> -----Original Message-----
> From: James Undery [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, February 15, 2001 4:07 AM
> To: Arunachalam Venkataman
> Cc: [EMAIL PROTECTED]
> Subject: Re: [Sip-implementors] DNS Query required for
> re-transmission?
>
>
>
>
> Arunachalam Venkataman wrote:
>
> > Is it required to do a DNS lookup each time a
> re-transmission of a SIP
> > request (or INVITE final response) is done?
> > Or can the results of the first attempt to send be cached
> and used to
> > identify the next destination to contact?
>
> This is a matter for you, however, if you don't ensure you
> use the same A
> record for same transaction you will break the simple load
> balancing on a
> number of proxies including your own (IIRC ;^) ).
Actually, draft-ietf-sip-srv spec does discuss this:
>Clients MUSTNOT cache query results except according to the rules in
> RFC 1035 [5].
The rules here, of course, allow the resolver to cache DNS query results.
The point is that DNS caching in SIP is just standard DNS caching.
-Jonathan R.
---
Jonathan D. Rosenberg 72 Eagle Rock Ave.
Chief Scientist First Floor
dynamicsoft East Hanover, NJ 07936
[EMAIL PROTECTED] FAX: (973) 952-5050
http://www.cs.columbia.edu/~jdrosen PHONE: (973) 952-5000
http://www.dynamicsoft.com
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