Load Balancer Configuration
Via: SIP / 2.0 / UDP 1.2.3.4:5060; wlsscid = 1ae4479ac6ff71; branch = z9hG4bKc5e4c3b4c22be517133ab749 adeece4e
From: sut < sip: subscribe @ 1.2.3.4:5060 >; tag = 82722c03 Max-Forwards: 70
No. Time Source Destination Protocol Info 3 7.431367 2.3.4.5 1.2.3.4 SIP Status: 200 OK
Internet Protocol, Src: 2.3.4.5( 2.3.4.5), Dst: 1.2.3.4( 1.2.3.4) User Datagram Protocol, Src Port: 9999( 9999), Dst Port: sip( 5060) Session Initiation Protocol Status-Line: SIP / 2.0 200 OK Message Header
Via: SIP / 2.0 / UDP 1.2.3.4:5060; wlsscid = 1ae4479ac6ff71; branch = z9hG4bKc5e4c3b4c22be517133ab749 adeece4e
From: sut < sip: subscribe @ 1.2.3.4:5060 >; tag = 82722c03 To: sipp < sip: sipp @ 2.3.4.5 >; tag = 1; tag = 1 Call-ID: 1-25923 @ 2.3.4.5 CSeq: 1 NOTIFY Contact: < sip: 2.3.4.5:9999; transport = UDP >
WARNING: If NAT is performed on both the source( SNAT) and destination IP addresses, the configuration does not work because the load balancer usually relies on a specific destination port number value to be sent in responses to requests. That port number value is dictated by RFC 3261, and must come from the Via header, which presents a conflict with load balancer ' s NAT requirements. RFC 3261 requires that responses to SIP requests be sent to the IP address used to send the request( unless maddr is present in the Via, as described in“ maddr-Based
Configuring Network Resources 3-9