On Sat, 9 Jan 2010, Mark Smith wrote:
Why can't a CPE router send unicast RAs to other CPE routers as long as they are not malicious and do not in any way conflict with the RAs sent by SP routers?I think on some networks that could have multicast traffic volume related scaling issues. It's quite possible to build single Ethernet link layers using DSL that have 100s or 1000s of CPE attached. It also seems a bit redundant to have the CPEs fully aware of all their neighbours' downstream prefixes, yet be unlikely to use those routes very often.
I think no ISP will ever build a network that allows for local routing like that (at least not intentionally). So far ISPs do not want customers to talk L2 directly with each other, but instead want to do the routing between customers (mostly for security reasons). I therefore think it's a moot point to try to drive any standard that by a lot of security measures tries to solve this in the CPE. It just won't be deployed because of its complexity.
-- Mikael Abrahamsson email: swmike@swm.pp.se