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

["Hemant Singh (shemant)" <shemant@cisco.com>]

Antonio and Ralph,

Even if the CPE Router WAN interface is down, one does expect LAN services between devices in the home to work.  My printer server is connected to one LAN interface while few PC's in my home are connected to another LAN interface.  Therefore IPv6 data forwarding and routing should continue to work in the home.  Only use of ULA then provides this continued operation in the home.  Also, a home router always includes a bridge internally (it has been mentioned in the mailer) that is always on if the device is powered up.  The LAN of the CPE router is connected to this bridge.  LAN can totally continue to work in the home even if WAN is down.

Hemant

-----Original Message-----
From: Antonio Querubin [mailto:tony@lava.net] 
Sent: Monday, July 21, 2008 5:29 PM
To: Ralph Droms (rdroms)
Cc: Rémi Denis-Courmont; Alain Durand; Hemant Singh (shemant); v6ops@ops.ietf.org; Wes Beebee (wbeebee)
Subject: Re: New (-02) version of IPv6 CPE Router draft is available for review

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