Oracle WebLogic Communication Services Configuration

4-16 Oracle WebLogic Communications Server Administration Guide Example 4–4 Oracle WebLogic Communication Services Routing Table sbinroute Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 10.1.0.0 255.255.0.0 U 0 0 0 eth0 default 10.1.3.4 0.0.0.0 UG 0 0

4.9.3 Load Balancer Configuration

The load balancer is configured with a virtual IP address of 1.2.3.4, and two real servers, WLSS 1 and WLSS 2, having addresses 10.1.1.1 and 10.1.1.2, respectively. The load balancer also has an internal IP address of 10.1.3.4 configured on the 10.116 network. The UAC address, 2.3.4.5, is reachable from the load balancer by static route configuration on the load balancer. The load balancer routing table is shown in Example 4–5 . Example 4–5 Load balancer Routing Table sbinroute Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 10.1.0.0 255.255.0.0 U 0 0 0 eth1 1.2.0.0 255.255.0.0 U 0 0 Because the SIP protocol specification RFC 3261 dictates the destination IP address and UDP port numbers that user agents must use when sending requests or responses, the NAT configuration of the load balancer must be done in a way that does not violate RFC 3261 requirements. Three setup options can be used to accomplish this configuration: ■ Section 4.9.3.1, NAT-based configuration ■ Section 4.9.3.2, maddr-Based Configuration ■ Section 4.9.3.3, rport-Based Configuration The sections that follow describe each approach.

4.9.3.1 NAT-based configuration

The default UDP NAT behavior for load balancers is to perform destination IP address translation in the public private network direction, and source IP address translation in the private public network direction. This means setting up destination address translation in the UAC Oracle WebLogic Communication Services 2.3.4.5 1.2.3.4 direction without source address translation, and source address translation in the Oracle WebLogic Communication Services UAC 10.116 2.3.4.5 direction without destination address translation. Figure 4–6 illustrates the UDP packet flow for a SUBSCRIBE200OK transaction. Managing Network Resources 4-17 Figure 4–6 SUBSCRIBE Sequence Note that the source and destination IP addresses of the UDP packets are shown in blue. In the UAC Oracle WebLogic Communication Services direction, the load balancer translates the destination IP address but not the source IP address. In the Oracle WebLogic Communication Services UAC direction, the load balancer translates the source IP address but not the destination IP address. The complete message trace including IP and UDP headers, as well as the SIP payload for the sequence from Figure 4–6 is shown in Example 4–6 below. Example 4–6 Complete SUBSCRIBE Message Trace No. Time Source Destination Protocol Info 1 1.425250 2.3.4.5 1.2.3.4 SIP Request: SUBSCRIBE sip:subscribe1.2.3.4:5060 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 Request-Line: SUBSCRIBE sip:subscribe1.2.3.4:5060 SIP2.0 Message Header Via: SIP2.0UDP 2.3.4.5:9999;branch=1 From: sipp sip:sipp2.3.4.5;tag=1 To: sut sip:subscribe1.2.3.4:5060 Call-ID: 1-259232.3.4.5 Cseq: 1 SUBSCRIBE Contact: sip:sipp2.3.4.5:9999 Max-Forwards: 70 Event: ua-profile Expires: 10 Content-Length: 0 No. Time Source Destination Protocol Info 2 2.426250 2.3.4.5 10.1.1.1 SIP Request: SUBSCRIBE sip:subscribe1.2.3.4:5060 Internet Protocol, Src: 2.3.4.5 2.3.4.5, Dst: 10.1.1.1 10.1.1.1 User Datagram Protocol, Src Port: 9999 9999, Dst Port: sip 5060 Session Initiation Protocol Request-Line: SUBSCRIBE sip:subscribe1.2.3.4:5060 SIP2.0 Message Header Via: SIP2.0UDP 2.3.4.5:9999;branch=1 From: sipp sip:sipp2.3.4.5;tag=1 To: sut sip:subscribe1.2.3.4:5060