- 802.1x
- An Ethernet standard for authenticating both
the device that you are connecting to, to the user; and the user to the
device. This allows the user to verify that the device that they
are connecting to really is the device that they think it is. E.g. when
you connect to http://www.essex.ac.uk, that you really are connecting
to the University of Essex's web site, and not someone or some thing
impersonating the University of Essex. 802.1x also authenticates
the user to the device or service, so the device or service knows who
the user really is.
- 802.11a
- An Ethernet standard for wireless networking,
operating in the 5GHz range providing network connection speeds up to
54Mbps. Due to the nature of wireless networks
the typical throughput that each user will get is only 23Mbps.
- 802.11b
- An Ethernet standard for wireless networking,
operating in the 2.4GHz range providing network connection speeds up to
11Mbps. Due to the nature of wireless networks
the typical throughput that each user will get is only 4Mbps.
- 802.11g or 802.11b/g
- An Ethernet standard for wireless networking,
operating in the 2.4GHz range providing network connection speeds up to
54Mbps. As the 802.11g standard is based on the
802.11b standard, these two standards interfere with
each other. The result is that if any devices are operating on the
802.11b standards, then all devices in the vicinity slow down to the
802.11b speed of 11Mbps maximum. Due to the nature of wireless
networks the typical throughput that each user will get is only 19Mbps or
4Mbps if an 802.11b device is near by.
- 802.11n (Throughput Enhancements)
- An Ethernet standard for wireless networking,
operating on both the 2.4GHz and 5GHz ranges providing network connection
speeds up to 248Mbps. Due to the nature of
wireless networks the typical throughput that each user will get is only
74Mbps. 802.11n is not another distinct networking system, it is a
collection of throughput enhancements to the existing
802.11a and/or 802.11b/g.
- 10Base2
- A technical name for a particular type of Ethernet
with a speed of 10Mbps.
- 10Base5
- A technical name for a particular type of Ethernet
with a speed of 10Mbps.
- 10BaseT or 10BaseFX
- A technical name for a particular type of Ethernet
that we use here with a speed of 10Mbps.
- 100BaseTX, 100BaseFX or fast Ethernet
- A technical name for a particular type of Ethernet
that we use here with a speed of 100Mbps.
- 1000BaseTX, 1000BaseSX, 1000BaseLX, 1000BaseLH or
gigabit Ethernet
- A technical name for a particular type of Ethernet
that we use here with a speed of 1000Mbps or
1Gbps.
- 10 gig or 10 gigabit Ethernet
- A technical name for a particular type of Ethernet
with a speed of 10,000Mbps, or 10Gbps.
- Access Point or AP
- A networking device that provides the base station for wireless
networking. Access points may provide any combination of
802.11a, 802.11b,
802.11g or 802.11n.
- AES
- Advanced Encryption Standard. The name
given to a particular method of encrypting data.
- ATCP
- AppleTalk Control Protocol. The name
given to the control protocol for using Appletalk
over PPP links.
- ATM
- Asynchronous Transfer Mode. ATM was heralded as
the network to end all networks because it is flexible enough to be used as
a LAN, a MAN, a RAN
or a WAN, with scaleable speed. In practice it
turned out to be too complex, and therefore too expensive to be of great
practical value. ATM is now used by some research sections of the
University.
- AppleTalk
- A type of network protocol proprietary to Apple Computers. Cf.
IP and IPX.
- AUI
- Attachment Unit Interface. The name given to an
interface used on thick Ethernet.
- bandwidth
- The amount of frequency band available for data transmission, related
to transmission speed, though the two are not the same. For digital data
transmission this is usually (erroneously) measured in bps
(which is actually the transmission speed).
- Baud
- The speed of a serial connection (in bits per second) named after
Emile Baudot who invented the Baudot code for telegraphy.
- bps
- Bits Per Second. Also kbps - kilobits per second
= 1000 bps; Mbps - Megabits per second = 1000 kbps or 1,000,000 bps; Gbps -
Gigabits per second = 1000 Mbps or 1,000,000,000 bps; etc. A measure of
the speed of data transmission.
- broadband
- A telephony term meaning a service that provides a
bandwidth higher than a normal telephone line.
- CDDI
- Copper Distributed Data Interface. A type
of Local Area Network (LAN) based on copper wires.
Cf. FDDI.
- CLNS
- Connection Less Network Service. A type
of protocol used on networks where data is broken into
packets, each of which is routed independently to its
destination, thus packets can get lost (corrupted), duplicated, or arrive
out of sequence, e.g. Ethernet. Cf.
CONS.
- CONS
- Connection Oriented Network Service. A
type of protocol used on networks where a path is set-up between two devices
at the start of communication, and is removed once the communication is
ended. Data is usually broken into frames, which
are not duplicated, but may be lost (corrupted) and cannot arrive out of
sequence. Cf. CLNS.
- e-mail
- Electronic mail.
- Ethernet
- A type of Local Area Network (LAN) based (mostly) on
copper wires.
- FDDI
- Fibre Distributed Data Interface. A type of
Local Area Network (LAN) based on glass fibres. Cf.
CDDI.
- fibre or optical-fibre or fibre-optic or glass
- A fibre-optical cable capable of carrying network traffic as light
waves. Typically fibre has a much higher bandwidth
than copper cabling and is less susceptible to, and causes less,
interference.
- Frame
- A frame is a collection of pieces of information that is transmitted as one
entity. A Frame usually has some variety of header showing what type of,
and how much, data it contains, and a check-sum on the end such that corruption
of the data can be detected. Frames are usually transmitted over
CONS networks. Cf. Packet.
- ftp
- File Transfer Protocol. A higher level protocol,
used in conjunction with TCP/IP to enable files of data to
be transferred between hosts.
- Gateway
- A device that connects two different types of network together.
- Gbps
- See bps.
- IEEE
- The Institute of Electrical and Electronics
Engineers. The organisation that defines the standards for (among
other things) Ethernet. These (Ethernet) standards
are all of the form 802.XXX, where XXX defines the particular part of the
Ethernet standard.
- IP
- Inter-net Protocol. A type of communications protocol used
mainly, but not exclusively, on Ethernet. Cf.
AppleTalk and IPX.
- IP address
- An address used as part of IP. There are two forms: version
4, of the form www.xxx.yyy.zzz, where the four numbers, www, xxx, yyy, and zzz are
in the range 0 to 255; and, version 6, of the form s:t:u:v:w:x:y:z, where the eight
numbers s, t etc. are hexadecimal and in the range 0 to FFFF. At Essex all
our addresses are version 4 and usually start 155.245.
- IPCP
- IP Control Protocol. The name given to the control
protocol for using IP over PPP links.
- IPX
- IPX is the name given to the set of protocols used by
Novell's Netware for communication between PCs over
Ethernet. Cf. AppleTalk and
IP.
- IPXCP
- IPX Control Protocol. The name given to the control
protocol for using IPX over PPP links.
- ISP
- Internet Service Provider. A company that provides
connectivity services, usually to the global Internet and usually via a
modem or broadband connection.
- JANET
- Joint Academic NETwork. A network covering most
education and research establishments in the UK, with connections to other
country's similar networks and to other Internet service company's
(ISP) networks. JANET is operated by
JANET(UK).
- JANET(UK)
- A company wholly owned by the education and research community charged with the
responsibility to operate JANET.
- kbps
- See bps.
- LAN
- Local Area Network. A term used to describe a network
with limited physical range (usually about 2Km). Cf. MAN,
RAN and WAN.
- leased line
- A permanent network connection between two points provided by a telecommunications
company, hence it is usually leased.
- local
- Something connected to, or a service provided by, the piece of equipment you are
sitting in front of i.e. you do not need to use a network in order to use the
facility.
- MAC address
- Media Access Controller address. The unique address
belonging to a device connected to an Ethernet network.
- MAN
- Metropolitan Area Network. A term used to describe a
network suitable for an area about the size of a city. Cf.
LAN, RAN, and WAN.
- MAU
- Media Attachment Unit. A device to connect an
AUI to Ethernet.
- Mbps
- See bps.
- MNP
- Microcom Networking Protocol. A type of error
correcting/compression protocol. The error correction protocols add some
overheads, but can give some data compression. This means that the overall data
rate varies between about 80% and 120% of the basic transmission speed, depending on the
error correction level used. Currently there are four levels of error correction
designated MNP1 to MNP4. MNP5 is a data compression protocol.
- Modem
- MOdulator/DEModulator. A device for allowing digital data to be
transmitted over audio links (e.g. analog telephone lines).
- Modem Server
- See Terminal Server.
- MTU
- Maximum Transmission Units. The maximum number of
transmission units (usually bytes) that can be transmitted in a single
packet across a network.
- Network
- A collection of wires, fibres, and equipment used to effect communication between a
number of nodes (usually computers).
- NFS
- Network File System. A protocol to allow file systems to be
shared between several computers connected by a network using IP.
- Novell
- Novell is the name of a company that invented a particular type of networking
protocol. This protocol is often referred to as Novell, or Novell Netware. See
also IPX.
- Packet
- A packet is a collection of pieces of information that is transmitted as one
entity. A packet usually has some variety of header showing what type of, and how
much, data it contains, and a check-sum on the end such that corruption of the data can be
detected. Packets are usually transmitted over
CLNS networks. Cf. Frame.
- POP
- Post Office Protocol. A protocol that allows mail to be
transferred from one computer to another. This protocol is used to get mail from
a server (cf. SMTP), and is used in conjunction with
TCP/IP. Any numbers denote the version of the protocol, higher
numbers generally being backward compatible with the lower numbered versions. I.e.
a POP3 server will work with a POP1 client, but a POP1 server will not work with a POP3
client.
- PPP
- Point to Point Protocol. A type of communications protocol
that allows other protocols (e.g. IP, IPX, Appletalk) to be carried over
serial lines.
- Protocol
- A protocol is a particular format for data used on a network, it is, if you like, the
language used for communications.
- PSK
- Pre-Shared Key. This is the name given to an encryption key
for certain communication methods, most notably wireless networks.
- PSS
- Packet Switched System. A old type of network operated in
the UK by British Telecommunications plc. connecting (a decreasing) number of commercial
organisations.
- RAN
- Regional Area Network. A network that operates around a
moderate size geographical area, roughly equivalent to a region (e.g. East-Anglia) in a
country. Cf. LAN, MAN, and
WAN.
- rcp
- Remote CoPy. A program to provide file transfer.
- Remote
- Something connected to, or a service provided by, another computer requiring use of
the network in some way to have the use of this facility. Physical locations of
equipment do not matter; two items could be in the same room, and yet be
"remote" from each other.
- RJ45
- The technical name for the structured wiring
connectors.
- rlogin
- Remote LOGIN. A program to provide an interactive connection to a
remote service.
- Router
- A device that (effectively) connects to several (usually IP) networks
of the same type, and therefore
needs to sort network traffic, depending on destination, in order to pass it to the correct
network.
- rsh
- Remote SHell. A program to provide a means of executing commands on a
remote host without the need to (r)login.
- SDH
- Synchronous Digital Hierarchy. A method used for multiplexing
many circuits with a low bit rate onto fewer circuits with a higher bit
rate, and vice-versa (de-multiplexing). Used primarily in the telecommunications
industry to carry telephony traffic. This network can also be used to carry
IP traffic.
- Serial line, serial link or serial connection
- A simple point-to-point connection for low speed communication.
- SLIP
- Serial Line Inter-net Protocol. The name used for
IP running over a serial line.
- SMTP
- Simple Mail Transfer Protocol. This is a protocol used to
transfer mail from one computer to another. It works in conjunction with
TCP/IP, and is usually used to give (or send) mail to another
computer. Cf. POP.
- ssh
- Secure SHell. An application similar to telnet,
but the traffic it passes over the network is encrypted. This prevents eavesdropping
on passwords and other sensitive data.
- SSID
- Service Set IDentifier. This is the name by which a wireless
network service is known.
- Structured wiring
- A term used to describe a particular way of installing network wires in
buildings. Sometimes (incorrectly) used as another name for
10BaseT because 10BaseT uses structured wiring.
- SuperJANET
- SUPER Joint Academic NETwork. A network covering many
education and research establishments, a faster version of JANET.
- TCP or TCP/IP
- Transport Control Protocol. (Usually referred to as TCP/IP) a
communications protocol used in conjunction with IP.
- telnet
- A higher level protocol, used in conjunction with TCP/IP, to provide
an interactive connection to a remote service.
- Terminal Server (Modem Server)
- A piece of equipment that allows serial line devices to
connect to a network. Simple terminal servers only allow dumb
terminals (perhaps via modems and telephone lines) something like
telnet access. Sophisticated terminal servers allow
(semi-)intelligent terminals (e.g. PCs) to connect to the network using higher-level
protocols (e.g. PPP). If connections are only via modems, then
this equipment may also be referred to as a modem server.
- Thick Ethernet, or Thicknet
- A term used to describe 10Base5.
- Thin Ethernet, or Thinnet
- A term used to describe 10Base2.
- Throughput Enhancements (WiFi)
- See 802.11n above.
- Tree
- A topological term describing the way network components are connected.
- Twisted pair
- A term used to describe structured wiring.
- UKERNA
- United Kingdom Education and Research Networking
Association. The old name for JANET(UK).
- V.xx
- V.xx is used to denote various types of communication standard. Some are for simple
serial line communication (e.g. V.24, otherwise known as
RS232), others are for modem communication (e.g. V.21, V.22,
V.23, V.32), and others are for special uses (e.g. V.42, an error correction
protocol). Sometimes these standards are up-dated, and changed slightly, then they
have bis added to the end (e.g. V.42bis a data compression protocol).
- WAN
- Wide Area Network. A term used to describe a network capable
of covering a large area, like a country, or the world. Cf. LAN,
MAN, and RAN.
- WiMax
- The name for a type of wireless network connection designed to cover a large area at a
high speed. This technology is still very young, so not much uses it.
- Wireless, WiFi or Radio ethernet
- Wireless Ethernet is a means of connecting nodes to a network using
radio signals. This provides several advantages, but has several
disadvantages too. The advantages are that wires do not need to be
run around the place, and that computing devices can be used on the move.
The disadvantages are that the wireless connections are nowhere near as
reliable, they provide a much slower connection, and are inherently
insecure. As a result wired connections should be used wherever
possible, and wireless connections should only be used where a temporary
or mobile connections are required.
- Wireless Router
- A networking device that is a combination of an access point
and a router. These devices are usually used in private
homes where client PCs can be anywhere in the house (and thus use
WiFi to connect), and the network is a
broadband connection provided by an ISP.
- WPA or WPA2
- WiFi Protected Access is a protocol for connecting to wireless
networks that encrypts data in both directions in order to prevent
eavesdroppers from
being able to obtain the information as it passes over the wireless. WPA2 is a
later protocol that implements a better standard of security.
- Xmodem, Ymodem,
Zmodem
- These are types of protocol used to transfer files over
serial links, really intended for modem
links. They contain error checking, and re-transmission of bad data to ensure
correct transmission of the file(s). Which protocol you use depends on the type of
file(s), how many files, and the quality of the modem link.
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