RE: Posted a new copy of CPE Rtr draft

["Wes Beebee (wbeebee)" <wbeebee@cisco.com>]

> Unfortunately, I don't think it's possible to manually configure an
alternative for subdelegation, 
> assuming the (sub)delegation isn't a fixed prefix.

If you knew how many bits were in the prefix, you could say:
SP prefix : my bits : identifier

Where my bits came from a table of bits and output interfaces.  An
automatic configuration algorithm would simply assign the "my bits" in
the table (perhaps sequentially or randomly).  To manually config, all
you need to do is edit the table of bits.

As long as the SP prefix length didn't change, the table of bits could
remain fixed through a SP renumbering.

To make this practical, you'd need to assume that the table wasn't that
large.  This would work well for a home, but may not be appropriate in
an enterprise scenario.

> I don't think that's necessary. We could make it such that a CPE
detects whether other CPEs or non-CPE devices
> are connected to its LAN ports. Then, if only one LAN port is active
and that LAN port connects to a device
> identifying as a CPE, the first CPE disables its WLAN interfaces, if
any, and transparently bridges between its
> WAN and LAN ports. The only question in this scenario is how
management of the original CPE would happen in the
> unnumbered scenario. But if that's a problem people can always use the
numbered scenario...

Imagine a scenario where the SP manages a router embedded in a cable
modem, and the home user has a router behind that.  Both may want to
administer their own routers at the trust boundary.  Imagine the
surprise from the service provider if they find that their router
suddenly became a bridge!  The user would be surprised if their box
suddenly became a bridge automatically too.

It seems to me that being a bridge or a router is a fundamental change
in the network topology and should not be done "automatically".

> Iljitsch