Hi Daniel, The INVITE contains maddr=10.150.152.102 and hope server can do multicasting to several phones to achieve paging functionality: INVITE sip:9621@10.150.152.102:5060;transport=udp;maddr=10.150.152.102 SIP/2.0^M Via: SIP/2.0/UDP 10.150.151.38:5060;branch=z9hG4bK042e71c1c3819bf6b^M Max-Forwards: 70^M From: Phone_1 <sip:19725509623@10.150.152.102>;tag=fdd5d85838;epid=SC27fd6e^M To: <sip:9621@10.150.152.102:5060;transport=udp>;tag=SEC11-a96960a-1e9b960a- 1-0174t58y1o62^M Call-ID: 466658c69bd278b0^M CSeq: 2 INVITE^M Contact: Phone_1 <sip:19725509623@10.150.151.38:5060;transport=udp>^M Min-SE: 90^M Supported: timer, replaces, 100rel^M User-Agent: optiPoint 420 Advance/V7 V7 R5.3.0^M X-Control4-Call-Type: ST-insecure^M Content-Type: application/sdp^M Regards, Ming From: Daniel-Constantin Mierla [mailto:miconda@gmail.com] Sent: Friday, March 25, 2011 12:57 AM To: SIP Router - Kamailio (OpenSER) and SIP Express Router (SER) - Users Mailing List Cc: Ming Liu Subject: Re: [SR-Users] any one use multicast for paging ? Hello, On 3/24/11 3:21 PM, Ming Liu wrote: Hi, Need help on paging case. The via header has maddr field contains multicast ip address, how does this configure ? can you paste here such INVITE? I am not really understanding from your message what exactly you are looking for, maybe you can give a bit more details about what you expect to happen. Cheers, Daniel And how does sip proxy server react ? Advice would be appreciated. Ming _______________________________________________ SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list sr-users(a)lists.sip-router.org http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users -- Daniel-Constantin Mierla http://www.asipto.com