Basic sip questions belong on the sip-implementors list. shiori_maeda wrote:
> Dear all, > > Sorry for immature questions. I am studying the SIP. I read the rfc > document and books, I, however, could not understand the basic. In > particular, I don't understand the routing. > Could you let me know the following? > If this mailing-list is not proper, please ignore this, or let me > know the appropriate one. > > I would like to confirm the behaviors of UA and Proxy. Could you > point out the mistake in my understanding? > ------ > 1) The case of exchanging the messages directly between UAs > This is the standard of sip message flow, I think. It assume that > UAs know the global address to each other. They would need to know each others IP address or host name, yes. This is definitely not a common case anywhere but the lab. > a) request > Request is sent to the address which is indicated in Request-URI, not > To header. In all cases, To header is NOT used as routing > destination. Right. > b) response > Response is sent to the address which is indicated in Via header, not >>From header. In all cases, From header is NOT used as routing > destination. Right, with the caveat that the response is sent to the PORT in the via, but at the source address of the request. > > 2) The case of exchanging the message via proxy, not registrar. > a) request > Using DNS look-up, request is sent to the domain server(=sip proxy) > which is the indicated in domain name of Request-URI. SIP proxy > looks up the callee address from its storage(e.g. database), adds the > own address to Via header, and then forwards request to that address. Yes. > b) response > Response is sent to the address which is indicated in the topmost Via > header. Proxy deletes the topmost Via header(i.e. own address), then > sends it to second Via header. Right, with same caveat above. -Jonathan R. -- Jonathan D. Rosenberg, Ph.D. 72 Eagle Rock Avenue Chief Scientist First Floor dynamicsoft East Hanover, NJ 07936 [EMAIL PROTECTED] FAX: (973) 952-5050 http://www.jdrosen.net PH: (973) 952-5000 http://www.dynamicsoft.com _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
