Re: New (-02) version of IPv6 CPE Router draft is available for review

[Antonio Querubin <tony@lava.net>]

On Mon, 21 Jul 2008, Ralph Droms wrote:

> This discussion brings up the problem of subscriber network operation - is it 
> an explicit goal of this document that the subscriber network be able to 
> operate even if the WAN interface is not up?  What are the expectations for 
> that unconnected operation and what services must the CPE router provide to 
> meet those expectations?

I suspect I'm over-simplifying but this comes down to whether the 'dentist 
office' operation needs to continue operations.  I think it does.  Should 
the CPE router even send RAs or any hint of it's presence until the WAN 
connection is confirmed to be working?  On one hand, a CPE router with a 
single logical LAN interface can be designed to provide virtual presence 
of the SP connection iff connectivity through the WAN is available.  And 
that can be predicated on whether the CPE router is able to obtain or 
sense some kind of connectivity from the SP.  Once that single LAN/WAN 
behaviour is pinned down, then what remains to be determined is how 
multiple LAN interfaces in a CPE router should interact if the WAN or 
upstream connectivity is down.

> According to the spec, the requesting router can only use the delegated 
> prefix until the lease on the prefix expires.  We hadn't thought about 
> relaxing that restriction to allow the requesting router to continue to use 
> the delegated prefix until it has a WAN connection back to the delegating 
> router.

Difficult to predict how this will play out but if the design goal of this 
draft is a hands-off CPE router, it's hard to see how connectivity between 
multiple LANs in the subscriber's network can be maintained reliably 
without some kind of forced persistence behaviour.

Antonio Querubin
whois:  AQ7-ARIN