Subject: SRV records

From: Henning Schulzrinne <[email-masked]>
Date: Mon, 28 Feb 2000 12:42:39 -0500

Now that SRV records are a Proposed Standard (RFC 2782), I would suggest
simplifying the lookup procedure to include SRV as SHOULD rather than as
an optional procedure. This does not force modifying DNS to include SRV
records, but does encourage implementation of SRV in SIP clients.

Comments?
-- 
Henning Schulzrinne   http://www.cs.columbia.edu/~hgs

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From: Jonathan Rosenberg <[email-masked]>
Date: Mon, 28 Feb 2000 16:57:23 -0500

My only concern is regarding latency. Every proxy will do an SRV query,
and in most cases, will get (and have to wait for) a negative response.
Then, it needs to do another query for A records. Negative responses can
take a long time... not sure if thats just if there is no server for
that domain, or also if there is a server for that domain, but the
requested record doesn't exist.

-Jonathan R.

-- 
Jonathan D. Rosenberg                       200 Executive Drive
Chief Scientist                             Suite 120 
dynamicsoft                                 West Orange, NJ 07052
[email-masked]                     FAX:   (732) 741-4778
http://www.cs.columbia.edu/~jdrosen         PHONE: (732) 741-7244
http://www.dynamicsoft.com

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From: Henning Schulzrinne <[email-masked]>
Date: Mon, 28 Feb 2000 16:59:25 -0500

> requested record doesn't exist.

We might have had this discussion before, but my experience is that if a
domain exists, but a record doesn't, the response is very fast (110 ms
without caching and 20 ms with caching, including the "host" application
overhead). If the domain doesn't exist, it doesn't matter one way or the
other. I just tried

host -t srv sip.udp.dynamicsoft.com
sip.udp.dynamicsoft.com does not exist (Authoritative answer)

and it returns immediately.

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From: Dean Willis <[email-masked]>
Date: Tue, 29 Feb 2000 13:40:54 -0600

I concur.

--
Dean

> -----Original Message-----
> From: [email-masked]
> [mailto:[email-masked]]On Behalf Of Henning
> Schulzrinne
> Sent: Monday, February 28, 2000 11:43 AM
> To: [email-masked]
> Subject: SRV records
> 
>