1-16
INTRODUCTION ORBAN
MODEL
1010
puters can simultaneously access. The users of a multicast have no control over
the media content. Multicasts are an efficient way to deliver the same mate-
rial to a group of people over a LAN, as only one copy of the stream is sent
over the network. (See Multicast on page 1-25.)
Because Opticodec-PC contains a multicast server, more than one listener can
connect to the same IP address without increasing network traffic. This is an
excellent way to deliver corporate or academic content to an internal audi-
ence or to stream radio stations to the staff at their computer workstations.
Unless your LAN contains a router that is not multicast enabled and that sepa-
rates the encoder from your listeners, you do not need to use a server to mul-
ticast within a LAN. For listeners to connect to your stream via a typical LAN,
they have to connect their decoder applications to the same local IP address as
the one you assigned to the output of Opticodec-PC.
Bandwidth Requirements
Streaming puts demand on your server system in a number of ways, the most impor-
tant being bandwidth. For example, three different unicast streams for different
purposes will attract different audiences with different network connectivity re-
quirements.
Stream Type
Attendance
Audicence
Connection
Speed
Total
Concurrent
Ban 20%
Total
Throughput
for 1 Hour
Distance Learning
100
20 kbps
2.4 Mbps
990 MB
Small Corporate Meeting
100
32 kbps
3.8 Mbps
17.1 MB
Medium Entertainment Stream
1000
48 kbps
57.6 Mbps
25.9 GB
Large Entertainment Stream
5000
48 kbps
288 Mbps
129.6 GB
Table 1-3: Bandwidth Requirements for Typical Network Streams
Even the smallest academic streams can generate huge numbers that require more
than a single E-1 or T-1 line to serve. Corporate and entertainment streams can
sometimes require multiple E-3 or T-3 lines, or even higher capacity to serve. Large
streams may even require more than one server to handle the necessary network
throughput. However, since Orban Opticodec-PC is bandwidth efficient, you are
able to serve a larger audience at a lower cost of operation with higher audio qual-
ity than with inferior older generation codecs.
Not all networks have 100% of their theoretical capacity available for data transfer.
You are practically limited to about 80% of theoretical maximum because of the
way TCP/IP traffic is handled on a network. For example, a 100 Mbps LAN is limited
to about 80 Mbps. In addition to this practical limitation, you may want to allot ad-
ditional bandwidth for other tasks, such as file transfers and backup procedures. An
additional 10% should suffice. Generally, a good equation for calculating the practi-
cal capacity of a network is:
Practical Network Capacity
= Theoretical Maximum * 70%
Maximum Simultaneous Streams
= Practical Network Capacity / Stream Bitrate
