Configure multiple proxy servers using a load balancer in a multihomed environment

We can configure multiple proxy servers with multiple network interfaces using a load balancer in a multihomed environment.

Communications Enabled Applications (CEA) enables you to have multiple network interfaces on multiple proxy servers using a load balancer.

In a multihome environment, we need to define multiple virtual IP (VIP) alias addresses at the proxy server, and we need to define the proxy transport chains for each VIP alias address.

Avoid trouble: Do not use an asterisk (*) for the transport chain names. Instead, use host names and IP addresses for the transport chains. gotcha

The following setup includes configuring a load balancer with two clusters, and two proxy servers with two VIP alias addresses defined. Ensure that the following steps are repeated for both proxy servers.

1. In the console, expand...
   Servers | Server Types | WebSphere proxy servers | proxy_name | Proxy Settings | SIP Proxy Server Settings | SIP proxy settings

2. Under Load balancer health checking, set the Load balancer members for IP address 1 and IP address 2.

   The IP address of the load balancer is used to source the SIP health checks.

3. Under Container facing network interface, specify the UDP interface.

   The UDP interface specifies the network interface for all UDP data that goes to and from the backend SIP containers.

4. Click Custom properties and set the default protocol chain name types for each protocol type (UDP, TCP, and TLS).

   Default chain name to use on the proxy server. From the SIP proxy settings panel, custom properties can be set up to specify the appropriate default interface for each protocol. These interfaces are used to send outbound requests when an application does not specify which interface to use.

   1. In the console, expand...
      Servers | Server Types | WebSphere proxy servers | proxy_name | Proxy Settings | SIP Proxy Server Settings | SIP proxy settings | Custom properties

   2. Enter the appropriate chain name to configure the transports section of the SIP proxy settings. There is one custom property for each transport type.

   Custom Property Name	Description
   defaultUDPChainName	The default UDP chain name to use when setOutboundInterface is not called.
   defaultTCPChainName	The default TCP chain name to use when setOutboundInterface is not called.
   defaultTLSChainName	The default TLS chain name to use when setOutboundInterface is not called.

5. In the console, expand Servers > Server Types and click WebSphere proxy servers > proxy_name.

6. Under Proxy Settings, expand SIP Proxy Server Settings and click SIP proxy server transports.

7. On the Transport Chain panel:

   1. Add two TCP transport chains using the host name or IP address for each network interface.

   2. Add two UDP transport chains using the host name or IP address for each network interface.

   3. Add two UDP transport chains using the VIP alias addresses of the proxy servers so that the load balancer can communicate with the proxy servers. These two unique VIP alias addresses must be the same on both proxy servers.

8. Recycle the proxy server.

Results

You have successfully configured multihomed network interfaces for two proxy servers using a load balancer.

Related concepts

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