Streaming Media Supplement sa2150 and sa2250

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Chapter 7 Configuring Media-IXT for RealNetworks
The allow and deny actions
For filter.config, you must assign one of the two following actions:
action=allow
action=deny
(The other possible actions in filter.config have no effect on Media-IXT.)
The example filter.config
rules below deny proxy access to all
deniedtome.com sites except for
vetted.deniedtome.com:
dest_host=vetted.deniedtome.com action=allow
dest_domain=deniedtome.com action=deny
Modifying the cache.config file to determine cacheability
To limit streaming media caching to specific URLs, you must specify caching rules in the cache.config
file located in Traffic Server’s config directory.
For cache.config, you must assign one of the two following actions:
action=never-cache
action=standard-cache
(The other possible actions in cache.config have no effect on Media-IXT.)
Caching rules apply to HTTP, RTSP, and MMS URLs. You can use the suffix secondary specifier with the
values .rm, .sdp, .asf or other file extensions to limit a rule to those particular file formats. You can also
use the scheme secondary specifier, along with tags where needed, to limit a rule to a particular streaming
format.
See the description of url_regex in the section about filter.config above; use of url_regex with
cache.config works the same way.
In the example below, the first rule allows RealNetworks content from
music.com
to be cached and the second
rule prevents .rm files from all other sites from being cached.
dest_host=music.com scheme=rtsp action=standard-cache tag=RNI
dest_domain=. suffix=.rm action=never-cache
Differences between forward and reverse proxy selective caching
For a reverse proxy deployment, selective caching rules must be written differently than for a forward proxy
deployment. That is because rules must be based on requested URLs after remapping has been applied. In
forward proxy, clients request the origin server hostname. In reverse proxy, clients request the advertised name
of the website, which Media-IXT then remaps to the origin server hostname. Observe the differences in the two
examples that follow.
A forward proxy cache.config example
Here is an example rule:
dest_host=foo.bar.com scheme=rtsp action=never-cache tag=RNI
This rule prevents Media-IXT from caching RealNetworks content hosted on the origin server foo.bar.com.
A reverse proxy cache.config example
Here is an example rule:
dest_host=back.door.com scheme=rtsp action=never-cache tag=RNI
Let us assume that:
• the advertised name of the website is foo.bar.com;