This page contains a list of technological words and explanations used on the Network Support pages. Close this window when finished.

A - E    F - J    K - O     P - T    U - Z

A - E 

• AIM - AOL Instant Messenger is AOL's person to person Internet chat service.
• ATM - technology running the network. The old 155Mb/s ATM backbone technology has limited capabilities, and although faster ATM protocols are available, they are expensive and no longer in vogue.
• ATM-Gigabit bridge - the peice of equipment that links the two network technologies (ATM & Gigabit) together. This is the unit that is causing most of the problems.
• Backbone - central spine or loop of the network - uses the fastest mode of connection (Optical Fibre) to move large amounts of data.
• Bridge - piece of equipment connects to network protocols e.g. ATM and Gigabit.
• Broadcast Storm - network is saturated by false messages sent out by a machine in error or deliberately by a hacker or virus doing a 'Denial of Service' attack.
• CANLMAN - Cumbria & North Lancashire Metropolitan Area Network.
• CLEO - the Cumbria and Lancashire Education network.
• CISCO - company supplying network switches.
• Comms Room - a room (or cupboard) full of network equipment e.g. switches and hubs.
• Core switches - see Switches.
• Denial of Service Attack - hackers and/or viruses sometimes attempt to bring down servers and networks by sending large numbers false requests for information to servers. If too many requests are made the sever may fail.
• DHCP - Dynamic Host Configuration Protocol - allocates a new IP number to a PC when it logs onto the network. This means that each PC doesn't have to have its on IP address.
• Duplex - 'Full Duplex' means information travelling over a link at full speed in both directions. 'Half Duplex' - infromation travells faster in direction than the other.
• Ethernet - superseded network technology (pre ATM).
• Exchange - is Microsoft's fully featured email server. Features of Microsoft Exchange include an appointments calendar and contacts database. Staff at the University are on an Exchange email system.

F - J 

• Feeds - general term for cables or possiblly other modes of transmission. Feeds have varoius different speeds measured in Mbits.
• Fibre or Fiber - see Optical Fibre.
• FTP - File Transfer Protocol - a service on the Internet that allows you to transfer files from a PC to a FTP server (or between FTP servers). FTP is in fashion again as sending files as attachments in email is problematic due to virus problems. See local web pages about FTP.
• Gigabit - meaning #1 - the newer technology running the network - SuperJANET4 is now IP-based, superseding the old ATM-based service with 2.4Gb/s (moving to 10Gb/s and onwards) Gigabit technology. This technology is based on Ethernet technology and offers higher throughput at lower cost.
• Gigabit - meaning #2 - gigabit is a measurement of speed equivalent to 1000 Megabits.
• Hub - the network cable from the back of your PC goes to a network point in the wall and from there goes to a 'hub'. The hub is then connected to a switch.
• ICMP - Internet Control Message Protocol is a protocol for reporting internal errors on the Internet.
• ICQ - 'I Seek You' - a way of getting in touch with people. ICQ is informal and not supported by ISS.
• IMAP - Internet Mail Access Protocol - the email protocol used by the Microsoft Exchange email system. IMAP is more secure than POP because it encrypts the username and password as they pass over the network. IMAP also ensures that your email is left on the server.
• IM - Instant Messenger - MSN Messenger and AOL Instant Messenger allow you to type directly to anyone else on the Internet using the service.
• IP - Internet Protocol - the language which is 'spoken' by computer on the Internet.
• IRC - Internet Relay Chat - system for talking (typing) to people from all over the world in 'chat rooms'. As you type, everyone else in the chat room can see you type, as the other people in the room type you can see their typing - instantly. Each chat room will have its own topic and rules. Programs used for IRC include 'mIRC'. IRC is informal and not supported by ISS.
• Jabbering Network Card - A 'Jabbering' network card is one that sends random bits of data out in no order or even in the correct format. This causes the equipment to become confused and can cause a vareity of different problems, most commonly the port where the card is plugged into disables itself or in rarer situations it can cause the stack to disable its link to the core of the network removing connectivity from everyone in that 'stack'.
• JANET - Joint Academic NETwork - the wide area network that connects the Universities in the UK. Also called SuperJANET.

K - O 

• LabNet - the PC Lab Network - PCs in Labs are not directly connected to the network.
• LAN - Local Area Network - the University network is a LAN.
• LANE - LAN Emulation - makes ATM look like the older Ethernet technology.
• Linux - a free, secure, reliable operating system, commonly used by computer enthusasts as an alternative to Windows. Linux was developed by Linus Torvalds to be like Unix but free. Linux is developed by a experts from round the world in their spare time.
• MBits - measurement of speed - Mega Bits - Million Bits per second. Common speeds are 10 Mbits for speed of a feed to a computer and 100 Mbits for a speed of an infrastructure feed.
• Media Converter - converts fibre into UTP. Fibre (or fiber) can carry data over longer distances than standard data cabling. Therefore we use fiber to get data to the comms cupboards and use a media converter to convert.
• Modem - MODulate DEModulate - translates computer digital data into sounds so that it can be transmitted down audio telephone lines and translates modulated sounds into digital data for use in the computer.
• MSN - MicroSoft Network - Microsoft's Internet offering which includes: various information sites, Hotmail, 'Groups' (formally 'Communities') which are bulletin boards, MSN Chat (which are IRC chat rooms) and 'Instant Messenger' for person to person chat. For some of these services you need a .net passport. If you have Hotmail you have a .net passport.
• NAT - Network Address Translation - the Residential Network is not on the Internet directly. It sees the residential network accesses the Internet through a server. NAT runs on this server to translate local private IP addresses to global IP addresses and vice versa. The NAT server provides access to ResNet users to Internet services that can't use the webcache e.g Instant Messenger services and IRC (Internet Relay Chat). For more details see the NAT Server Page.
• Network at Risk - weekly period (Tuesdays 8am till 10am) when network work is scheduled to be done. For a list of other scheduled downtimes.
• Optical fibre - high speed glass fibre cable connection which uses light to transmit data. Fibre (or fiber) can carry data over longer distances than standard data cabling.

P - T 

• POP - Post Office Protocol - sometimes referred to as 'POP3', is a way of communcating with a POP server which in turn is an email post office associated extensively used on Unix servers. The POP protocol is not as secure as the IMAP protocol. Always use IMAP where possible.
• Port - socket on the back of a computer, hub or switch.
• Protocol - loosly speaking a language or, more technically a 'set of agreed formats', by which to systems exchange information.
• RAS - Remote Access Service - service for staff to connect home PCs by modem to the campus network.
• ResNet - student Residential Network - all student residences have data points to connect to the network.
• Router - a smart switch that filters network traffic to reduce load on the system.
• Server, Network - PCs on the network that validiate usernames and passwords of people who logon to the network.
• Servers - computers, often a PCs, that provides services to workstation PCs. 'Services' provided by servers include: filestore, specialist printers and Internet Address translation.
• SMTP - Simple Mail Transfer Protocol - a basic email protocol, 'Sendmail' uses this protocol. SMTP has been largely superceded by POP3 and IMAP protocols.
• SSH - Secure SHell - SSH is a protocol for secure remote login and other secure network services over an insecure network.
• Stack - a rack of switches and routers etc.
• SuperJANET - a go faster version of JANET.
• SuperJANET 4 - the latest 'go faster' version of JANET.
• Switches - pieces of equipment that connect the network together. User computers are connected to 'edge switches' which are in turn connected to the 'core switches'. Network servers are also connected to the 'core switches'.
• TELNET - is a protocol that allows PCs to be terminals on Unix and other systems.

U - Z 

• Unix - secure, reliable operating system which is commonly used for servers. See also Linux.
• Unix Cluster - ISS provide a Unix service on a group on Unix servers known as the Unix Cluster.
• UTP  - Unshielded Twisted Pair - slower copper cable.
• WAN - Wide Area Network - e.g. the network that connects UK Universities (JANET).
• Workstation - any PC, or computer, on the network that you work on. The servers which provide user verification and other services are not 'workstations'.
• Webcache - stores web pages browsed by people on campus. Web browsers are setup to check the webcache first for web pages. As it is quicker to load a page locally (from the webcache) than to load it from the USA (for example). Using the webcache also saves money as the University is charged for trans-atlantic traffic. Follow the link to learn how to configure your web cache at Lancaster University.
• Worm - code that replicates itself from machine to machine by exploiting security weaknesses in email programs (or in server software).

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Last Updated: 10/02/09

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