Baniel Uri-CUB001 wrote:
>
> So I guess my question is either just too dumb or too boring :(
> Still, is there any good soul on the list, who has a moment to go over the
> question and respond.
Uri:
I'll take a a shot at it (I have also moved this to the SIP Implementors
list)...
> Say a UAC gets the following SIP URL from its user in the 'To' and
> 'request URI' fields: "[EMAIL PROTECTED]". How does the UAC 'guess' if
> 'ieee.org' refer to a specific host or a domain? Looks like according
> Bis02 para 1.4.2, the UAC tries to get DNS SRV record first, and then A
> record if the former query has failed. Is that true? If yes, looks like
> according the DNS RFC, one may issue a DNS query w/ multiple types (e.g.
> _sip, a, aaaa) and act based on the response. Was that the intention of
> Bis?
That's my understanding. First extract the host portion from the R-URI and
if it is not an IP address, prepend _sip._udp.ieee.org. If the query
succeeds, you've got your SIP server. If not, try _sip._tcp.ieee.org
(assuming the UAC supports TCP). If SRV query fails, try prepending "sip"
to the host (sip.ieee.org). If all else fails, try A and AAAA RRs. If even
that fails, then curse and give up (the cursing part is optional, though
very therapeutic :-)).
- vijay
--
Vijay K. Gurbani vkg@{lucent.com,research.bell-labs.com,acm.org}
Internet Software and eServices Group
Lucent Technologies/Bell Labs Innovations 263 Shuman Blvd., Rm 1A-413
Naperville, Illinois 60566 Voice: +1 630 224 0216 Fax: +1 630 713 0184
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