Epygi Manual III User Manual page 47

QX50/QX200/QX2000 Manual III: Extension User's Guide
Network Address Translation (NAT) - is used to allow LAN devices that do not have their own static IP addresses to connect to the Internet sharing an
IP address. NAT will assume control of assigning their IP address. Furthermore, the NAT takes care that packets will reach the LAN PC that originated the
traffic. This mechanism is absolutely transparent for the users (or the PCs in the LAN).
Network Time Protocol (NTP) - a protocol that is used for time counting in the Internet, based on the atomic clocks with the precision in milliseconds.
This is the recommended protocol for synchronizing the time of hosts in the network.
P
Packetization Interval - the time interval between two RTP packets of the same stream. If the interval is increased, the overhead is decreased but the
voice quality might deteriorate. If the interval is decreased, the network load is increased and the delay is reduced.
Password - a secret alphanumeric string used to identify and to allow the user to have access to a system.
PCM - a form of modulation in which the information signals are sampled at regular intervals and a series of pulses in coded form are transmitted
representing the amplitude of the information signal at that time.
Point-to-Point Protocol (PPP) - allows a computer to connect to the Internet with a standard dial-up telephone line and a high-speed modem and to
enjoy most of the benefits of the direct connection.
Point-to-Point Tunneling Protocol (PPTP) - enables virtual private networking - enabling secure remote access to corporate networks over the
Internet.
POTS (Plain Old Telephone Service) - is the standard telephone service that most homes use. It is also referred to as the PSTN, or the Public Switched
Telephone Network
Private Branch Exchange (PBX) - a telephone switch owned privately, usually by a large company. If it owns a PBX, a company does not need to lease a
telephone line for each telephone set at a site.
Proxy server - an intermediate device that receives SIP requests from a client and then initiates requests on the client's behalf.
Public Switched Telephone Network (PSTN) - refers to the local telephone company.
R
Real-Time Transport Protocol (RTP) - the Internet-standard protocol for the transport of real-time data, including audio and video, allows applications
to synchronize audio and video information. RTP connections are established between servers across the Internet after voice has been converted to IP
format. RTP is used in virtually all Voice-over-IP architectures, for videoconferencing, media-on-demand, and other applications.
Real-Time Transport Control Protocol (RTCP) - is the control protocol that works in conjunction with RTP. RTCP control packets are periodically
transmitted by each participant in an RTP session to all other participants. Feedback of information to the application can be used to control performance
and for diagnostic purposes.
Registration - procedure of user subscribing to a server. Usually some personal parameters such as username, password, etc., are required upon
registration.
Remote Testing - remote connection from the Epygi Support office to the customer's QX for testing and/or for troubleshooting.
Router - A device that determines the next network point to which a data packet should be forwarded enroute toward its destination. The router is
connected to at least two networks and determines which way to send each data packet based on its current understanding of the state of the networks it
is connected to. Routers create or maintain a table of the available routes and use this information to determine the best route for a given data packet
RSA - is an asymmetric key system. It must be available on both sides of the VPN and generates on each side a different pair of keys, a private and a public
key.
S
Security Parameter Index (SPI) - is an index to keep VPN tunnels distinct. A security association is defined by destination, protocol and SPI. Without the
SPI, connections to the same gateway using the same protocol would not be distinguishable.
Session Initiation Protocol (SIP) - is an application-layer control protocol that can establish, modify and terminate multimedia sessions or calls. SIP is
increasingly used for Internet telephony signaling, in gateways, PC phones, softswitches, and softphones, but it is not limited to Internet telephony, and
can be used to initiate and manage any type of session, including video, interactive games, and text chat.
Signaling - a process of sending a transmission signal over a physical medium for communication.
Silence Suppression - a method that allows disabling RTP packet transmission when there is no voice activity. This feature helps to avoid extra traffic
when the RTP stream doesn't contains voice data.
Simple Network Management Protocol (SNTP) - the Internet standard protocol developed to manage nodes on an IP network.
SIP address - unique address of the users registered on the SIP server. The address can be used to connect the user. The full SIP address has the following
format: "display name" <username@ipaddress:port>.
SIP server - this server is used for registering users. It gives a possibility to make IP connections between users registered on the same SIP server.
Software - PC programs.
QX50/QX200/QX2000; (SW Version 6.0.x) 47