recommend that.
I think the following paragraph of the architecture document needs
to be revised accordingly:
The home network needs to be adaptable to such ISP policies, and thus
make no assumptions about the stability of the prefix received from
an ISP, or the length of the prefix that may be offered. However, if
only a /64 is offered by the ISP, the homenet may be severely
constrained (with IPv6 not reaching all devices in the home, or use
of some form of IPv6 NAT being forced), or even unable to function.
While it may be possible to operate a DHCPv6-only network with
prefixes longer than /64, doing so would break SLAAC, and is thus not
recommended.
Something like:
The home network needs to be adaptable to such ISP policies, and thus
make no assumptions about the stability of the prefix received from
an ISP, or the length of the prefix that may be offered. However, if
only a /64 is offered by the ISP, the homenet may be severely
constrained. Attempting to use subnet prefixes longer than /64
would break SLAAC, and is thus not recommended. Using ULA prefixes
internally with NPTv6 at the boundary would be possible, but is not
recommended for reasons given elsewhere. The least damaging solution
would be for the internal routers to revert to bridging mode,
even though this would destroy the benefits of subnetting.
