Streaming Media Supplement sa2150 and sa2250

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Chapter 4 Understanding Media-IXT and WMT
WMT streaming deployments based on MMS transparency
Media-IXT supports full MMS transparency with use of a layer 4 switch or a WCCP2 router. WMT metafile
rewriting and HTTP transparency can each be independently configured on or off. Various combinations of
these three features are possible in deploying Media-IXT to stream WMT content.
Here is one possible deployment scenario, which needs neither WMT metafile rewriting nor an HTTP server
for WMT streaming:
• MMS transparency is provided by a layer 4 switch or WCCP2 router, and turned on in Media-IXT’s
Adaptive Redirection Module.
• Port 1755 traffic is transparently redirected to Media-IXT.
In this kind of deployment, you would take the differences between versions of Windows Media Player into
account.
• Windows Media Player 6 can use Media-IXT as an HTTP proxy, by being configured explicitly or being
instructed to use the browser's proxy settings.
• Windows Media Player 7 can use Media-IXT as an MMS proxy as well as an HTTP proxy.
Basing your deployment on MMS transparency has the advantage of avoiding some limitations of WMT
metafile rewriting. For example:
• Occasionally a WMT metafile is too complex to be rewritten, which prevents Media-IXT from proxying or
caching content associated with that metafile.
• If you use java or javascript to embed a Windows Media Player session in an HTML page, there can be no
transparent proxy caching of that session unless your deployment includes MMS transparency. For simple
explicit proxy caching deployments, Media-IXT is unable to handle such embedded URLs for WMT
streaming.
Figure 4-9. WMT reverse proxy caching example (concluded)
Media-IXT
http://w w w.pix.com/
10.10.10.10
Windows
Media Server
http://source.pix.com/
11.11.11.11
Client browser
with Windows
Media Player
Web Server
htt p:/ / relay.pix.com/
7
metadata
8
7
9
udp
6
mms
6
7
8
9
mms request for rewritten media content URL:
mms://www.pix.com/funnymovie.asf
map rule locating the origin server:
map mms://ww w.pix.com/ mms://source.pix.com/
Windows Media Player requests the rewritten media content URL from Media-IXT.
Using a map rule, Media-IXT finds, and opens a connection to, the origin Windows Media server.
Media-IXT uses metadata to determine if the streaming content is in cache and fresh.
Since funnymovie.asf is already cached and fresh, Media-IXT streams it to the browser.