Subject: [homenet] Prevent configuration of unneeded prefixes

From: Teco Boot <[email-masked]>
Date: Tue, 15 Nov 2011 07:01:34 +0100

The BRDP proposal I made for Autoconf (ad hoc networks) has some concepts that applies to Homenet also. For example, configuration of unneeded prefixes should be prevented. BRDP does so by checking already RA advertised prefixes with advertised ISP prefix blocks:
http://tools.ietf.org/html/draft-boot-brdp-framework-00
>    Having multiple prefixes from the same ISP bound on a link
>    is not useful.  So a router requests a prefix from a Border Router
>    only if no other prefix of that Border Router is advertised already
>    by another router on this network segment.
This requires awareness of ISP provided prefix blocks. It is needed by source address based forwarding also. So run BRDP or develop something similar.  

A related issue is a requirement, or not, on complete set of on-link prefixes in RAs.
RFC 4861 says:
>    A router SHOULD include all its on-link prefixes ...
What to do? Shall all routers on a link repeat the prefix? Or only the initiator or election winner and let hosts accumulate the whole set?

Teco