Question | Answer |
assured forwarding | a forwarding specification |
af | allows routers to assign data streams one of several priorization levels |
analog telephone adapter | an internal or external adapter that converts analog telephone signals into packet switched voice signals and vice versa |
differentiated service | a technique for ensuring quality of service by prioritizing traffic |
expediated forwarding | a forwarding specification that assigns each data stream a minimum departure rate from a given node |
ef | technique circimvents delays that slow normal data from reaching its destination on time and in sequence |
endpoint | any client server or gateway communicating on the network |
fax gateway | translate IP fax data into analog fax data and vice versa |
fax gateway | emulate and interpret conventional fax signaling protocols when communicating with a conventional fax machine |
fax over ip | a service that transmits faxes over tcp/ip network |
h.225 | session layer call signaling protocol |
h.225 | responsible for call or videoconferencing setup between two nodes on a VoIP network, indicating node status, requesting additional bandwith and call termionation |
h.245 | a session layer control protocol |
h.245 | responsible for controlling a session between two nodes |
h.323 | describes an architecture and a suite of protocols for establishing and managing multimedia services sessions on a packet switched network |
h.323 gatekeeper | authorize and authenticate terminals and gateways,manage bandwith,and oversee call routing,accounting and billing |
h.323 gateway | a gateway that provides translation between network devices running h.323 signaling protocols and devices running other types of signaling protocols |
h.323 terminal | any node that provides audio visual or data information to another node |
h.323 zone | collection of h.323 terminals,gateways,and mcus that are managed by a single h.323 gatekeeper |
internet telephony | the provisions of telephone service over the internet |
ip-pbx | a private switch that accepts and interprets both analog and digital voice signalsconnects with both traditional pstn lines and data networks |
ip-pbx | transmits and receives ip based voice signals to and from other network connectivity devices,routers and gateways |
ip telephone | designed to transmit and receive only digital signals.used for VoIP on a tp/ip based networks |
ip television | a serivce in which tv signals from broadcast or cable networks travel over packet switch networks |
multipoint controlunit | a computer that provides support for multiple h.323 terminals, for ex several workstations participating in videoconferencing, and manages communication between them. also known as video bridge |
media gateway | a gateway capable of accepting connections from multiple devices ,for example ip telephones,fax machines, |
media gateway controller | a computer that manages mu,tiple media gateways and facilitates the exchange of call information between these gateways |
media gateway control protocol | used for communication between media gateway controllers and media gateways |
mgcp | defined in rfc 2507, the most popular media gateway control protocol used on converged networks |
private branch exchange | a telephone switch used to connect calls within a private organization |
proxy server | a server thataccepts requests for location information from user agents, then queries the nearest registrar server on behalf of those user agents |
redirect server | a server that accepts and responds to requests from user agents and sip proxy servers for location information on recipients that belong to external domains |
registrar server | a server that maintains a database containing information about the locations(network addressses) of each user agent in its domain.when a user agent joins the network it transmits its location information to the sip registrar server |
resource reservation protocol | a QoS technique that attempts to reserve a specific amount of network resources for a transmission before the transmission occurs |
real time transport protocol | a transport layer protocol used with voice and video transmission.operates on top of udp and provides information about packet sequence to help receiving nodes detect delay and packet loss. |
real time transport protocol | assigns packets a timestamp that corresponds to when the data in the packet was sampled from the voice or video stream.this timestamp helps the receiving node synchronize incoming data |
set top box | a device that decodes digital video signals and issues them to the tv.also communicate with content servers to manage video delivery |
signaling | the exchange of information between the components of a network or system for the purposes of establishing,monitoring, or releasing connections as well as controlling system operations |
session initiation protocol | a protocol suite codified by the ietf,in rfc 2543, as a set of session layer signaling and control protocols for multiservice,packet based networks.performs much the same functions as the h.323 signaling protocols perform. |
sip | was developed as a more efficient alternative to h.323 ,before h.323 was revised to expedite its call setup functions. |
softphone | a computer configured to act like an IP telephone.present the caller with a graphical representation of a telephone dial pad and can connect to a network via a LAN,wan,ppp dial-up connection or leased line |
signaling system 7 | set of standards established by the itu for handling call signaling on the public switched telephone network |
streaming video | a service in which video signals are compressed and delivered over the internet in a continuous stream so that a user can watch and listen even before all the data has been transmitted |
toll bypass | a cost saving benefit that results from organizations completeing long distance telephone calls over their packet switched networks,bypassing tolls charges by common carriers on comparable pstn calls |
unified messaging | the centralized management of multiple types of network based communications,such as voice,video and fax |
user agent | a user agent client or user agent server |
user agent client | end user devices such as workstation,cell phones.initiates a sip connection |
user agent server | a server that responds to user agents requests for session initiation and termination |
video on demand | a service in which a video stored as an encoded file is delivered to a viewer upon his request |
video over ip | any type of video service,video conferencing,and streaming video,that delivers video signals over packet switched networks using the tcp/ip protocol suite |
video phone | a type of phone that includes a screen and can decode compressed video and interpret transport and signaling protocols necessary for conducting videoconference sessions. |
videoconferencing | the real time reception and transmission of images and audio among two or more locations |
voice over atm | |