Re: [Sip] Question on rfc3263 - locating sip servers

[Amit Bhadoria <bhadoria@cisco.com>]

udi,

its not a MUST to do a DNS querry for subsequent messages, you could cache
the results from last successfull querry and use it. however, in case of
failover, or to handle some non-trivial case, you may have to do DNS
querry again -- and thats exactly what these guidelines are for, to give a
standard/open procedure.

as a side note, the Record-route inserted by each intermediate hop gives a
little hint on how it wants to be resolved for subsequent messages. for
example, it may choose to insert its domain only, in which case you may
have to do NAPTR/SRV querries.

regards,
-amit.
--
Amit Bhadoria
Software Engineer
http://www.cisco.com

On Thu, 5 Jun 2003, Udi Weintrob wrote:

> Hi,
> I have a question regarding RFC3263.
> 
> from the RFC (4):
> Because the ACK request for 2xx responses to INVITE constitutes a
> different transaction, there is no requirement that it be delivered
> to the same server that received the original request (indeed, if
> that server did not record-route, it will not get the ACK).
> 
> Does that mean that for ACK on 2xx responses, I need to re-query the DNS
> server (assuming a non IP uri)?
> Do I need to query the DNS even if the URI of the ACK is the same as the URI
> of the initial INVITE request?
> 
> thanks,
> Udi J. Tirosh.
> 
> _______________________________________________
> Sip mailing list  https://www1.ietf.org/mailman/listinfo/sip
> This list is for NEW development of the core SIP Protocol
> Use sip-implementors@cs.columbia.edu for questions on current sip
> Use sipping@ietf.org for new developments on the application of sip
> 

_______________________________________________
Sip mailing list  https://www1.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol
Use sip-implementors@cs.columbia.edu for questions on current sip
Use sipping@ietf.org for new developments on the application of sip