Glossary

If there are terms you would like to see added to this glossary, please contact the course tutor (note: tbc = to be completed).

Asymetric Digital Subscriber Line (ADSL)

A type of Digital Subscriber Line connection which has a higher bandwidth in one direction than the other. Most DSL connections are ADSL with higher download than upload speeds.

Asynchronous

Not interactively, or in real time. For example, a letter sent via Royal Mail is asynchronous, since there is a significant (!) time lag between posting and receiving the letter. The postal service could not be used to hold a conversation in the normal manner because of this delay, and so is said to be asyncronous.

Digital Subscriber Line (DSL)

The most common type of broadband connection, which uses existing telephone wires to carry the connection into the home, thus eliminating the need for expensive rewiring.

Domain Name

The human-readable name for a collection of hosts (computers) on a subnet of the Internet - usually restricted to a company, organisation or individual. Exeter University's domain name is exeter.ac.uk (or ex.ac.uk for short), so all computers connected within it will have names ending in exeter.ac.uk, such as mail.ex.ac.uk, www.ex.ac.uk, and piglet.ex.ac.uk

File Transfer Protocol (FTP)

A protocol used to transfer files across a network, often used to upload web pages to a webserver. As FTP transfers passwords and data files unencrypted, it is better to use a secure alternative (such as SFTP or SCP) wherever possible.

HyperText Markup Language (HTML)

A markup language designed by Tim Berners-Lee as a simple, human- and computer-readable language for exchanging research data and documents.

HyperText Transfer Protocol (HTTP)

The protocol used by web browsers to request a particular web page from a webserver, and used by the server to deliver the page and associated media back to the browser for display.

Internet Assigned Numbers Authority (IANA)

The body that oversees the allocation of numeric Internet addresses. There is a complex scheme for allocating numbers to a particular subnet. Most organisations are allocated a specific range of addresses, which they decide how to use.

Internet Corporation for Assigned Names and Numbers (ICANN)

The body which oversees the allocation of domain names to organisations and companies. It governs the top level domains and delegates powers to other bodies who govern the individual ranges of names.

Internet Message Access Protocol (IMAP)

Internet Message Access Protocol is used to share mailboxes on the mailserver, allowing mail clients to access them without downloading messages to a local disk.

Internet Protocol (IP)

The Internet Protocol is the communications language that governs the basic transfer of data across the Internet. When coupled with TCP, it allows reliable transfers to take place.

Joint Academic NETwork (JANET)

The Joint Academic NETwork, the backbone of Internet connections that links all the major Universities in the UK.

Joint Information Services Committee (JISC)

The principle funding and organising body for network infrastructure in Higher and Further Education.

Local Area Network (LAN)

A term for the internal network of an organisation, building or home. A LAN is often used as an extension of the Internet, but may also carry other protocols which may be restricted from entering the wider Internet.

Mailing List

An email address which explodes a mail sent to it to the members of the list.

Network News Transfer Protocol (NNTP)

A protocol for efficiently delivering news and discussions across a large number of servers. Use of NNTP has been largely superceded by web-based news services and RSS.

News Aggregator

See Really Simple Syndication.

Nominet.UK

The body that allocated domain names within the United Kingdom.

Phishing

A method of capturing personal information by luring an unsuspecting user to a mock-up of a password entry page. Most often these are near-identical pages to an online bank or other commercial organisation, and the user is directed there from an email claiming that their bank account has been blocked or suspended. The mock-up page captures any usernames & passwords that are entered, through which the fraudsters can gain access to the user's account.

Post Office Protocol (POP)

The Post Office Protocol, a method used by an email client to download email from a mailserver.

Packet Sniffer

A program that allows a computer on a network to examine all the data that passes through a its particular network segment. It can be used to detect passwords and extract data where insecure protocols, such as SMTP, FTP or HTTP, are used.

Really Simple Syndication (RSS)

A web-based document format that summarises news articles, providing a method of accessing news that is convenient and quick. An RSS aggregator (or news aggregator) is a form of client software that collects and displays these summaries from multiple sources (hence, it aggregates news) that the user selects.

Request For Comment (RFC)

A document proposing a change or innovation in the structure, protocols or applications used on the Internet. These are the core documents through which the evolution of the Internet is discussed and decided. All RFCs are archived at rfc.net

Standard Generalised Markup Language (SGML)

A meta-language used to define other markup languages. The original definition of HTML was written in SGML.

Simple Mail Transport Protocol (SMTP)

Simple Mail Transport Protocol, a protocol used by mail servers and clients to transfer emails across the network.

Transmission Control Protocol (TCP)

TCP is a communications protocol that provides a reliable means of verifying whether a data transfer has taken place without data loss. It builds on the basic transfer properties of the Internet Protocol (IP), providing the core language of the Internet.

UKERNA

The UK Education and Research Networking Association, the principle funding body for network infrastructure in the UK academic world.

Uniform Resource Identifier (URI)

A unique reference to a (usually Internet-based) resource. A URI can indicate location (e.g. a URL) or merely identify a resource by name or number (e.g. an ISBN number for a book).

Uniform Resource Locator (URL)

A reference, such as that used to indicate the end-point of a hyperlink, that refers to the location of a particular resource on the Internet. e.g. http://www.ex.ac.uk/.