i960cf - The Intel
960 family is a RISC based processor designed for embedded applications. The
"cf" series does not allow for dual SCP operation.
i960ha - The Intel
960 family is a RISC based processor designed for embedded applications. The
"ha" series pushes performance to more than 80 MIPS and allows for dual SCP
I/O Module -
Marconi's interface cards for the LAX-20 LAN Access Switch, designed to connect
Ethernet, Token Ring, and FDDI LANs to ForeRunner ATM networks.
I&R (Installation And
Repair) - The telephone company department responsible for these jobs.
IC (Integrated Circuit)
- A single electronic device that contains hundreds of thousands of previously
separate (discrete) components. The “computer on a chip” is a special purpose
ICD (International Code
Designator) - One format of ATM Addressing, it is administered by the
British Standards Institute. Identifies an international organization
responsible for the NSAP structure (in Marconi's case the hex 0005 identifies
the US Government). The registration authority under hex 0005 is the National
Institute of Standards and Technology (NIST) who has delegated the General
Services Administration (GSA) to register AA identifiers. The digits are
encoded in BCD syntax. (2 octets)
ICMP (Internet Control
Message Protocol) - The protocol that handles errors and control
messages at the IP layer. ICMP is actually a part of the IP protocol layer. It
can generate error messages, test packets, and informational messages related
ICR (Initial Cell Rate)
- For ABR, the rate at which a source is allowed to start up following an idle
IDI (Initial Domain
Identifier) - The Initial Domain Identifier can be either a 2-byte
data country code (DCC) value as describe in ISO 3166, a 2-byte international
code designator (ICD) as maintained in ISO 6523 by the British Standards
Institute, or and E.164 number.
IDP (Initial Domain Part)
- Specifies the authority allocating the NSAP address.
IDU (Interface Data
Unit) - The unit of information transferred to/from the upper layer in
a singlesize=+0>interaction across the SAP. Each IDU contains interface
control information and may also contain the whole or part of the SDU.
IE (Information Element)
- An information bearing entity that is encoded to define specific parameters
associated with establishing a contract. UNI signaling messages are comprised
of many Information Elements.
IEE (Institution of
Electrical Engineers) - The U.K. body for professional electrical
IEEE (Institute of
Electrical and Electronics Engineers) - the world's largest technical
professional society. Based in the U.S., the IEEE sponsors technical
conferences, symposia & local meetings worldwide, publishes nearly 25% of
the world's technical papers in electrical, electronics & computer
engineering, provides educational programs for members, and promotes
IEEE 802 -
Standards for the interconnection of LAN computer equipment. Deals with the
Data Link Layers of the ISO Reference Model for OSI.
IEEE 802.1 -
Defines the high-level network interfaces such as architecture, internetworking
and network management.
IEEE 802.1d Spanning Tree
Bridging - IEEE standard for bridging; a MAC layer standard for
transparently connecting two or more LANs (often called subnetworks) that are
running the same protocols and cabling. This arrangement creates an extended
network, in which any two workstations on the linked LANs can share data.
IEEE 802.1p -
Defines Standard VLANs
IEEE 802.1q -
Defines Standard VLANS, a.k.a. VLAN tagging.
IEEE 802.2 -
Defines the Logical Link Control interface between the Data Link and Network
IEEE 802.3 -
Defines CSMA/CD (Ethernet).
IEEE 802.3u -
Defines 100 BaseT Ethernet.
IEEE 802.3x -
Defines full-duplex flow control.
IEEE 802.3y -
Defines full-duplex flow control.
IEEE 802.3z -
Defines MAC for 1000 Mbps - Gigabit Ethernet.
IEEE 802.3ad -
Defines link aggregation and trunking.
IEEE 802.4 -
Defines the token-passing bus.
IEEE 802.5 -
Defines the Token Ring access methodology. This standard incorporates IBM's
Token Ring specifications.
IEEE 802.6 -
Defines Metropolitan Area Networks.
IEEE 802.7 - The
broadband technical advisory group.
IEEE 802.8 - The
fiber optics technical advisory group.
IEEE 802.9- Defines
integrated data and voice networks.
IETF (Internet Engineering
Task Force) - a large, open, international community of network
designers, operators, vendors and researchers whose purpose is to coordinate
the operation, management and evolution of the Internet to resolve short- and
mid-range protocol and architectural issues.
IG (Information Group)
- A collection of parameters used to define a specific PNNI function (i.e.,
Nodal Hierarchy, List IG).
Signaling Protocol) - A routing scheme that enables the establishment
of PVCs between ATM switches from different vendors. It uses static, hop-by-hop
routing tables. (Formerly, P-NNI Phase 0)
ILMI (Interim Local
Management Interface) - The standard that specifies the use of the
Simple Network Management Protocol (SNMP) and an ATM management information
base (MIB) to provide network status and configuration information.
Impedance (Z) - The
total opposition by a circuit to the flow of alternating current; a vector sum
of all resistance and reactance in a circuit, expressed in ohms.
Indication Of -
Lights, bells and buzzers indicating that something has or is about to happen.
For example, indication of a camp-on to a station is short bursts of tone
transmitted periodically to a busy phone to indicate that another call is
camped on and waiting.
Inductance - An
electric force field which builds up around a conductor.
Inductor - A coil
of wire, usually wound in a special core of high permeability, which provides
high inductance without necessarily being of high resistance.
Applications do not adjust their demands based on feedback about available
network bandwidth, they run "Open Loop". They are best matched to CBR and VBR
Ingress - One of
two distinctly different roles of the MPC (Multi Protocol Client). As an
Ingress MPC, the client detects sustained flows of packets that are currently
being sent over the routed path to a router that is enabled as an MPS (Multi
ingress - When
referring to a switch, fabric or port, ingress typically refers to the input,
receive or upstream side.
Inhibit - To
prevent a device or circuit from operating.
In Phase - Two or
more alternating currents and/or voltages (at the same frequency) that have
their zero and maximum value occurring simultaneously.
Input - A signal
fed into a circuit.
- Equipment used to put information into or take information out of a computer
Input Transformer -
Transformer at the input to a device which transforms/matches the impedance of
the device to that of the preceding stage.
Inrush Current -
The maximum instantaneous value of the input current to a device when it is
Inside Plant -
Everything inside a telephone company central office.
Insulation - A
material which will not conduct electricity and is suitable for surrounding
conductors to prevent the flow of current.
Insulator - The
glass or ceramic cup attached to a crossarm to which a telephone wire is bound
- Marconi’s implementation of scalable network technology that allows the
network to configure, heal, tune, and protect itself.
- A processor-controlled multiplexer that allocates bandwidth utilization.
- A terminal which contains its own computer, as opposed to a dumb terminal,
which is only a communication device with another computer.
- Companies which sell, install and maintain telephone systems for end users,
Interface - A
demarcation between two devices, where the electrical signals, connectors,
timing and handshaking meet. Often the procedures, codes and protocols that
enable the two devices to interact are included or carried out by the
Interface Data -
the unit of information transferred to/from the upper layer in a single
interaction across a SAP. Each Interface Data Unit (IDU) controls interface
information and may also contain the whole or part of the SDU.
Interface Device -
A device which meets a standard electrical interface on one side and meets some
other non-standard interface on the other.
Interfacing Relay -
A relay used to convert a grounded input alarm to resistance battery, a
grounded input alarm to a loop closure, a grounded input from one plant to
another ground which is compatible with the termination of the alarm, or a
battery input to a grounded output. The relay can also be used to create dry
contacts or spare contacts which will allow a given alarm input to be spread to
Interior - Denotes
that an item (e.g., link, node, or reachable address) is inside of a PNNI
Intermittent Fault -
A defect in a circuit or medium which is not continually apparent.
Internal Reachable Address
- An address of a destination that is directly attached to the logical node
advertising the address.
internet - while an
internet is a network, the term "internet" is usually used to refer to a
collection of networks interconnected with routers.
Internet - (note
the capital "I") the largest internet in the world including large national
backbone nets and many regional and local networks worldwide. The Internet uses
the TCP/IP suite. Networks with only e-mail connectivity are not considered on
Internet Addresses -
The numbers used to identify hosts on an internet network. Internet host
numbers are divided into two parts; the first is the network number and the
second, or local, part is a host number on that particular network.
There are also three
classes of networks in the Internet, based on the number of hosts on a given
Large networks are
classified as Class A, having addresses in the range 1-126 and having a maximum
of 16,387,064 hosts.
Medium networks are
classified as Class B, with addresses in the range 128-191 and with a maximum
of 64,516 hosts.
Small networks are
classified as Class C, having addresses in the range 192-254 with a maximum of
254 hosts. Addresses are given as dotted decimal numbers in the following
In a Class A network,
the first of the numbers is the network number, the last three numbers are the
local host address.
In a Class B network, the first two numbers are the network, the last two are
the local host address.
In a Class C network, the first three numbers are the network address, the last
number is the local host address.
The following table summarizes the classes and sizes:
Network mask values are
used to identify the network portion and the host portion of the address. For:
Class A - the default mask is 255.0.0.0
Class B - the default mask is 255.255.0.0
Class C - the default mask is 255.255.255.0
Subnet masking is used
when a portion of the host ID is used to identify a subnetwork. For example, if
a portion of a Class B network address is used for a subnetwork, the mask could
be set as 255.255.255.0. This would allow the third byte to be used as a
subnetwork address. All hosts on the network would still use the IP address to
get on the Internet.
The ability of software and hardware on multiple machines, from multiple
vendors, to communicate.
Electrical apparatus or equipment that changes DC power to AC power.
Inverter System - A
power system that utilizes inverters to change direct current (DC) to
alternating current (AC) power for powering AC equipment during a power outage
or fluctuation, or where protected AC power is required and commercial power is
Inv. Fail (Inverter Failure)
A discrete alarm notation indicative of an inverter failure considered a major
ION (Internetworking Over
NBMA (Non-Broadcast Multi-Access)) - The Internet Engineering Task
Force (IETF) formed the group which developed the Next Hop Resolution Protocol
IPD (Intelligent Packet
Discard) - A mechanism an ATM switch may use to control data loss in
packet traffic. Any method of cell discard would be considered IPD if cells are
seen as components of higher-layer packets and discarded on that basis in order
to minimize the number of packets affected.
IP (Internet Protocol)
- a connectionless, best-effort packet switching protocol that offers a common
layer over dissimilar networks.
IP Address - A
unique 32-bit integer used to identify a device in an IP network. You will most
commonly see IP addresses written in "dot" notation; for instance,
188.8.131.52 (see IP netmask).
IP Netmask - A
pattern of 32 bits that is combined with an IP address to determine which bits
of an IP address denote the network number and which denote the host number.
Netmasks are useful for sub-dividing IP networks. IP netmasks are written in
"dot" notation; for instance, 255.255.255.0 (see IP address).
IPX Protocol (Internetwork
Packet Exchange) - A NetWare protocol similar to the Xerox Network
Systems (XNS) protocol that provides datagram delivery of messages.
IR Drop - Voltage
drop across a resistance: I (current in amperes) times R (resistance in ohms).
IS (Intermediate system)
- A system that provides forwarding functions or relaying functions or both for
a specific ATM connection. OAM cells may be generated and received.
ISA Bus - A bus
standard developed by IBM for expansion cards in the first IBM PC. The original
bus supported a data path only 8 bits wide. IBM subsequently developed a 16-bit
version for its AT class computers. The 16-bit AT ISA bus supports both 8- and
16-bit cards. The 8-bit bus is commonly called the PC/XT bus, and the 16-bit
bus is called the AT bus.
ISDN (Integrated Services
Digital Network) - A service technology that is offered by many of the
telephone carriers of the world. ISDN combines voice and digital network
services into a single medium or wire.
ISO (International Standards
Organization) - A voluntary, non-treaty organization founded in 1946
that is responsible for creating international standards in many areas,
including computers and communications.
Signals carrying embedded timing information or signals that are dependent on
uniform timing; usually associated with voice and/or video transmission.
which prevents interaction between circuits.
International Telecommunications Union Telecommunications: ITU-T is an
international body of member countries whose task is to define recommendations
and standards relating to the international telecommunications industry. The
fundamental standards for ATM have been defined and published by the ITU-T
IWF (Interworking Function)
- Provides the means for two different technologies to interoperate.
IXC (Interexchange Carriers)
- Long-distance communications companies that provide service between Local
Access Transport Areas (LATAs).