Backbone - Bytes

Backbone:
The very high bandwidth routes which join networks together. Currently the backbone is made up to OC-48 and OC-3 links.

Bandwidth:
The amount of throughput available to or used by a given connection.
For example, often ADSL is quoted as having a bandwidth of 512kbps, or modems as 56kbps (whilst this is the theoretical maximum bandwidth, in reality the atual throughput is normally less due to various overheads and contention ratios).
Whilst it is not a proper definition, many people use the word bandwith to convey the amount of data transfer in a given period of time.

Bit:
Binary Digit, the most basic form of data storage represented by a 1 or 0 (on or off)

Bitrate:
The rate of data transfer when a media file is being streamed measured in bits per second.

Bits per second:
The number of bit's which are being transfered each second.

Broadband:
The term given to high bandwidth connections. This definition is subjective, and there is no general concensus to a particular speed that it relates to. 512kbps ADSL and Cable-Modem connections are generally accepted as being broadband by the public, whereas Telecom's companies often consider it to relate to tens of megabits per second or abive.

Broadcast:
A stream sent out from a computer which may be received by a streaming server using a "pull".

Buffering:
The process of storing up a small amount of data in advance of playback so as to ensure constant playback and the integrity of a stream. This compensates for fluctuations in the available bandwidth on a given connection.

Byte:
A block of 8 bits of data.

Bytes per second:
The rate of data transfer measured in bytes per second. (This is not usually used when talking about streaming where the measure is normally in bits per second, kilobits per second or megabits per second).

Broadband

There is no true definition of what broadband is. This is primarily because data transfer speeds are constantly getting faster due to new technology.

Whilst an ADSL line may seem fast compared to traditional modems, it is only a fraction of the speed of what has traditionally been used for sending and receiving uncompressed video (155Mpbs).

Until recently most networks were running at 100Mbps, but now most ISP's are upgrading to Gigabit (1000Mbps) speeds.

Whilst this may seem fast enough for almost anything you can imagine, think about what happens when several thousand people want to watch a live broadband broadcast all at the same time!

In the above case we load balance lots of different machines accross different networks around the world!!!

Buffering

Even with a 512Kbps connection people encounter buffering problems when trying to watch a 300Kbps stream. There are several different reasons for this, the main one being that ADSL lines have a contention ratio.

This means that the 512Kbps is actually shared with other ADSL users, often up to 50 in total. If lots of users are all logged on at the same time and surfing the web, then you will probably not get 300Kbps all to yourself.