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Glossary
- Throughput
- The amount of actual user data (payload) transmitted per second without the
overhead of protocol information such as start and stop bits,
TCP/IP overhead, HTTP headers, and such.
Throughput can vary, it depends on things like bandwidth, latency,
payload size, packet size, network load, number of hops, and others.
The higher your throughput, the faster you can surf the internet.
- Bandwidth
- The maximum amount of raw data that can be transmitted per second,
usually expressed in bits or bytes per second.
It's a fixed property, calculated rather than measured. In a network
the bandwidth is the highest speed of the slowest component.
- Speed
- Speed usually means "throughput" (see above), but depending on context can
also mean "bandwidth". For example, when you measure your speed it's
"throughput", but in an advertisement by a provider it's
"bandwidth".
- Latency
- The minimum time a network needs to send the smallest possible amount
of data. Latency depends on things like line speed and the receive and
retransmit delay in routers and modems. A low latency indicates a high
network efficiency.
- Registry optimization
- There are many programs available that will "optimize your registry".
They change network-settings deep inside the operating system of your
computer in an attempt to raise your speed.
For the average user the default settings are good enough and there
will be no (noticeable) gain, but these programs can be useful in special
cases.
- Speed accelerators
- Accelerators such as Propel, ProxyConn, Onspeed, VroomSpeed, and others
achieve a speed gain by compressing everything. Things are smaller and
therefore load faster. This only helps on compressable data such as text and
images, not on already compressed data such as ZIP and MPEG.
- bit
- Contraction of the term "BInary digiT". The smallest unit of information a computer can
process, representing one of two states (usually indicated by "1" and "0").
Bit's are usually combined into larger units, such as the byte (8 bits).
- byte
- A group of adjacent binary digits that a computer processes as a unit to form a
character such as the letter "z". A byte consists of eight bits.
- bps / Bps
- Bits per second and Bytes per second,
used to express how fast data is moved from one place to another.
A "28.8 modem" can move 28,800 bits per second (not counting overhead).
The terms "kilo", "mega", "giga", and "tera" are powers of 1000, not 1024
as is customary when describing memory and harddisk sizes.
| bps |
bits per second |
1 bit per second |
| Bps |
bytes per second |
8 bits per second |
| Kbps |
kilobits per second |
1,000 bits per second |
| KBps |
Kilobytes per second |
8,000 bits per second |
| Mbps |
Megabits per second |
1,000,000 bits per second |
| MBps |
Megabytes per second |
8,000,000 bits per second |
| Gbps |
Gigabits per second |
1,000,000,000 bits per second |
| GBps |
Gigabytes per second |
8,000,000,000 bits per second |
| Tbps |
Terabits per second |
1,000,000,000,000 bits per second |
| TBps |
Terabytes per second |
8,000,000,000,000 bits per second |
| analog modem |
28.8 Kbps |
| analog modem |
33.6 Kbps |
| analog modem |
56 Kbps |
| ISDN (1 channel) |
64 Kbps |
| DS0 |
64 Kbps |
| ISDN-2 |
128 Kbps |
| DS1, T1 |
1.544 Mbps |
| ISDN-32, E1 |
2.048 Mbps |
| ADSL |
8 Mbps up and 1 Mbps down (unthrottled) |
| 10Base-T (Ethernet LAN) |
10 Mbps |
| ATM25 |
25.6 Mbps |
| E3 |
34 Mbps |
| T3 |
45 Mbps |
| OC1 |
51.84 Mbps |
| 100Base-T (Ethernet LAN) |
100 Mbps |
| OC3 |
155 Mbps |
| OC12 |
622 Mbps |
| OC48 |
2.4 Gbps |
| OC192 |
10 Gbps |
- Baud
- In common usage the "baud rate" of a modem is how many bits it can send or receive
per second. Technically, "baud" is the number of times per second that the carrier signal
shifts value.
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