Numion homepage Measure your speed Measure your website Measure the time it takes to download any page on the internet. A collection of bandwidth calculators. SiteSpeed statistics for this website Copyright 2005 J.C. Kessels Goto Numion homepage Frequently asked questions Interesting Links Contact page, to report a problem or ask a question Copyright 2005 J.C. Kessels


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.