ISPPlanet Cache Review Series - NetApp NetCache C720

Streaming Multimedia
This NetCache release also supports Apple QuickTime, Microsoft Windows Media, and RealNetworks G2 multimedia formats. Webcasts and on-demand digital audio and video are transmitted to the NetCache; the cache acts as a transparent proxy, allowing live content to be split and shared by nearby clients. Moving multimedia distribution to the network edge drastically reduces origin server load and WAN bandwidth consumption. But, unlike other content types, multimedia is not stored on the NetCache.

We tested Microsoft MMS and industry-standard RTSP protocols by requesting audio and video streams using Windows Multimedia and RealAudio players. Due to client limitations, only RTSP can be received in forward proxy mode; both protocols can be received in transparent mode.

Thus, our first configuration task was to policy-route ports 1755 (MMS) and 554 (RTSP) to the NetCache. We used the NetCache UI to add licenses, then enabled MMS and RTSP on the Streaming Media Settings page (right). ACLs can be configured to restrict access to multimedia and client log records can be forwarded to a log server for accounting purposes.

Overall bandwidth savings appear on the Monitor home page, with historical and status detail supplied by the Streaming Video Instrumentation page (left). In a limited WAN bandwidth configuration, we used the NetCache to split simultaneous video from MSNBC to several PCs. When this test was repeated without the NetCache, competition for scarce bandwidth broke these connections. We experienced one reboot when trying to display stats. The problem was not repeatable and is suspected to be a beta bug; Network Appliance is investigating.