RADVISION术语表

Glossary (B)

# - A - B - C - D - E - F - G - H - I - J - K - L - M - N
O- P - Q - R - S - T - U - V - W - X - Y - Z

B2BUA (BACK-TO-BACK USER AGENT)
A Back-to-Back User Agent (B2BUA) is a method of implementing call control servers in SIP. A B2BUA retains control over the call during the duration of it while the proxy is typically involved only in the setup phase of the call.

B CHANNEL
Bearer channel. In ISDN communications, a B channel transmits data or voice at 64 or 56 Kbps.

BANDWIDTH
The transmission capability of a communications channel. In analog communications, bandwidth is measured in Hertz (cycles per second). In digital communications it is measured in bits per second (bps). Ethernet bandwidth is typically 10, 100 or 1000 Mbps.

BASE STATION
A two-way radio installation in a fixed location, used to communicate with one or more mobile or portable radio transceivers. They are typically used by two-way radios such as mobile phones, portable phones and wireless routers.

BEARER
Refers to a service that allows transmission of information signals between network interfaces.

BER (BIT ERROR RATIO)
The ratio of the number of bits incorrectly received to the total number of bits sent during a specified time interval. The error ratio is usually expressed in scientific notation; for example, 2.5 erroneous bits out of 100,000 bits transmitted would be 2.5 out of 105 or 2.5 *10-5. The bit error ratio will be affected by both the data transmission rate and the signal power margin. BER directly affects the media quality of calls.

BEST EFFORT QoS/SERVICE
Best effort delivery describes a network service in which the network does not provide any special features that ensure the quality of the service delivered.

BILLING
Billing in a telecommunications environment refers to the capacity of a service provider to capture, rate, and bill communications events. These events include voice, video, data, and electronic content.

BONDING
Bandwidth on Demand. Increasing the bandwidth of a call by linking two or more B channels of an ISDN line.

BORDER GATEWAY
A gateway at the border between two networks. Responsible for enforcing network policies, such as security, QoS, type of service, priority, authorization, etc.

BRI (BASIC RATE INTERFACE)
An ISDN subscriber interface supporting two bearer B channels at 64 Kbps and one data D channel at 16 Kbps.

BRIDGE (CONFERENCE BRIDGE)
A connection between two or more conference sites, enabling data, voice or video traffic to pass simultaneously between the sites. Video conferencing bridges are often called MCUs.

BRIDGE (INTER-NETWORK)
Gateways, interworking gateways, session border controllers (SBCs) and other entities that interconnect between networks are often referred to as bridges.

BROADBAND
A method of transmitting larger amounts of data, voice and video than telephony networks allow. Traditionally connecting to the Internet meant dialing a specific number from a PC via a fax/modem at a typical speed of 56kbps (narrowband) to then gain access the internet or the WWW (World-Wide-Web). As speeds improved the term Broadband became popular, and is often accompanied by the speed, or bandwidth, of information or data (i.e. 512kbps, 1Mbps, 8Mbps) that travels down a fiber. optic cable or telephone line per second depending on your choice of service. In ISDN, broadband channels support rates above the primary E-1 (2.048 Mbps) and T-1 (1.544 Mbps) rate.

BROADCAST
Transmission of data to everybody on the network or network segment.