Streaming Media Supplement sa2150 and sa2250

Chapter 8 Configuring Media-IXT for WMT

Configuring transparent proxy caching for WMT

To perform transparent proxy caching, Media-IXT must have Adaptive Redirection Module (ARM) enabled.

If you enable ARM, you are also prompted to choose any protocols besides HTTP for which you want Media-

IXT to provide transparency. If ARM is enabled at all, Media-IXT provides HTTP transparency. Choose MMS

if you want Media-IXT to perform transparent proxy caching for WMT content, regardless of whether you use

MMS transparency and HTTP transparency or only the latter.

When you enable MMS transparency, Media-IXT edits the ipnat.conf file in the config directory, adding

a line of the form:

rdr hme0 0.0.0.0/0 port 1755 -> 10.1.1.10 port 1755 tcp

See the HP Cache Server Appliance Administrator Guide for information about ARM.

Windows Media Player retransmission requests and transparency

Because of a characteristic of the MMS protocol, a WMT player sends UDP retransmit requests as UDP packets

to port 1755.

To ensure redirection and interception of UDP packets by the ARM, this rule is defined in ipnat.conf when

transparency and WMT support are both chosen during installation:

rdr eth0 0.0.0.0/0 port 1755 -> 11.11.11.11 port 1755 udp

where 0.0.0.0/0 is the transparency network interface, and 11.11.11.11 is Media-IXT’s IP address.

A similar rule for TCP is also defined:

rdr eth0 0.0.0.0/0 port 1755 -> 11.11.11.11 port 1755 tcp

Whatever transparency device is being used must be configured so that the UDP packets reach ARM in the first

place. See the documentation for your transparency device (that is, your layer 4 switch or WCCP2 router).

Configuring a layer 4 switch for transparency

Layer 4 switches from Alteon, Arrowpoint, and Foundry are among those qualified to provide transparency for

Media-IXT. Contact your switch vendor for documentation about how to operate the switch.

The MMS protocol uses UDP for retransmission requests. This means that:

• when you configure a layer 4 switch for MMS transparency, you must configure the switch to redirect UDP

for port 1755.

• for any switch (layer 4 or not) used in a deployment of multiple Media-IXT hosts, load balancing should be

set to affinity. This way, TCP and UDP packets go to the same Media-IXT host.

For more information about these issues, and sample layer 4 switch configurations providing transparency for

streaming media protocols (RTSP and MMS) as well as HTTP, see the HP Technical Support website:

http://www.hp.com/serverappliances/support

Configuring a WCCP2-compatible router for transparency

WCCP2-compatible routers provide transparency for Media-IXT. Contact your router vendor for

documentation about how to operate the router.

NOTE Elsewhere in this manual, we say to restart Media-IXT after editing configuration

variables. That rule is valid for configuration variables associated with streaming

protocols. HTTP is not normally a streaming protocol, though, and after editing HTTP

configuration variables, the command traffic_line -x

is sufficient.