Streaming Media Supplement sa2150 and sa2250

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Chapter 8 Configuring Media-IXT for WMT
When content is not cacheable, Media-IXT goes into passthrough mode and proxies, but does not cache, the
content.
See the HP Cache Server Appliance Administrator Guide for more information about selective caching.
Two configuration files control selective caching:
• cache.config controls cacheability
• filter.config controls proxyability
You must edit cache.config and filter.config manually, adding selective caching rules to the files.
Given that WMT streaming requires both an origin Windows Media Server for the streaming content, and an
HTTP server for the WMT metafiles, you must decide whether your selective caching rules should apply to one
or both. Each requires a separate set of rules.
There are optional RNI and QT tags for selective caching rules, but no WMT tag, because there is no need for
one: the scheme specifier with a value of mms is just as good as a WMT tag. See the HP Cache Server Appliance
Administrator Guide for details how rules are applied when conflicting rules apply to the same request.
The kinds of selective caching rules you can write for WMT differ from those you can write for RealNetworks
and QuickTime. For
WMT
, always use IP addresses, not hostnames, in selective caching rules. That is, the use of
dest_domain and dest_host rules for WMT is not supported. You must use dest_ip and url_regex
instead.
After you modify the cache.config or filter.config, tell Media-IXT to re-read them. From Media-
IXT’s bin directory, run the command:
./traffic_line -x
This section provides an overview of selective caching with an emphasis on WMT-specific issues that do not
appear in the HP Cache Server Appliance Administrator Guide.
Modifying the filter.config file to determine proxyability
To add a new rule to filter.config, you need exactly one primary specifier, may add one or more
secondary specifier, and must choose one of two possible actions.
The primary specifier
The primary specifier must be one of the following:
• dest_ip, meaning IP address or address range.
Examples:
where the desired IP address is 1.1.1.1, the rule appears in filter.config like this:
dest_ip=1.1.1.1
where the desired IP address range is 1.1.1.1-1.255.255.255, the rule appears in
filter.config like this:
dest_ip=1.1.1.1-1.255.255.255
• url_regex, meaning a regular expression, which can appear anywhere in the URL (in other words, the
expression video will match with the URL mms://wham.wmt.com/msvideo.wvx).
Example: where the desired regular expression is video, the rule appears in filter.config like this:
url_regex=video
For url_regex, note that / is a special control character. se a backslash (\) to escape this, and some other
special control characters. For example, if you want to match the pattern cars/mustang, your rule would
be:
url_regex=cars\/mustang