I/O: Input/Output
Input/output, or I/O, is a process or operation that transfers data to or from a computer or a processor. It also refers to the interfaces of different computer units or sub-systems to communicate with each other. Inputs are the signals received by the unit, and outputs are the signals sent from it. The term can also be used as part of an action; to "do I/O" is to perform an input or output operation. Typical I/O devices include printers, hard disk, keyboard and mouse. Some devices are basically input-only devices (keyboard and mouse); others are primarily output-only devices (such as CD) while still others provide both input and output of data (hard disk, diskette, writeable CD-ROMs).

I2P: Invisible Internet Project
Invisible Internet Project, often just called I2P, is a free and open source project building an anonymous and/or pseudonymous virtual private network. The network is a simple layer that applications can use to anonymously and securely send messages to each other.Note that it is likely that there are bugs in the software and there has been insufficient peer review to date.

IAB: Internet Architecture Board
Internet Architecture Board (IAB), a group under the Internet Society (ISOC), is an organization of internetwork researchers who discuss issues pertinent to Internet architecture. IAB is responsible for appointing a variety of Internet-related groups, such as the IETF, IANA, IESG, and IRSG. The IAB is appointed by the trustees of the ISOC.

IAHC: Internet International Ad Hoc Committee
Internet International Ad Hoc Committee (IAHC) is a coalition of participants from the broad Internet community that works to satisfy the requirement for enhancements to the Internet's global DNS. Organizations naming members to the committee include Internet Society (ISOC), Internet Assigned Numbers Authority (IANA), Internet Architecture Board (IAB), Federal Networking Council (FNC), International Telecommunication Union (ITU), International Trademark Association (INTA), and World Intellectual Property Organization (WIPO).

IANA: Internet Assigned Number Authority
Internet Assigned Number Authority (IANA), one of the primary governing bodies for Internet networking, oversees three key aspects of the Internet: top-level domains (TLDs), IP address allocation and port number assignments. Some IANA functions such as IP address allocation are re-assigned to Internet Corporation for Assigned Names and Numbers (ICANN).

IBC: In-band Control
In-band Control(IBC) refers to issuing control commands on the data channel. In-band commands are passed by setting an in-band-command bit in the data buffer.

IBM Director
IBM Director is an element management system (EMS) or workgroup management system (WMS). The software was originally written to run on OS/2 2.0. It has subsequently gone through a number of name changes in the interim. It was changed in 1996 to IBM PC SystemView. Later that same year, it was renamed to TME 10 NetFinity. The following year, it reverted back to a slightly altered version of its original name: IBM Netfinity Manager.

IBTA: InfiniBand Trade Association
InfiniBand Trade Association (IBTA) is an industry group that developed and published the specification for the InfiniBand architecture. The development of this specification had industry-wide support, with over 200 worldwide companies participating.

ICANN: Internet Corporation for Assigned Names and Numbers
Internet Corporation for Assigned Names and Numbers (ICANN) is non-profit, private corporation that assumed responsibility for IP address space allocation, protocol parameter assignment, domain name system management, and root server system management functions that formerly were performed under U.S. Government contract by IANA and other entities.

ICD: International Code Designator
International Code Designator (ICD) is one of two ATM address formats developed by the ATM Forum for use by private networks. It is adapted from the subnetwork model of addressing in which the ATM layer is responsible for mapping network layer addresses to ATM addresses.

ICP Cell: IMA control protocol cell
Inverse multiplexing over ATM (IMA) control protocol cell (ICP Cell), a feature in the IMA, is used for aligning the cells in multiple links. A receiving interface uses ICP cells to determine the differential delay between the links in the IMA group. ICP cells are sent on each link once per IMA frame. By default, each frame consists of 128 cells. The ICP cell can be located anywhere inside the frame (cell position 0 or cell position 127 or any cell position in between).

ICPIF: Calculated Planning Impairment Factor loss/delay busyout threshold
Calculated Planning Impairment Factor loss/delay busyout threshold (ICPIF) is an ITU-T G.113 standard for measuring quality of service. ICPIF replaces the old QDU (Quantisation Distortion Units) which were a subjective measurement. ICPIF represents predefined combinations of loss and delay in a VOIP network call. Packet loss and delay determine the threshold for initiating the busyout state. Gateways generate ICPIF values for each VoIP call and these calculations can be stored for each VoIP call record.

ICR: Initial Cell Rate
Initial Cell Rate (ICR) is an ATM Available Bit Rate (ABR) service parameter, in cells/sec, that is the rate at which a source should send initially or after an idle period.

ICS: Internet Connection Sharing
Internet Connection Sharing (ICS), a featuer in Microsost Windows, allows a local network of Windows computers to share a single Internet connection. ICS follows a client/server model. To set up ICS, one computer must be chosen as the server. The designated computer must support two network interfaces, one directly connected to the Internet and the other connected to the remainder of the LAN. In a traditional home dial-up network, for example, the server computer is directly connected to the modem.

I-D: Internet-Draft
Internet-Drafts (I-Ds) are the working documents of the IETF from its Areas and Working Groups. They are valid for a maximum of six months and might be updated, replaced, or made obsolete by other documents at any time. Very often, I-Ds are precursors to RFCs.

IDB: Interface Description Block
Interface Description Block (IDB) is a sub-block area of memory that is private to an application. This area stores private information and states variables that an application wants to associate with an IDB or an interface. The application uses the IDB to register a pointer to its sub-block, not to the contents of the sub-block itself.

IDI: Initial Domain Identifier
Initial Domain Identifier (IDI) is a portion of an NSAP or NSAP-format ATM address that specifies the address allocation and the administration authority.

IDN: International Data Number
International Data Number (IDN) is a field in the X.121, which is the ITU-T address format of the X.25 protocol suite used as part of call setup to establish a switched virtual circuit between Public Data Networks (PDNs), connecting two network user addresses (NUAs). IDN consists of two fields: the Data Network Identification Code (DNIC) and the National Terminal Number (NTN). DNIC is an optional field that identifies the exact PSN in which the destination DTE device is located. The DNIC has two subfields: Country and PSN. The Country subfield specifies the country in which the destination PSN is located. The PSN field specifies the exact PSN in which the destination DTE device is located. The NTN identifies the exact DTE device in the PSN for which a packet is destined. This field varies in length.

IDP: Initial Domain Part
Initial Domain Part (IDP) is a part of a Connectionless Network Service (CLNS) address that contains an authority and format identifier and a domain identifier.

IE: Internet Explorer
Internet Explorer (IE) is a free Web browser by Microsoft. Internet Explorer is typically pre-installed on all Windows-based computers. Microsoft Internet Explorer contains various Internet connections, network file sharings and security settings. Among other features, Internet Explorer supports: (1）proxy server configuration ；(2）auto-dialing a dialup Internet connection ；(3）FTP client capabilities ；(4）remote LAN administration

IEC 62365
IEC 62365 is a standard published by the International Electrotechnical Commission that specifies a method for packing AES3 professional digital audio streams over Asynchronous Transfer Mode newtorks. This is an identical method to that published by the Audio Engineering Society as AES47.

IEC: International Electrotechnical Commission
International Electrotechnical Commission (IEC) is an industry group that that prepares and publishes international standards for all electrical, electronic and related technologies. These serve as a basis for national standardization and as references when drafting international tenders and contracts.

IEEE 1284
IEEE 1284 is a standard that defines bi-directional parallel communications between computers and other devices. IEEE 1284 is widely used as the interface for the communications between the computer and the printer parallel port.

IEEE 488
IEEE-488, now 488.1, is a communication bus standard that allows up to 15 devices to share a single bus by daisy-chaining, with the slowest device participating in the control and data transfer handshakes to determine the speed of the transaction. The maximum data rate is about one megabyte per second. IEEE-488 is based on the Hewlett-Packard Instrument Bus (HP-IB).

IEEE: Institute of Electrical and Electronics Engineers
Institute of Electrical and Electronics Engineers (IEEE) is a professional organization and standards body.

IEPG: Internet Engineering Planning Group
Internet Engineering Planning Group (IEPG) is an informal group primarily composed of Internet service operators. Its goal is to promote a globally coordinated Internet operating environment.

IESG: Internet Engineering Steering Group
Internet Engineering Steering Group (IESG) is an organization appointed by the Internet Architecture Baord (IAB) that manages the operation of the IETF.

IETF: Internet Engineering Task Force
Internet Engineering Task Force (IETF) is the task force consisting of numerous working groups responsible for developing Internet standards in the format of Request For Comments (RFCs). The IETF operates under the auspices of the Internet Architecture Board (IAB) and the Internet Society (ISOC).

IFIP: International Federation for Information Processing
International Federation for Information Processing (IFIP) is a research organization that performs OSI prestandardization work. Among other accomplishments, IFIP formalized the original Message Handling System (MHS) model.

IF-MIB: Interfaces Group MIB
Interfaces Group MIB (IF-MIB) is a portion of the Management Information Base (MIB) for use with network management protocols such as the Simple Network Management Protocol (SNMP).

I-frame: Information frame
Information frame (I-frame) is one of three SDLC frame formats. The other two frames are supervisory, and unnumbered. Information frames transport sequenced user data between the local and remote stations.

IFRAME: Inline frames
Inline frames (IFRAME) is one type of the HTML frames which allow authors to present documents in multiple views, which may be independent windows or subwindows. The IFRAME element defines an inline frame for the inclusion of external objects including other HTML documents. IFRAME provides a subset of the functionality of OBJECT; the only advantage to IFRAME is that an inline frame can act as a target for other links.

IIH: IS-IS Hello
IS-IS Hello (IIH) is a message sent by all IS-IS systems to maintain adjacencies.

IINREN: Interagency Interim National Research and Education Network
Interagency Interim National Research and Education Network (IINREN) is the former network of the National Research and Education Network (NREN).

IIS: Internet Information Services
Internet Information Service (IIS), also known as Internet Information Server, is a Microsoft developed system that provides a set of Internet-based services for servers using Microsoft Windows. It is the world's second most popular web server in terms of overall websites behind the Apache HTTP Server although the gap is decreasing. IIS currently supports FTP, SMTP, NNTP and HTTP/HTTPS.

IITA: Information Infrastructure Technology and Applications
Information Infrastructure Technology and Applications (IITA) is a component of the High Performance Computing and Communications (HPCC) program intended to ensure U.S. leadership in the development of advanced information technologies.

ILMI: Interim Local Management Interface
Interim Local Management Interface (ILMI) is an interim specification used to provide network management functions between end users and networks and between private and public networks in an ATM network. ILMI allows bi-direction exchange of management information between UNI Management Entities (UMEs) within UNI peers. Management information related to the Physical Layer, ATM Layer, Virtual Path Connections, Virtual Channel Connections, Address Registration, as well as ATM Layer Statistics, is represented in a standard MIB structure called the ATM UNI ILMI MIB.

IMA Group
Inverse multiplexing over ATM (IMA) Group is a collection of physical links grouped to form a higher-bandwidth logical link and assigned to an ATM port. The rate of the IMA group is approximately the sum of the individual link rates.

IMHO: In My Humble Opinion
IMHO - "In My Humble Opinion", is one of many short-form phrases seen in e-mail messages, newsgroups, and so on.

Immediate Start
Immediate Start is a method of E&M (ear & mouth) signaling. When the signaling leads indicate a change to an off-hook state, the interface is immediately ready to send signaling information.

IMP: Interface Message Processor
Interface Message Processor (IMP) is the old name for ARPANET packet switches.

In-Rate Cell
In-Rate cell is a tybe of ATM ABR cell sent with CLP=0. ABR RM-cells shall be sent with CLP=0 except in certain circumstances. All other ABR cells shall be sent with CLP=0.

INA: Information Networking Architecture
Information Networking Architecture (INA) is the Bellcore object-oriented architecture for the management of ATM and SONET equipment and services in an operating company environment.

INA: Interactive Network Adapter
Interactive Network Adapter (INA) is the headend unit controlling the bidirectional broadband data communications over the hybrid fiber-coaxial (HFC) network to the customer premises equipment (CPE) that is connected to the HFC network. Every transmission in a broadband network has to go through the INA at a head-end which is the control center for a cable system where video, audio, and data signals are processed and distributed along the coaxial cable network.

INASoft
INASoft is the system for the management of ATM and SONET equipment and services in an operating company environment by Bellcore based on the Information Networking Architecture (INA).

INB: Install Busy
Install Busy (INB) is a status of operatipon in many systems. For example, INB may indicate a maintenance operation of the signaling channel during which, apart from this channel not being available for signaling, the configuration parameters (mostly ds0 characteristics of this interface) can be changed. The implementor may chose to just use the busy state as a superset state instead of inB in which case this state will be rendered redundant.

Inband Signalling
Inband (In-Band) Signalling, also known as robbed-bit signalling, is a type of signalling in which metadata and control information is sent in the same channel used for data. For example, a line uses 8 kbps of each 64 kbps channel for WAN synchronization and signalling. The remaining 56 kbps handle the transmission of user data. T1 access lines containing one or more switched channels, and Switched-56 lines use inband signalling.

INE: Intelligent Network Element
Intelligent Network Element (INE) is network element that can be provisioned from a remote OSS.

Inetd: Internet Daemon
Internet Daemon (Inetd) is an application that controls smaller internet services like telnet, ftp, and POP.

InfiniBand
InfiniBand, developed by InfiniBand Trade Association (IBTA), is an I/O architecture and a specification for the transmission of data between processors and I/O devices. Instead of sending data in parallel, which is what PCI does, InfiniBand sends data in serial and can carry multiple channels of data at the same time in a multiplexing signal. InfiniBand Technology, replacing PCI, will be used to connect servers with remote storage and networking devices, and other servers. It will also be used inside servers for inter-processor communication (IPC) in parallel clusters.

Information Element
Information Element, a term used in ATM networking, is the portion of a signaling packet that carries information, such as addresses, used in the UNI specification.

Infranet Initiative
The Infranet Initiative is driven by Juniper Networks to develop a high-performance universal public network that would serve as a supplement to the Internet for businesses and other high-demand users. The proposed network, called the infranet, would provide guaranteed security, reliability, and quality of service (QoS) for applications that are too demanding to run reliably over the Internet, such as utility computing, multi-provider VPNs, and inter-enterprise peer-to-peer collaboration.

Ingress Noise
Ingress noise, a common type of noise found on HFC cable networks, occurs at a single spectral frequency. Common sources of this type of noise include CB (citizen band) radios and other communications devices. The fact that the noise is limited to specific frequencies enables it to be cancelled using an ICF (ingress cancellation filter).

INOC: Internet Network Operations Center
Internet Network Operations Center (INOC) is a group that in the early days of the Internet monitored and controlled the Internet core gateways (routers). INOC no longer exists.

Insured Burst
Insured Burst, a term used in the ATM or Frame Relay network, is the largest burst of data above the insured rate that will be temporarily allowed on a PVC and not tagged by the traffic policing function for dropping in the case of network congestion. The insured burst is specified in bytes or cells.

Insured Rate
Insured Rate is the committed data throughput of ATM PVC, in bits or cells per second, that an ATM network of service provider supports under normal network conditions. The insured rate is 100 percent allocated; the entire amount is deducted from the total trunk bandwidth along the path of the circuit.

Insured Traffic
Insured Traffic is the traffic within the insured rate specified for an ATM PVC. This traffic should not be dropped by the network under normal network conditions.

INTAP: Interoperability Technology Association for Information Processing
Interoperability Technology Association for Information Processing (INTAP) is a technical organization of Japan. INTAP conducts and promotes R&D, surveys, and publicity activities for promoting interoperability of information processing technologies.

Integrated Services Internet
Integrated Services Internet, also known IntServ, is an IETF proposed architecture for enhancing IP to allow it to support integrated or multimedia services, including traffic management, especially QoS, mechanisms. The Resource ReSerVation Protocol (RSVP) is a key protocol in such architecture.

Intelligent network
An intelligent network is a computer network in which the network is in control of application creation and operation. Relatively dumb terminal and devices on the network periphery access centralized network services on behalf of their users. The owners of the network are in complete charge of the type and quantity of applications that exist on the network. This Intelligent neowrk should not be confused with the Intelligent Network in Telecom which provides featured call services such as call waiting, forwarding etc.

Interarea Routing
Interarea (or Inter-Area) Routing refers to routing between two or more logical areas. Routing Information Protocol (RIP) is an often used routing protocol for the inter-area routing.

Interior router
Interior router is a type of router that routers within the autonomous system and is expected to communicate only with routers on networks within the autonomous system.

International Standards Organization
International Standards Organization is often the erroneous expansion of the acronym ISO. The accurate expansion of ISO is: International Organization for Standardization.

Internet
Internet, a term originally coined in the 1970s, refers to the global network of public computers based on the Internet Protocol (IP). The Internet supports the public WWW and many special-purpose client/server software systems. Internet connects many private corporate intranets and private home LANs. Over the past decades, a number of smaller national networks like ARPANET, BITNET, CSNET, and NSFNET evolved, merged, or dissolved, then finally joined with non-US networks to form the global Internet.

Internet Backbone
The Internet backbone refers to the main 'trunk' connections of the Internet. It is made up of a large collection of interconnected commercial, government, academic and other high-capacity data routes and routers that carry data across the countries, continents and oceans of the world.

Internet Café
An Internet cafe or cybercafe is a place where one can use a computer with Internet access for a fee, usually per hour or minute; sometimes one can have unmetered accesses with a pass for a day or month, etc. It may or may not serve as a regular cafe as well, with food and drinks being served.

Internet Oracle
The Internet Oracle (historically known as The Usenet Oracle) is a collaborative effort at collective humor in a pseudo-Socratic question-and-answer format. A user sends a question to the Oracle via e-mail or the Internet Oracle website, and it is randomly sent to another user who has asked a question. This second user may then answer the question (or not; if it is not answered within 24 hours it is put back into the queue to be given to another user to answer). Meanwhile, the original questioner is also sent a question which he/she may choose to answer. All exchanges are conducted through a central distribution system which also makes all users anonymous.

Internet Telephony
Internet Telephony is a generic term used to describe various technologies to provide voice telephony services over the Internet.

Internet Troll
Internet troll refers to a person who posts inflammatory messages on the internet, such as on online discussion forums, to disrupt the discussion or to upset its participants. The word, or its variant, "trolling", is also used to describe such messages or the act of posting them.

Internet2
Internet2, formerly called UCAID (University Corporation for Advanced Internet Development), is a non-profit consortium which develops and deploys advanced network applications and technologies, mostly for high-speed data transfer. It is led by 207 US universities and partners from the networking and technology vendors. Some of the technologies it has developed include IPv6, IP multicasting and quality of service.

Internetwork
Internetwork generally refers to a collection of networks interconnected by routers and other devices that function as a single network. Internetwork sometimes is called an internet, which should not be confused with the Internet.

Internetworking
Internetworking basically refers to the industry devoted to connecting networks together, which may include products, services, procedures, and technologies.

InterNIC: Internet Information Center
InterNIC, full named Internet Information Center, is an organization under the Internet Corporation for Assigned Names and Numbers (ICANN) that serves the Internet community by supplying user assistance, documentation, Whois, registration service for Internet domain names, and other services.

Interop
Interop, formerlly called Network and Inerop or N+I, is a major conference and technology exposition in the networking industry, organized by CMP Media.

Interoperability
Interoperability describes the situation that devices and services from multiple vendors are compatible with each other, and can be integrated into a generic network containing a wide range of vendor products. Interoperability is a significant factor among networking considerations. The technical elements of interoperability may include a bundle of protocols and a flexible architecture to accommodate upgrades.

Intra-area Routing
Intra-area Routing refers to routing within a logical area when the source and destination are in the same area. Border Gateway Protocol (BGP) is an often used protocol for the Intra-area rouing.

Intranet
An intranet is a network used internally in an organization to facilitate communication and access to information that is sometimes access-restricted. An intranet typically is based on the same TCP/IP, client and server, and web technologies that are used for the Internet. An Intranet may be only on a Local Area Netowrk (LAN), or it may connect a few corporate sites through a Wide Area Network, or the Internet.

IntServ: Integrated Service
Integrated Services (IntServ), also known as Integrated Services Internet, is an architecture, which specifies the elements to guarantee quality of service (QoS) on networks. IntServ can for example be used to allow video and sound to reach the receiver without interruption. IntServ specifies a fine-grained QoS system, which is often contrasted with DiffServ's coarse-grained control system. The idea of IntServ is that every router in the system implements IntServ, and every application that requires some kind of guarantees has to make an individual reservation. "Flow Specs" describe what the reservation is for, while "RSVP" is the underlying mechanism to signal it across the network.

IONL: Internal Organization of the Network Layer
Internal Organization of the Network Layer (IONL) is an OSI framework as defined in ISO8648 for the detailed architecture of the network layer. Basically, it partitions the network layer into subnetworks interconnected by convergence protocols (equivalent to internet working protocols), creating what the Internet community calls a catenet or an internet.

IOS: Internetwork Operating System
Internetwork Operating System (IOS) is the operating system used on Cisco Systems routers and some network switches (those which do not use CatOS). It is a multitasking operating system and provides kernel services such as process scheduling as well as the command line interface and routing software.

IP address
IP address is an identity of a computer or other network device on a TCP/IP network. Networks using the TCP/IP protocol route packets based on the IP address to its destination. For the most TCP/IP networks which are based on the IPv4, the format of an IP address is a 32-bit numeric address written as four numbers separated by periods. IPv6 uses 128-bit binary for addressing purpose. IPv6 addresses are expressed in hexadecimal format (base 16) which allows not only numerals (0-9) but a few characters as well (a-f).

IP Datagram
IP Datagram, also known as IP packet, is a unit of information passed across the IP-based network such as the Internet. It contains source and destination addresses along with data and a number of fields that define such things as the length of the datagram, the header checksum, and flags to indicate whether the datagram can be (or was) fragmented.

IP Explicit Path
IP Explicit Path is a list of IP addresses, each representing a node or a link in the explicit path. Explicit path is a pre-defined route or path by the message originator for a message to travel from the sender to the receiver.

IP Multicast
IP Multicast is a routing technique that allows IP traffic to be propagated from one source to a number of destinations or from many sources to many destinations. In the case of multicasting, one packet is sent to a multicast group identified by a single IP destination group address.

IP Multicast Heartbeat
The IP multicast heartbeat is a feature in many routers that enables user to monitor the delivery of IP multicast packets and to be alerted if the delivery fails to meet certain parameters.

IP over ATM
IP over ATM refers to providing IP services above the layer 2 ATM network. There are a few technologies to make this happen, for example, Classic IP over ATM (CIM) or using MPOA (Multiprotocol over ATM) etc.

IP Precedence
IP Precedence is a 3-bit value in the type of service (TOS) byte of IP header used for assigning precedence to IP packets. IP Precedence provides the ability to classify network packets at Layer 3, analogous to the functionality of the 802.1P protocol at Layer 2. With IP Precedence configured, network packets traverse IP Precedence devices according to the priority you set. Priority traffic is always serviced before traditional traffic.

IP Router
An IP router is a computer networking device that forwards data packets across an internetwork toward their destinations using the Internet Protocol (IP). Routing occurs at layer 3 (the Network layer) of the OSI seven-layer model and IP is the layer 3 protocol in the TCP/IP protocol suite.

IP Subnetting
IP Subnetting refers to dividing an IP network into a few sub networks (subnet). Subnetting an IP Network can be done for a variety of reasons, including organization, use of different physical media (such as Ethernet, FDDI, WAN, etc.), preservation of address space, and security. The most common reason is to control network traffic. A router is used to connect IP subnets to minimize the amount of traffic each segment must receive. IP networks are divided using a subnet mask which defines the boundaries of an IP subnet. Applying a subnet mask to an IP address allows you to identify the network and node parts of the address.

IP Switch
IP Switch is a device that forwards packets based solely upon destination IP addresses. The device does not necessarily speak any IP routing protocol(s) and does not perform routing or routing calculations. It learns the IP addresses of the attached devices by examining the IP source addresses. The goal is to switch IP packets faster than traditional router-based layer 3 forwarding.

IP Telephony
IP Telephony, also known as Voice over IP (VOIP), refers to transmission of voice and fax phone calls over data network that uses the Internet Protocol (IP).

IP Traceback
IP Traceback refers to any method for reliably determining the origin of a packet on the Internet. The datagram nature of the Internet makes it difficult to determine the originating host of a packet C the source id supplied in an IP packet can be falsified (IP spoofing). IP Traceback is a critical ability for identifying sources of attacks and instituting protection measures for the Internet.

IPAM: IP Address Management
IP Addresses Management (IPAM) refers to the system, which allows the allocation, classification, and tracking of IP addresses. IPAM systems provide services such as immediate access to information --which IP addresses are in use; when they were allocated; which devices they were assigned to; who is using them -- which is critical to eliminating conflicts and network outages, tracking critical assets, ensuring network security, troubleshooting network problems and enabling regulatory compliance. IP address management also lets customers manage DNS and IP address data at company-wide level, delivering unified management, monitoring, and administration, and providing for appropriate levels of centralized auditing and reporting.

IPC: Interprocess communications
Interprocess communications (IPC) are mechanisms that facilitate communication between processes. IPC makes it possible to create large systems that are complex in function, yet simple and streamlined in design.

IPCheck
IPCheck, also known as IPCheck Server Monitor, is an uptime and downtime network monitoring software for Microsoft Windows.

IPng : IP Next Generation
IP Next Generation(IPng) refers to the efforts of the Internet Engineering Task Force (IETF) to define a new version of the Internet Protocol (IP), IPv6, to handle larger IP addresses. Therefore, IPng actually refers to IPv6.

IPTV: Internet Protocol Television
Internet Protocol Television (IPTV) is a service for the delivery of broadcast TV, movies on demand and other interactive multimedia services over a secure, end-to-end operator managed broadband IP data network with desired QOS to the public with a broadband Internet connection. IPTV system may also include Internet services such as Web access and VOIP where it may be called Triple Play and is typically supplied by a broadband operator using the same infrastructure. IPTV is not the Internet Video that simply allows users to watch videos, like movie previews and web-cams, over the Internet in a best effort fashion. IPTV technology offers revenue-generating opportunities for the telecom service providers.

IR: Intermediate Reach
Intermediate Reach(IR) refers to the distance specification for optical systems that operate effectively from 3 to 20 km (1.8 to 12.5 mi).

IR: Internet Registry
Internet Registry(IR) is an organization that is delegated the responsibility of network address and autonomuous system identifiers from the Internet Assigned Numbers Authority (IANA), which has the discretionary authority to delegate portions of its responsibility.

IRB: Integrated Routing and Bridging
Integrated Routing and Bridging (IRB) is a feature in routers that enables routing of a given protocol between routed interfaces and bridge groups within a single switch router. In other words, it enables routers acting somewhat like switches. IRB also allows multiple router interfaces to be in a common Virtual Local Area Network (VLAN), with routing between such VLAN's.

IRN: Intermediate Routing Node
Intermediate Routing Node (IRN), a concept in the IBM SNA network, is a subarea node with an intermediate routing capability.

IRR: Information request
Information request (IRR) is a Registration, Admission, and Status protocol (RAS) message in the H.323 VOIP network that enables Gatekeepers to maintain call accounting information by reporting the call-connection time of connected calls to the Gatekeeper.

IRSG: Internet Research Steering Group
Internet Research Steering Group(IRSF) is a sterring committee under the Internet Architecture Board (IAB) to define research directions of the Internet Research Task Force (IRTF).

IRTF: Internet Research Task Force
Internet Research Task Force (IRTF) is a community of network experts that considers Internet-related research topics. The IRTF is governed by the Internet Research Steering Group (IRSG) under the Internet Architecture Board (IAB). The mission of IRTF is to promote research of importance to the evolution of the future Internet by creating focused, long-term and small Research Groups working on topics related to Internet protocols, applications, architecture and technology.

IS: Intermediate System
Intermediate System (IS) is a routing node in an OSI network which performs network layer forwarding similar to an IP router in the TCP/IP network. The protocol used by the the IS is Intermediate System to Intermediate System (IS-IS) routing protocol.

ISA: Industry-Standard Architecture
Industry-Standard Architecture (ISA) is a 16-bit bus technology used for for IBM compatible personal computers (PC). ISA is now mostly succeeded by Intel's 32-bit Peripheral Component Interconnect (PCI) bus technology.

Isarithmic Flow Control
Isarithmic Flow Control is a flow control technique that permits travel through the network. Isarithmic flow control is not commonly implemented.

ISDN BRI
An ISDN Basic Rate Interface (ISDN BRI) is a type of ISDN interfaces that uses two B channels for user data, and one 16-kbps D channel for ISDN D-channel signalling. Both B channels can be switched, both channels can be nailed up, or one channel can be switched and the other nailed up. BRI stands for Basic Rate Interface. A line of this type can connect to standard voice service, Switched-56 data service, or Switched-64 data service.

ISDN D-channel Signalling
ISDN D-channel Signalling is a type of out-of-band signalling in which a D channel handles WAN synchronization and signalling, and the B channels carry the user data. T1 PRI, E1 PRI, and ISDN BRI lines use ISDN D-channel signalling.

ISO 3309
ISO 3309 defines the HDLC procedures by ISO, in which ISO 3309:1979 specifies the HDLC frame structure for use in synchronous environments and ISO 3309:1984 specifies proposed modifications to allow the use of HDLC in asynchronous environments as well.

ISO 9000
ISO 9000 is a set of international quality-management standards defined by ISO. The standards, which are not specific to any country, industry, or product, allow companies to demonstrate that they have specific processes in place to maintain an efficient quality system.

ISO Protocols
ISO Protocols are a group of protocols defned by the nternational Organization for Standardization (ISO based on the Open Systems Interconnection (OSI) model. The OSI model defines the communications process into 7 layers, dividing the tasks involved in moving information between networked computers into seven smaller, more manageable task groups.

ISO: International Organization for Standardization
International Organization for Standardization (ISO) is an international organization that is responsible for a wide range of standards, including those relevant to networking. ISO developed the OSI reference model, a popular networking reference model.

ISOC: Internet Society
Internet Society (ISOC) is an international nonprofit organization, founded in 1992, that coordinates the evolution and use of the Internet. In addition, ISOC delegates authority to other groups related to the Internet, such as the Internet Architecture Board (IAB).

ISODE: ISO Development Environment
ISO Development Environment (ISODE) is a large set of libraries and utilities used to develop upper-layer OSI protocols and applications from transport layer to application layer. ISODE formed the basis for popular implementations of directory and email services X.400 and X.500. Implementations of FTAM and VT were included in ISODE, and implementations of X.400 P7 (PPMS), TMN (OSIMIS) and other OSI protocols were also made atop ISODE.

ISP: Internet Service Provider
An Internet Service Provider (ISP) is a company that provides Internet connectivity services to home and business customers. ISPs support one or more forms of Internet access, including modem dial-up, DSL access, cable modem broadband service, dedicated T1/T3 lines and wireless access.

ISR: Intermediate Session Routing
Intermediate Session Routing (ISR) is an initial routing algorithm used in the IBM APPN. ISR provides node-to-node connection-oriented routing. Network outages cause sessions to fail because ISR cannot provide nondisruptive rerouting around a failure. ISR has been replaced by High Performance Routing (HPR).

ISSI: Inter-Switching System Interface
Inter-Switching System Interface (ISSI) is a standard interface between Switched Multimegabit Data Service (SMDS) switches.

ITCM: Integrated Telephony Cable Modem
Integrated Telephony Cable Modem (ITCM) is a DOCSIS compliant cable modem that enables subscriber VoIP services.

Itnet: Institute of Technology Network
Institute of Technology Network (ITnet) is a Packet over SONET (PoS) based multi Mbits network created for the Institutes of Technology in the Republic of Ireland. ITnet uses a 45 Mbit/s link to each of the institutions and an international link of 310 Mbit/s via HEAnet.

ITT: Ideal Transmission Time
Ideal Transmission Time (ITT) is the transmission time for ATM Available Bit Rate (ABR) CLP=0 cells, if the difference between itself and the transmission time for the previous CLP=0 cell on the connection is greater than or equal to the minimum: (a) the inverse of the ACR in effect immediately after the transmission time of the first of the two cells; (b) the inverse of the ACR in effect immediately before the transmission time of the second of the two cells. The transmission time for the first cell on the connection is automatically an ITT.

ITU: International Telecommunication Union
International Telecommunication Union (ITU) is an organization established by the United Nations to set international telecommunications standards and to allocate frequencies for specific uses.

ITU-T: International Telecommunication Union Telecommunication Standardization Sector
International Telecommunication Union Telecommunication Standardization Sector (ITU-T) is an international body under the International Telecommunication Union (ITU) that develops worldwide standards for telecommunications technologies. The ITU-T carries out the functions of the former CCITT.

IXP: Internet Exchange Point
An Internet Exchange Point (IXP) is a physical infrastructure that allows different Internet Service Providers (ISPs) to exchange Internet traffic between their autonomous systems by means of mutual peering agreements. IXPs are typically used by ISPs to reduce dependency on their respective upstream providers; furthermore, they are used to increase efficiency and fault-tolerance.