Guidelines for using multiple proxy servers

In enterprise deployments with a high level of Internet traffic, install multiple proxy servers with an IBM® Sametime® Gateway cluster. Then, front these proxy servers with an IP sprayer to ensure load balancing and high availability. Configure the IP sprayer to balance incoming Connections between the proxy servers.

About multiple XMPP proxy servers

This release does not support multiple XMPP proxy server configurations. Although an XMPP proxy server is installed with every SIP proxy server, you should configure only one XMPP proxy server in the cell.

About multiple SIP proxy servers

Follow these guidelines for setting up multiple SIP proxy servers to work with an IP sprayer and a Sametime Gateway cluster:

  1. Install each SIP proxy server's node on its own host.
  2. Federate and configure each additional proxy server as a node.

Setting up traffic forwarding with the IP sprayer

The IP sprayer is typically a hardware-based load balancer. Ask your network administrator for help setting it up and configuring it.

When communicating with a public external community, the Sametime Gateway SIP proxy servers inspect the IP source address of incoming IP packets. Each incoming packet's source address is compared to a list of IP addresses known to be associated with the external public community. To ensure that a connection can be completed, the original source IP address must be retained as it passes through the IP sprayer (pass-through mode). The IP sprayer should not be configured to replace the source address of the incoming IP packets with its own (IP sprayer) address.

The TCP/IP connection between the proxy servers and an external Internet server can remain open for long periods of time. Be sure that there are no TCIP/IP inactivity timeout intervals configured for TCP-aware devices that the connection is tunneled through.

Monitoring proxy server availability

Set up the IP sprayer to check the availability of each proxy server every 2 seconds (by making sure that the TCP/IP 5060 and 5061 ports are available). If a proxy server is unavailable, the IP sprayer should be configured to suspend spraying new TCP Connections until the proxy server becomes available again.