Active Member PC 2 Phone Member that has paid to or got paid by PC 2 Phone for the past traffic exchange at least once.

AHT (Average Hold Time) The average length of time between the moment a caller finishes dialing and the moment the call is answered or terminated.

AS (Autonomous System) A set of routers under a single technical administration. An AS uses an internal gateway protocol and common metrics to route Packets within the AS, and uses an external gateway protocol to route packets to other ASs.

ASP (Application Service Provider) An independent, third-party provider of software-based services delivered to customers across a wide area network (WAN).

ASR (Answer-Seizure Ratio) The ratio of successfully connected calls to attempted calls (also called 'Call Completion Rate'). ASRs vary by routes. A typical ASR to Pakistan is lower than that of Germany. Reasons for this include the quality of the network and the fact that it's less likely that a call to Pakistan will encounter a device such as an answering machine. Built-in PC 2 Phone QoS Management Tools track the ASRs for all termination facilities that receive calls routed through the PC 2 Phone Softswitch.

Backbone A very-high-speed network spanning the world from one major metropolitan area to another. Such networks are typically provided by national Internet service providers (ISPs). Local ISPs connect to the backbone in order to transport data.

Balance See Net Termination Balance.

Bandwidth The maximum data carrying capacity of a transmission link. For networks, bandwidth is usually expressed in bits per second (bps).

Billing Increment A call measurement unit, expressed in seconds. Calls that involve a fraction of a billing increment are rounded up.

Buyer A Registered User or a Member of PC 2 Phone that intends to purchase Termination Services.

Buyer Tariff The price at which a PC 2 Phone Member can send minutes to the destination associated with the Ordered Contract. Buyer Tariff equals the sum of the Seller Tariff and the Clearing Fee. Potential Buyers can indicate Tariffs that they are willing to pay for Termination Services in their Requests.

Call Establishment of (or an attempt to establish) a voice or data connection between two endpoints, or between two points which provide a partial link (e.g. a trunk) between two endpoints.

CDR (Call Detail Record) An automatically generated downloadable report for a requested time period. The report contains information on the number of calls, call duration, call origination and destination, and billed amount. PC 2 Phone Members use CDR reports to bill retail customers and settle with their partners on a wholesale level.

Clearing Fee The amount of money a Buyer pays to PC 2 Phone for the Clearing Service. Clearing Fee is calculated on a per minute basis.

Clearing Service The service that allows Internet Telephony Service Providers, Members of PC 2 Phone, to terminate each other's calls. The Clearing Service includes all the necessary system maintenance, authorization, routing, billing, administration, settlement, and collecting charges on behalf of the Members.

Codec Coder-decoder. A device that typically uses pulse code modulation to transform analog signals into a digital bit stream and digital signals back into analog signals. In Voice over IP, the Codec defines the voice coder rate of speech for a Dial peer.

Congestion The situation in which there are too many Packets present in the network, leading to performance degradation.

Contract A set of parameters that a PC 2 Phone Member using the Clearing Service establishes in order to receive traffic from and provide termination services to other PC 2 Phone Members. Contract details include the requested price per minute (Tariff), Grace Period, Minimum Call Duration, Billing Increment, Start Date, End Date, and one or more registered Gateways/Gatekeepers that will be terminating calls sent by a PC 2 Phone Member who has ordered this Contract.

Credit Line Past credit limit. A Buyer's initial Credit Line is equal to two times (2x) Deposit.

Deposit A deposit that establishes the Buyer's initial credit limit. The Deposit is refundable at the end of the Membership Agreement term provided that the Buyer has no outstanding liabilities with PC 2 Phone.

Dial-peer An addressable call endpoint -- a software structure that binds a dialed digit string to a voice port. A number of dial peers will exist on each router in the network, and at least two will be involved in making a call across the network, one on the originating end and one on the terminating end. In Voice over IP, there are two kinds of dial peers: POTS and VoIP. VoIP peers point to specific VoIP devices.

E.164 The international public telecommunication numbering plan. An E.164 number uniquely identifies a public network termination point and typically consists of three fields, CC (country code), NDC (national destination code), and SN (subscriber number), up to 15 digits in total.

E1 A wide-area digital transmission scheme (European): 2,048 Mbits/s; 30 channels, 64 Kbps each.

Endpoint SIP or H.323 terminal or Gateway. An endpoint can Call and be Called. It generates and terminates the information stream.

End Date Date determining the end of the period during which PC 2 Phone Members will terminate calls to the Gateways specified in a particular Contract. Expired Contracts (those with the End Date in the past) cannot be ordered.

Failed Call An attempted Call that does not receive the Connect message. Such calls are not billed.

Firewall A system designed to prevent unauthorized access to or from a private network. Firewalls can be implemented as hardware, software, or a combination of both. All messages entering or leaving the intranet pass through the firewall, which examines each message and blocks those that do not meet the security criteria specified on the firewall.

G.7xx A family of ITU standards for audio compression.

G.711 A 64 kbps PCM half-duplex codec (high quality, high bandwidth, minimum processor load).

G.723.1 A 6.4/5.3 kbps MP-MLQ codec (low quality, low bandwidth, high processor load due to compression).

G.726 A 40/32/24/16 ADPCM codec (good quality, medium bandwidth, low processor load).

G.728 A 16 kbps LD-CELP codec (medium quality, medium bandwidth, very high processor load).

G.729 An 8 kbps ACELP codec (medium quality, low bandwidth, high processor load).

Gatekeeper The central control entity that performs management functions in a Voice and Fax over IP network and for multimedia applications such as video conferencing. Gatekeepers provide intelligence for the network, including address resolution, authorization, and authentication services, the logging of Call Detail Records, and communications with network management systems. Gatekeepers control bandwidth, provide interfaces to existing legacy systems, and monitor the network for engineering purposes as well as for real-time network management and load balancing, .

Gatekeeping Fee The fee paid by PC 2 Phone Members to PC 2 Phone for the Gatekeeping Service.

Gatekeeping Service A PC 2 Phone Member may choose to use the PC 2 Phone Gatekeeping Service only, without credit risk management and clearing functions. The Gatekeeping Service includes system maintenance, authorization, routing, accounting for sent/received minutes, and other functions.

Gateway In IP telephony, a network device that converts voice and fax calls, in real time, between the public switched telephone network (PSTN) and an IP network. The primary functions of an IP gateway include voice and fax compression/ decompression, packetization, call routing, and control signaling. Additional features may include interfaces to external controllers, such as Gatekeepers or Softswitches, billing systems, and network management systems.

GKTMP (Cisco Gatekeeper Transaction Message Protocol) A proprietary Cisco protocol used for communication between the Cisco IOS Gatekeeper and external applications.

Grace Period The time interval at the beginning of a call, measured in seconds, that is not billed. PC 2 Phone Clearing Fee and Routing Fee do not apply to the grace period.

H.225 Protocols (RAS, RTP/RTCP, Q.931 call signaling) and message formats for H.323.

H.245 A protocol for capability negotiation, messages for opening and closing channels for media streams, etc. (i.e. media signaling).

H.323 An ITU-T "umbrella" of standards for Packet-based multimedia communications systems. This standard defines the different multimedia entities that make up a multimedia system - Endpoints, Gateways, Multipoint Conferencing Units (MCUs), and Gatekeepers -- and their interaction. This standard is used for many Voice-over-IP applications, and is heavily dependent on other standards, mainly H.225 and H.245.

IETF (Internet Engineering Task Force) One of two technical working bodies in the Internet Activities Board. The IETF meets three times a year to set technical standards for the Internet.

IPCB.net Short name for IP Clearing Board.

IP Clearinghouse An organization that provides clearing and settlement services in IP Telephony.

IP Precedence see Type of Service.

IP Telephony (Also called Voice over IP) Technology that allows voice phone calls to be made over the Internet or other Packet networks using a PC via Gateways and standard telephones. VoIP primarily builds on and complements existing standards, such as H.323 and SIP.

ISP Internet Service Provider.

ITSP Internet Telephony Service Provider.

ITU (International Telecommunications Union) An organization established by the United Nations to set telecommunications standards, allocate frequencies for various uses, and sponsor trade shows every four years.

ITU-T ITU standards for telecommunications.

Jitter The variation in the amount of Latency among Packets being received

Latency (Also called Delay) The amount of time it takes a Packet to travel from source to destination. Together, Latency and Bandwidth define the speed and capacity of a network.

Licensed Software The "harvester software" and any other software provided by PC 2 Phone to a Member for the purpose of record keeping, accounting, and/or access to PC 2 Phone services, and including PC 2 Phone-provided documentation.

Load Balancing Distribution of calls among terminating Gateways based on the Priorities and Weights assigned by the Buyer.

Member [of PC 2 Phone] An operator with IP Telephony minutes and/or termination capabilities; a Registered User that has signed the Membership Agreement and paid the Membership Fee, and, has thereby gained access to PC 2 Phone Clearing and Gatekeeping Services.

Member in Good Standing PC 2 Phone Member that maintains its Credit Line with PC 2 Phone in Good Standing.

Membership Agreement A signed agreement between a PC 2 Phone Member and PC 2 Phone, where PC 2 Phone provides Gatekeeping services or Clearing services between Sellers and Buyers. The Membership Agreement form is e-mailed to Members upon registering; the Members then sign their copy and send it back to PC 2 Phone.

Membership Fee A non-refundable one-time fee payable on becoming a Member of the PC 2 Phone network and thereby gaining access to PC 2 Phone Clearing and Gatekeeping Services. The Membership Fee does not include the initial Deposit.

MGCP (Media Gateway Control Protocol) A protocol complementary to H.323 and SIP, designed to control media gateways from external call control elements in decomposed gateway architectures. Working in conjunction with the Gateway Location Protocol (GLP), MGCP enables a caller with a PSTN phone number to locate the destination device and establish a session. It provides the gateway-to-gateway interface for the Session Initialization Protocol (SIP). MGCP is meant to simplify standards for the new Voice over Packet technology by eliminating the need for complex, processor-intense IP telephony devices, thus simplifying and lowering the cost of these terminals.

Minimum Duration The minimum billed call duration up to which all shorter calls are rounded in seconds.

Minute One (1) minute of communication resulting from a connection between a calling number and a called number.

Net Termination Balance The net of Termination Services purchased by a Member and Termination Services sold by the Member, determined in accordance with applicable Tariffs.

Offer An offer of Termination Services in a particular area. Offer details include the desired Seller Tariff and estimated traffic volume. Offers can be submitted by all Registered Users, with no commitments attached.

Order Contract An operation by which a PC 2 Phone Member commits to purchase termination services offered by another PC 2 Phone Member. The operation includes assigning Priorities and Weights to a collection of Contracts.

Order Contracts and Routes An operation by which a PC 2 Phone Member activates its own routes and commits to purchase termination services offered by other PC 2 Phone Members. The operation includes assigning Priorities and Weights to a collection of Routes and Contracts.

Order Route An operation by which a PC 2 Phone Member activates its own Route. The operation includes assigning Priorities and Weights to a collection of Routes.

Packet A piece of a message transmitted over a network. Large chunks of information are broken up into packets before they are sent across the Internet.

Priority A number (1-10) assigned to an ordered Contract or Route. If several Contracts/Routes for the same destination are ordered, PC 2 Phone will first attempt to terminate a call to the Contracts/Routes with the highest priority (1 is highest and 10 is lowest). If for some reason a connection cannot be established, Contracts/Routes with lower priority will be tried based on the assigned priorities. See also: Weight

Profile Information on a PC 2 Phone Registered User, including details such as the Contact Name, submitted to PC 2 Phone on registering. PC 2 Phone engineers use the Profiles to contact Members for troubleshooting purposes. This information is confidential and is accessible to authorized PC 2 Phone personnel only.

Protocol A common set of rules and signals that computers on the network use to communicate.

PSTN Public Switched Telephone Network.

Q.931 ISDN connection control protocol, roughly comparable to TCP in the Internet protocol stack. Q.931 doesn't provide flow control or perform retransmission, because the underlying layers are assumed to be reliable and the circuit-oriented nature of ISDN allocates bandwidth in fixed increments of 64 kbps. Q.931 does manage connection setup and breakdown. In H.323 scenario, this protocol is encapsulated in TCP and sent to port 1720.

QoS (Quality of Service) Ability of a network element (e.g., an application, host, or router) to have some level of assurance that its traffic and service requirements can be satisfied.

RAS (Registration, Admission, Status) A management protocol between terminals and Gatekeepers.

RateWatch PC 2 Phone subsystem that provides pricing information on IP Telephony termination.

Registered User An Internet user that has registered at PC 2 Phone Web Site and received an Account ID/Password.

Request A request for Termination Services in a particular area. Request details include the desired Buyer Tariff and estimated traffic volume. Requests can be submitted by all Registered Users, with no commitments attached.

Route A set of parameters predefined by PC 2 Phone to facilitate routing of traffic between the Gateways/Gatekeepers controlled by a PC 2 Phone Member either via ownership or via a partnership with the owner. Along with specifying other parameters, a PC 2 Phone Member using the Gatekeeping Service assigns to a Route values specifying the details of both originating and terminating Gateways/Gatekeepers.

RTP/RTCP (Real-time Transport Protocol/Real-time Control Protocol) An IETF specification for audio and video signal management. RTP is used to send encoded voice in UDP packets. RTCP is used to send statistical and control information for a VoIP channel, such as the number of bytes sent, commands to enable/disable echo suppression, etc.

Seller A Registered User or a Member of the PC 2 Phone that intends to sell Termination Services.

Seller Tariff The price requested by the Seller for terminating minutes at a specific destination.

SIP (Session Initiation Protocol) An application-layer control protocol, a Signaling protocol for Internet Telephony. SIP can establish sessions for features such as audio/videoconferencing, interactive gaming, and call forwarding to be deployed over IP networks thus enabling service providers to integrate basic IP telephony services with Web, e-mail, and chat services. In addition to user authentication, redirect and registration services, SIP Server supports traditional telephony features such as personal mobility, time-of-day routing and call forwarding based on the geographical location of the person being called.

Signaling The exchange of information between points in the network that sets up, controls, and terminates each telephone call.

Softswitch (Also called a Proxy Gatekeeper, Call Server, Call Agent, Media Gateway Controller, or Switch Controller) Software used to bridge a public switched telephone network and voice over Internet by separating the call control functions of a phone call from the media gateway (transport layer). Softswitch performs call control functions such as protocol conversion, authorization, accounting and administration operations.

Start Date Date determining the start of the period during which PC 2 Phone Members will terminate calls to the Gateways specified in a particular Contract. It is possible to order future Contracts (those with the Start Date in the future) in advance.

T1 A wide-area digital transmission scheme (North American): 1,544 Mbits/s; 24 channels, 64 Kbps each.

Tariff The price of Termination Services per minute specified in a Contract. See also Seller Tariff, Buyer Tariff.

TCP (Transmission Control Protocol) Connection-oriented transport layer protocol that provides reliable full-duplex data transmission. TCP is part of the TCP/IP protocol stack.

Termination Contract See Contract.

Termination Services The completion by a PC 2 Phone Member of a telephone call originated by another Member.

ToS (Type of Service) An 8-bit field in the IP datagram header that identifies the relative priority of one packet over another. Networking devices use this field to prioritize packets appropriately and place them in different queues if necessary.

UDP (User Datagram Protocol) A connectionless transport layer protocol in the TCP/IP protocol stack. UDP is a simple protocol that exchanges datagrams without acknowledgment or guaranteed delivery. Error processing and retransmission must be handled by other protocols.

Weight A number (10-100) assigned to a Contract or Route when ordering the Contract/Route. If several Contracts/Routes for the same destination have the same Priority assigned, calls to the destination are distributed among the Contracts/Routes according to their relative Weights