[DNA] DNA Hosts BCP

[Sathya Narayanan <sathya@research.panasonic.com>]

In the interest of initiating a discussion on the hosts BCP, I have 
tried to summarize the hosts BCP draft upto Section 6 below.

Reference: 
http://www.ietf.org/internet-drafts/draft-narayanan-dna-hosts-bcp-00.txt

The two steps for DNA recommended by the draft are:

1) Validation of current configuration (to identify link change)
       Example configurations are: the current IPv6 prefix and address, 
default router information and neighbour cache entries.
        Issues:
                 Use of link local addresses and subset of prefixes in 
RA messages
        Suggested solutions:
                 Confirmation of existing configuration based on 
received RA with current prefix and/or current router address.
                  CPL - Complete Prefix list
                  Confirmation of Neighbor cache entry for a global 
address (SHOULD). Use confirmation - DO NOT initiate this for validation 
test.
        Recommendations
                  We have most of them as SHOULDs. May be that is too 
conservative. Please look at section 5.3 in the draft

2) Reachability detection
       Partial reachability confirmation with the current default router 
is REQUIRED, while bi-directional is RECOMMENDED for wireless environments.
       Issues:
                Dependence on long timeouts
       Suggested solutions:
                 Neighbor discovery test (NS-NA message exchange)
                 Router discovery test (RS-RA message exchange)
                 Hybrid - both NS and RS parallely ???
                 Require authorization of the router.
       Recommendations:
                 Again, please comment on the SHOULDs and MAYs. Section 6.3

Please post comments.

-Sathya