Internet Engineering Task Force
Internet group management protocol
An emerging technology, IMS is a next-generation networking (NGN) architecture for telecom operators launching mobile and fixed multimedia services and merges the internet with the mobile world. Its aim is to provide all the services, current and future, that the internet provides. In this way, IMS offers telcos and service providers the ability to control and charge for individual services irrespective of a user’s location, access technology or device. Users are able to execute all their services when roaming, as well as from their home networks. IMS uses a voice over IP (VoIP) implementation based on a 3GPP (third generation partnership project) standardised implementation of SIP. It operates using standard internet protocol (IP) and supports both packet-switched and circuit-switched communications. It is envisaged that IMS will eventually work with any network (fixed, mobile or wireless) with packet-switching functions, such as GPRS, UMTS, CDMA2000, WLAN, Wimax, DSL and cable. Older circuit-switched phone systems (POTS, GSM) are supported through gateways. Open interfaces between control and service layers allow elements and calls/sessions from different access networks to be mixed. IMS should eventually make it easier to offer just about any IP-based service.
International Mobile Telecommunications 2000
Intelligent network: a network that is controlled by a separate network of computers and allows functionality to be distributed flexibly at a variety of nodes. The IN enables operators to offer enhanced facilities such as freephone, premium rate information services, and call distribution services.
The name given to the indigenous wireline telecoms network operator/services provider that operated or currently operates as a government-controlled monopoly. Following deregulation and privatisation, the incumbent operators commonly undertakes to operate, maintain and improve their respective national telecoms network, but are required to enter into interconnection agreements and share access with other independent national/regional telcos and local exchange carriers. In the US, an incumbent local exchange carrier (ILEC) is a telephone company that was providing local service when the Telecommunications Act of 1996 was enacted. ILECs include the former Bell operating companies which were grouped into holding companies known as the regional Bell operating companies (RBOCs) when the Bell system was broken up.
The entrance to a network.
Interactive game
Computer and video game in which the choices, actions and decisions of the user influence how the game unfolds.
Inter-carrier compensation
As defined by the FCC (US), this term “refers to the charges that one carrier pays to another carrier to originate, transport, and/or terminate telecommunications traffic”. There are two major forms of inter-carrier compensation – access charges and reciprocal compensation. 
Interconnect billing
Managing and settlement of interconnection agreements between network operators to provide national and global service coverage becomes more and more complex with the advent of new technologies, services and partnerships. Interconnect billing solutions take the form of an integrated hardware and software package that can be designed so that incumbent carriers and new entrants may identify and maintain the various interconnect fees, discounting agreements and billing for many different types of services using the same platform: traditional voice – origination, termination and transit; mobile – roaming voice, SMS and data; ISPs’ data traffic (broadband) and content aggregation and delivery. Advanced billing engines may offer comprehensive management reports and analysis in such areas as mediation, aggregation, rating and location of revenue leakage.
The connection of separate pieces of equipment or transmission facilities within, between or among telecoms networks.
Interconnection agreement
An agreement between carriers that provides for interconnection, co location, resale, network elements, and ancillary services between the parties.
Interconnection point
The physical point on the network that is the demarcation point between ownership of the transmission facility and the outside network.
Interlata service
Telecoms between a point located in a local access and transport area (Lata) and a point located externally.
Interoffice trunk
Trunk circuit connecting two local telcos’ central offices (see CO).
Intralata service
Telecoms services that originate and end within one local access and transport area (Lata).
Interoffice facility: provides routing for CLECs by using multiple interoffice transmission paths over non-dedicated facilities.
Internet protocol
Internet protocol multi-protocol label switching: Commonly referred to as MPLS, this technology integrates Layer 2 information about network links (bandwidth, latency, utilisation) into Layer 3 (IP) within a particular autonomous                 system (eg ISP) in order to simplify and improve IP-packet exchange. It offers network operators the flexibility to divert and route traffic around link failures, congestion, and bottlenecks. When packets enter an MPLS-based network, label edge routers (LERs) give them a label (identifier). These labels contain information based on the routing table entry (ie destination, bandwidth, delay, and other metrics), and refer to the IP header field (source IP address), Layer 4 socket number information, and differentiated service. Once this classification is complete and mapped, different packets are assigned to corresponding labelled switch paths (LSPs), where label switch routers (LSRs) place outgoing labels on the packets. The LSPs enable network operators to divert and route traffic based on data-stream type.
IP on demand
An auction process that allows IP transit buyers to purchase bandwidth as and when required.
IP transit
Wholesale internet bandwidth sold to ISPs and content providers, whereby pricing is typically offered on a “per Mbps per month” basis and requires the purchaser to commit to a minimum volume of bandwidth.
Internet protocol virtual private network
International private leased circuit
Internet protocol television: provision of programming via a video stream encoded as a series of IP packets, IPTV can be free or fee-based and embraces the delivery of either live TV or stored video. Furthermore, it can be    bundled with other IP services, including VoIP and high-speed internet access. IPTV sends only one programme at a time. Content remains on the service provider’s network and only the selected programme is sent to the home. IPTV primarily uses multicasting with internet group management protocol (IGMP) version 2 for live television broadcasts and real time streaming protocol for on-demand programmes.
IP Exchange: provides a next-generation backbone network for all commercial IP traffic with governance authority, whereby end-to-end SLAs are established between dual carriers/operators using standardised QoS attributes and controlled round-trip delay (RTD), jitter and packet-loss tables. Under development by the GSM Association, the IPX is a “hubbing” model that will be open to all GSM, CDMA and Wifi operators, and enable the provision of multiple services and secure application and content distribution.
Indefeasible rights of use: the owner of the IRU has the right to use the circuit for the time and bandwidth the IRU applies to.
Integrated services digital networks
Internet service provider
International Telecommunications Union
ITU settlements
The ITU’s international standard for interconnect billing, whereby the traffic originator reports traffic to all transiting and terminating operators. This process is applied when two network operators have direct or indirect access to each other. Traffic is measured and then priced according to their agreement negotiated within this ITU framework.
International Telecommunications Union – Telecommunication Standardisation Sector: responsible for studying technical, operating, and tariff issues and making recommendations on these.
Interexchange carrier or interexchange common carrier: Provides interlata or intralata long-distance telephone services.
IXC mileage
Inter-exchange mileage: the airline mileage between two cities.