|
| Glossary
of Selected Terms (I-L) |
| |
| Section
I |
| IANA
(Internet assigned numbers authority) A governing authority
of the Internet, responsible for overall control and assignment
of protocol-relevant configuration information (e.g. IP protocol
field values, TCP/UDP port numbers, protocol parameter value
assignment, etc.). |
| IEEE
802 A technical committee and standards documentation
covering data and wireless networking in LANs (local area networks)
and MANs (metropolitan area networks). |
| IEEE
802.2 The IEEE standard for the layer 2 (datalink)
protocol used in local area networks (LANs). The protocol is
usually referred to as LLC (logical link control). |
| IEEE
802.3 The IEEE standard defining the physical layer
of the ethernet LAN. There are a large number of different variants
(see Appendix~5). |
| IEEE
802.5 The IEEE standard defining the physical layer
of the token ring LAN. |
| IETF
(Internet engineering task force) The main organisation
and working group responsible for defining Internet standards
and issuing RFCs. |
| interface
A standardized mechanical, electrical and protocol format used
to connect two or more pieces of equipment together. |
| interference
A signal impairment caused by the interaction of an unwanted
adjacent signal. |
| Internet
A large public `shared network' based upon the Internet protocol
(IP). |
| InterNIC
The Internet network information centre. InterNIC provides for
Internet domain name registration services. |
| intranet
A private (usually enterprise-internal) data network based upon
similar equipment to that used in the Internet. Such networks
use the Internet protocol (IP) but are either isolated from
the public Internet or connected only by means of special controlled
connection points (e.g. firewalls). |
| IP
(Internet protocol) The layer 3 (network) protocol
used in Internet and router-based data networks. |
| IP
address The network address used to identify the intended
destination of a data message sent across the Internet or some
other IP-based network. IP addresses intended for use with IPv4
have the format d.d.d.d where each d is a decimal value between
0 and 255. IPv6 addresses, on the other hand, have the form
hhhh:hhhh:hhhh:hhhh:hhhh:hhhh:hhhh:hhhh where each h is a hexadecimal
value in the range 0 to F. |
| IPv4
(Internet protocol version 4) The version of the Internet
protocol defined in RFC 791 (issued in September 1981). |
| IPv6
(Internet protocol version 6) The version of the Internet
protocol defined in RFC 2460 (issued in December 1998). IPv6
is similar to IPv4 in its basic functioning and architecture,
but was specifically designed to provide a much larger IP-addressing
space and to cope with the specific needs of modern `flow-oriented'
communication (e.g. real-time voice, video and multimedia).
|
| ISDN
(integrated services digital network) The digital telephone
network. |
| ISO
(International Organization for Standardization) An
international organisation, based in Geneva, Switzerland, responsible
for coordinating and publishing international standards. |
| ISP
(Internet service provider) A public telecommunications
provider to whom businesses and private individuals may subscribe
for provision of network access to the Internet. |
| ITU
(International Telecommunications Union) An agency
of the United Nations (UN) set up in 1934. The world's foremost
regulator of radio spectrum and technical standards for public
telecommunications networks |
| ITU-T
(ITU Standardization sector) A body within ITU responsible
for the development of technical `standards' (called `recommendations')
which are widely used as the basis for international telecommunications
technology and networks. |
| ITU-T
recommendation A technical `specification' of the ITU-T,
however, not having official `standards' status, and not being
mandatory. |
| Section
J |
| jitter
Jitter arises when the timing of the pulses of a digital signal
varies slightly, so that the pulse pattern is not quite regular.
The effects of jitter can accumulate over a number of regenerated
links and result in received bit errors. |
| Section
L |
| LAN
(local area network) A type of data network allowing
the interconnection of computer devices within a relatively
restricted area, typically lying along a spine or circle of
length less than about 100--500 metres. LAN (local area network)
A type of data network allowing the interconnection of computer
devices within a relatively restricted area, typically lying
along a spine or circle of length less than about 100--500 metres.
|
| latency
The propagation delay encountered by a packet of data while
traversing a network. |
| layered
protocol Individual protocols are generally designed
to carry out a single control or data transfer function, as
two peer devices communicate with one another. A number of different
protocols are combined in a modular and layered fashion to undertake
all the required communications functions. The combination of
protocols is termed the protocol stack. |
| line
code The technique used when actually transmitting
a digital signal onto a transmission line. The line code helps
to ensure the synchronisation and correct receipt of data. |
| LLC
(logical link control) The layer 2 (datalink) protocol
used in conjunction with local area networks (LANs). |
| |
