Apple QuickTime Technical Information download pdf (Page 60)

60 Chapter 6 Setup Example

• Windows can cause lighting problems. For more control, you should be able to draw

the blinds and supplement room lights with a portable lighting kit that can be

quickly set up for a live session.

Step 2: Prepare the Network

Check that there is an Ethernet connection to the room where the live broadcast is to

take place. Install, repair, or replace cables and connectors as needed, using high-

quality materials.

Bear in mind that streaming—especially live streaming—can make heavy demands on

network resources, especially available bandwidth. To ensure that the network can

handle the extra load, it may be necessary to do some or all of the following:

• Determine the capacity of the existing network and calculate the anticipated

additional traffic generated by live and on-demand streaming.

• Draw a map of bandwidth segments on your network, listing the capacity between

all points.

• Determine which applications are used in your network, their use patterns, where

they are hosted, and the bandwidth they normally use during peak and off-peak

times.

• Based on the configuration and capacities of your network, select the appropriate

place to install your streaming server, avoiding potential bottlenecks.

• If necessary, add capacity to the network (additional T1 lines, routers, switches, and

so on) to handle the anticipated maximum number of concurrent viewers of live

broadcasts in addition to other peak network traffic.

Note: A typical local network provides bandwidth internally of 10–100 Mbps. In

contrast, a T1 line provides only about 1.5 Mbps of bandwidth.

T1 lines work fine for HTTP and FTP, where the requests are either short-lived or are

not time sensitive, but streaming is much more demanding. With streaming you can’t

slow things down—the data has to be transferred at least as fast as the original

content data rate in order to deliver streams.

For this example, we will assume a maximum of 10 concurrent viewers, half on the

local network and half on the Internet, and a bit rate for each unicast stream of

approximately 256 kilobits per second (Kbps). The peak extra bandwidth needed is

then about 3.2–3.3 megabits per second (Mbps). This estimate includes an extra

margin of 25–30 percent for unplanned network congestion and peaks in the

transmitted streams that can occur for various reasons.

Step 3: Set Up Your Streaming Server

An administrator computer must be set up before you can configure and manage your

streaming server if, as in this example, the streaming server is running headless. For

information on setting up an administrator computer, see Mac OS X Server Getting

Started for Version 10.4 or Later (included on a Mac OS X Server install disc).

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Apple QuickTime Technical Information Page 60