Hi all, Now I am developing a software using pjsip, and I have such problem.As a callee, I always received two INVITE package when the caller call from the mobile or landline. the different points between the tow package are the rdata->pkt_info.timestamp have about 3~5 sec interval. and Call-ID: 4117-4a3-623201034714-img-03-mas-0-125.213.168.12 Call-ID: 41f4-49d-623201034711-img-03-mas-0-125.213.168.12 Via: SIP/2.0/UDP 125.213.160.81:5060;branch=z9hG4bK17dd5a0514c4910c2-8a3b9-0 Via: SIP/2.0/UDP 125.213.160.81:5060;branch=z9hG4bK17dd5a0514c4910bf-5c10d-0 CSeq: 566201 INVITE CSeq: 377101 INVITE and in the package o=- 145908437 145908437 IN IP4 125.213.160.81 o=- 487389775 487389775 IN IP4 125.213.160.81 c=IN IP4 125.213.160.79 c=IN IP4 125.213.160.80 m=audio 19758 RTP/AVP 18 2 98 8 0 116 4 101 m=audio 19538 RTP/AVP 18 2 98 8 0 116 4 101 The situation do not come up when the caller start from a networking telephone. The trace describe that the method of "endpt_on_rx_msg" in the sip_endpoint.c receive two packages like above. I have no idea why this problem happens, Can someone tell me why? Thanks Best Regards Steven