Configuring the WSM using Device Manager

How RTSP server load balancing works

The objective of RTSP server load balancing is to intelligently switch an RTSP request, and other media streams associated with a presentation, to a suitable RTSP server using the configured load-balancing metric. The WSM supports one Layer 7 metric (URL hashing and URL pattern matching) and all Layer 4 load-balancing metrics. To configure Layer 7 URL pattern matching, see Configuring RTSP SLB using pattern matching.

RTSP load balancing with the URL hash metric can be used to load balance cache servers that cache multimedia presentations. Since multimedia presentations consume a large amount of Internet bandwidth, and their correct presentation depends upon the real time delivery of the data over the Internet, several caching servers cache the multimedia data. As a result, the data is available quickly from the cache, when required. The Layer 7 metric of URL hashing directs all requests with the same URL to the same cache server, ensuring that no data is duplicated across the cache servers.

Typically, RTSP clients establish a control connection to RTSP servers over TCP port 554 and issue RTSP commands to it. On receiving the first command, the WSM chooses an RTSP server, using the configured Layer 4 metric. The WSM then routes the request by splicing a connection to the server.

Note: RTSP load balancing is not applicable if the streaming media (multimedia) servers use HTTP protocol to tunnel RTSP traffic. To ensure RTSP server load balancing works, make sure the streaming media server is configured for RTSP protocol.

RTSP clients issue sequences of commands to establish connections for each component stream of a presentation. The procedure varies, depending upon the RTSP client and server.