Re: other comments on draft-nielsen-v6ops-3GPP-zeroconf-goals-00. txt

[Alain Durand <Alain.Durand@Sun.COM>]

Pekka Savola wrote:

> As to the attributes of the reverse lookup schemes, one might say a 
> few good / bad sides, like:
>   - bad side is that requires a lot of records

   not an issue as they can be generated with script.

>   - also requires some kind of special population of the private 
> address space etc. if used between the user and the customer, pretty 
> ugly.


This is an area that need invetigation, I agree.

>   - increases the number of required lookups

Not necessarily. Think CNAME and additional section.

>   - on the other side, allows more flexible, IP-specific configuration
>
> Also, two particular more generic issues, AFAIR, which could be 
> discussed a bit more might be:
>
>   - the "granularity" of the discovery process, i.e., how precisely 
> and easily should you be able to modify the results of the lookup, 
> e.g., tune that hosts A..B within a single administrative domain 
> should discover X, hosts B..C should discover Y, etc. (for example, 
> when using DNS, one way to achieve this would be split-faced DNS, or 
> looking up stuff from the reverses like Alain proposes).

In practice, I think this is an important operational issue.

>   - the manageability domain of the host.  It can be argued that IP 
> addresses are often more "local" than host names.  A search path could 
> include even all of the enterprise, all over the world, while 
> customizing the lookup results (above) based on the IP address might 
> go closer to the administrative domains.


Search path are just plain wrong. As I explained several times, 
internally at Sun, we have domains
that span the planet and many hosts are`configured with several domains 
in their search path.

> It could also be argued that this may not be all that severe a problem 
> here, if DNS is combined with anycast (provided that split DNS is not 
> used).  Even if node X gets the same IP address everywhere by looking 
> up x_srv.example.com, x_srv.example.com can be anycasted, set up 
> everywhere using the same IP address.

That makes the asumption that we know how to limit the propagation of 
anycast routes
within large domains. This is certainly doable, but the associated 
complexity is large.

   - Alain.