Streaming Media Supplement sa2150 and sa2250

11
Chapter 2 Media-IXT Deployment Scenarios
Reverse proxy of multiple origin servers
When Media-IXT performs reverse proxy for several different origin servers, and should not service traffic for
any other origin servers, reverse proxy configuration is combined with selective caching (see “Understanding
selective caching” on page 15) in a special way. Configuration details appear in the configuration chapters for
each streaming format.
Server farms
A group of origin servers with some sort of load-balancing device between them and the Internet is one form
of server farm.
Media-IXT can perform forward proxy caching for a server farm. Performing reverse proxy is not always
practical; the details vary between streaming formats, and appear in the configuration chapters for each
streaming format.
Simultaneous transparent and explicit forward proxy caching
Configuring Media-IXT to perform transparent and explicit forward proxy simultaneously is not uncommon.
Here is an example:
• A corporate intranet has a client base of one thousand desktops, whose client browsers have been explicitly
configured to use Media-IXT as a forward proxy cache.
• Later, the company expands, adding three thousand new desktops.
• The company chooses to purchase a layer 4 switch to implement transparent forward proxy caching, rather
than configure three thousand new browsers.
• The original 1000 browsers remain configured for explicit proxy caching, though. Reconfiguring them to
no longer use Media-IXT as a proxy would be time-consuming and logistically difficult.
The solution is simply to configure Media-IXT for transparent forward proxy caching. This takes care of the
3000 new desktops, and does not interfere with the explicit proxy caching required by the original 1000 clients.
The original clients remain configured as before. Media-IXT performs transparent and explicit forward proxy
caching simultaneously. Figure 2-3, below, shows such a deployment in a simplified way.
Figure 2-3. Simultaneous transparent and explicit proxy caching
Me ia-IXTd
request addressed to Media-IXT
request addressed
to an Origin Server
browser
is explicitly
configured to
use Media-IXT
as a proxy
browser
is not
configured
to use a
proxy
client
client
L4 Switch
(transparency device)
detects
port 80 (http)
traffic, and
redirects it to
Media-IXT
Origin Server
Origin Server
To Other
Origin Server
Origin Server