Christian The Gatekeeper in my opinion cannot resolve absence of destination alias to any valid address. You will always receive a ARJ. The first ARQ you sent should have had the incomplete dest alias and not NULL. You follow the ARJ with additional ARQs as and when you keep getting additional information about the destination and when finally the gatekeeper can translate this address, it will send you a ACF with either its own Call sigannling address (Gk routed) or any other. For eg. Lets assume Ep1 is a terminal connected to a LAN and supports H.323 with overlapped sending. The User wants to dial 91-80-5598615. As and when the user dials each digit (or a set of digits) it sends out a ARQs to its Gatekeeper with destination alias set to say 9 (first ARQ) , 91 (second ARQ) , and so on. Lets assume that the Ep1's gatekeeper has an entry that maps 91-80 (prefix) to a Gateway's call signalling address, the Gatekeeper sends an ACF for the ARQ that contains "91-80" as the destination alias. The ACf can contain the Gatekeeper's Call Signalling address (if the Gatekeeper routes the call) or the Gateway's Call signalling address, and then the Setup, setup acknowlegde, information message sequence takes over. Hence the setup goes only after the ACF is received and only one ACF is received by Ep1 and not two as you have indicated Hope this helps Regards Sudharshan -----Original Message----- From: Christian Geng <christian.geng@detewe.de> To: ITU-SG16@mailbag.cps.intel.com <ITU-SG16@mailbag.cps.intel.com> Date: Tuesday, August 10, 1999 1:29 PM Subject: overlapped Sending in h.323

Dear Sir or Madam,

I try to be H.323 conform in the folowing: I want to support overlap sending within gatekeeper-routed calls. My session starts with a ARQ from enpoint_1 to GK without any destination alias. After receaving ACF endpoint_1 sends SETUP without any destination alias, but with canQverlapSend is TRUE. GK will answer with a SETUP ACKNOWLEDGE. Endpoint_1 will then send digit by digit of alias in destinationInfo field of ARQs. By each sending the total cumulative addressing information is transmitted in destinationInfo field. GK responds each time with an ARJ until recept full destination alias, in this case it answers with ACF. I hope I am right until now? Reading clause 8.1.12 of ITUs H.323 I thought endpoint_1 shall then send a SETUP message to GK? This will be the second SETUP, because enpoint_1 allready did. Can't GK send now a SETUP to endpoint_2 with the ip-address belonging to the destination alias put in the destCallSignalAddress field?

I thank you much for an answer to solv my problem.

Cincerely

Christian Geng