Configuration recommendations

Recommended strategy for initial configuration

Network Appliance recommends that you configure streaming media service as follows:

Configure associated network devices for the streaming media ports required for MMS or RTSP service
Bring up the NetCache appliance on the network
Configure streaming media on the appliance
Test and troubleshoot your streaming media configuration
Configure your streaming media object management settings

Use transparency to direct requests to NetCache

The recommended way to deploy NetCache with streaming media service is to use an L4 or L7 switch or a Cisco router running WCCP 2.0 and configure transparency on the streaming media cache and on the switch or router.

See the transparency chapter in the Administration Guide and the Deployment Planning Guide for more information about transparent proxying.

Note
If you plan to implement IP spoofing with transparency, plan your deployment carefully. IP spoofing deployments are complex, requiring a variety of planning and configuration tasks. Before you deploy IP spoofing, see the transparency chapter in the Administration Guide.

Enable HTTP service

Network Appliance recommends that you enable HTTP so that clients can fail over to HTTP transport for streaming media when other ports are blocked. If HTTP is disabled, your NetCache appliance will not listen for any Web traffic, including HTTP-encapsulated streaming media requests.

Recommended duplex settings

Network Appliance recommends that you configure all clients, caches, servers, and switches for full duplex to ensure proper data delivery. Streaming content across a network configured for half-duplex data delivery is not advisable.

Determining your duplex settings

To determine the duplex settings on the streaming media cache, enter the ifconfig -a command. The following example shows sample output of the ifconfig -a command:

e0: flags=848043<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 

inet 172.30.200.53 netmask 0xffffff00 broadcast 172.30.200.255 
ether 00:a0:98:00:4e:52 (auto-100tx-up)

In the preceding example, auto-100tx-up indicates that the streaming media cache's NIC is configured for auto-negotiated 100Base-T half duplex. If your switch's NIC setting shows "auto FD" (full duplex), you should change the streaming media cache settings to match the settings of your switch.

Changing the interface duplex settings

You can change the configuration of the streaming media cache's network interfaces using the Appliance Manager or the CLI. See the network interfaces chapter in the Administration Guide for interface configuration procedures.

Limit connections to reduce client request volume

If you are concerned that your client request volume might overload the NetCache appliance or the origin server, you can change the value specified in the MMS Maximum Client Connections option and the RealSystem Maximum Client Connection option. These options limit the number of MMS and RealSystem client connections that the NetCache appliance will service. The default setting for these options is 0 (zero), which means that NetCache will accept unlimited client connections.

Note
RealSystem and Windows Media multicast clients are included in maximum client connection totals.

Do not block streaming media ports on your firewall

Blocking UDP or TCP streaming ports can seriously degrade the quality of your streaming media. When streaming ports are blocked, media players (unless configured differently) attempt to contact the streaming server using less-efficient protocols.

Configure clients to use UDP

To achieve optimal playback, streaming media must be delivered on time and at a constant bit rate. Unlike HTTP clients and servers that wait long periods to deliver and receive data, streaming clients and servers begin thinning or switching streams as soon as they encounter any type of network congestion. To speed data delivery and improve your users' playback experience, configure your streaming clients to use UDP for data transport.

Verify your UDP Port Range settings

In NetCache 5.1, the default port range for the UDP Port Range option was changed from 4000 to 65000 to 6970 to 65000. When you upgrade to NetCache 5.1 or later, the UDP port range is automatically changed to reflect the new defaults.

Note
Some servers deny access to clients that use low numbered UDP ports.

Ensure that clients are configured for Windows Media metafile rewriting

For Windows Media metafile rewriting to work, users must request streaming media content from within their browsers. The reason for this is that the Windows Media metafile rewriting process uses a nontransparent Web cache to intercept client HTTP requests for streaming media. Therefore, Windows Media metafile rewriting will not work if users access streaming media content directly from the media player (and not through a browser). The streaming request is never redirected to the streaming media cache because no initial HTTP request is sent to the Web cache.

See Implementing nontransparent redirection for MMS streaming for more information.

ACL rule creation tips for RTSP content

Because RealPlayers append the port number to streaming URLs, your ACL rules will fail unless you include the port number in the URL string. For example, consider the following ACL rule:

deny url-prefix rtsp://foo.bar.org/

The RealPlayer will add a port number to any content at the preceding URL. For example, the URL rtsp://foo.bar.org/baf.rm will become rtsp://foo.bar.org:554/baf.rm.

Therefore, your ACL rule will not match and will fail.