Capwap Mailing List: Re: Issue 156: Need more details on use of DNS for discovery

[Pat Calhoun (pacalhou) (pcalhoun]

My apologies, Pasi. I'm not sure what I was thinking when I wrote the
text.

What I should have sent was:

<text>
   DNS:  The DNS name "CAPWAP-AC-Address" MAY be resolvable to one or
      more AC addresses.  A WTP that wishes to make use of DNS SHOULD
      use the format described in [RFC2782].  The recommended format for
      a lookup would be CAPWAP-AC-Address._udp.example.com.
</text>

Does that make more sense?

PatC 

-----Original Message-----
From: Pasi.Eronen [at] nokia.com [mailto:Pasi.Eronen [at] nokia.com] 
Sent: Wednesday, July 30, 2008 12:29 PM
To: Pat Calhoun (pacalhou); capwap [at] frascone.com
Subject: RE: Issue 156: Need more details on use of DNS for discovery

Pat Calhoun wrote:
>
> Pasi's comment was:
> 
>    Section 3.3: there's a single sentence about DNS-based discovery;
>    probably slightly more details would be useful.
> 
> Well... There's not much else we can say, but I am proposing the 
> following text In hopes that it will provide more clarity to the 
> implementor.
> 
> <new text>
> 3.3.  AC Discovery
> [...]
>       DNS: The DNS name "CAPWAP-AC-Address" MAY be resolvable to one
>       or more AC addresses.  A WTP that wishes to make use of DNS 
>       SHOULD use the format described in [RFC2782].  The recommended 
>       format for a lookup would be _capwap._udp.example.com.
> </new text>

I have some trouble parsing the 'The DNS name "CAPWAP-AC-Address" MAY be
resolvable...' part. It seems to be suggesting doing a DNS query for DNS
name "CAPWAP-AC-Address" -- or in other words, defining a new Top-Level
Domain. That probably isn't a good idea.

The two latter sentences are also leaving awfully lot of details to the
implementor -- RFC2782 has specific requirements about the labels etc.
(E.g. RFC 3861 has much more text about using SRV records for another
purpose.)

Best regards,
Pasi