On Wed, 2 Jul 2008, Shin Miyakawa wrote:
Mikael,It's standard industry practice to use loopback addresses for almost everything control plane in routers, as then the IGP will handle reroutes and established TCP sessions are not affected by interfaces going up or down.In CPE router case, it is not true, isn't it ? Because in today's environment a CPE has only one IPv4 address which is assigned to the WAN interface of the CPE.
Well, I think in the IPv6 case that CPEs need to be more advanced than todays devices. I foresee 3G/4G backups for the WAN port for instance.
Also, the reason for only assigning single global IPv4 space to customers is usually because of scarcity of IPv4 addresses, and the ISPs I know of who allow for multiple addresses, do this via kludges (local-proxy-arp for instance, which means that local traffic between customer computers risk going over the WAN).
Also, I would have liked to do the core/customer IP block thing for IPv4 as well, it's just that the support for that in cheap customer CPEs just isn't there.
-- Mikael Abrahamsson email: swmike@swm.pp.se