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Wireless Networking Glossary
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V
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| VAR | Value-added Reseller |
| VAS | Value Added Service |
| VBR | Variable Burst Rate. Adds ability to statistically oversubscribe user traffic. Classified by network according to a guaranteed sustained cell rate (SCR) or a peak cell rate (PCR), and a maximum burst size. Managed at "guaranteed" and "if available" rate. ‘VBR-rt’ commonly used to deliver time-sensitive applications real time, such as voice and real-time video. Provides better congestion control and latency guarantees than non-real time ‘VBR-nrt’. See ABR and CBR. |
| VCI | Virtual Channel Indentifier. ID number used to label ATM cells; indicates to which virtual circuit the cell belongs. |
| VDSL | Very high speed DSL, providing about 58 Mbit/sec in both directions. Available as asymetric (see ADSL) or symmetric (see SDSL). See VDSL Alliance |
| VHF | Very High Frequency. 30-300 MHz (used in the US and Canada as television channels 2-13) |
| VID | VLAN Identification. Identification number applied to VLAN-tagged Ethernet frame indicating to which VLAN frame it belongs. |
| Virtual Channel | Point-to-point or point-to-multipoint connection between ATM end stations. A virtual channel can be either switched or permanent. It is identified by the combination of VCI and VPI. |
| VLAN | Virtual LAN. LAN with devices that aren’t physically connected to same segment. Maps workstations on some other basis than geographic location (for example, by department, type of user, or primary application). Switches that are VLAN-compliant recognize VLAN-enabled packets, route only to authorized recipients. |
| VLAN Tunneling | See Tunneling. |
| VoIP | Voice Over IP. Voice information delivered using Internet Protocol. Packet-switched network vs. TDM, which is circuit-switched via PSTN. Derives from VoIP Forum, an effort by major equipment providers to promote use of ITU-T H.323 standard for sending voice (audio) and video using IP on public Internet and within Intranets. Using VoIP, end-user positions VoIP device at gateway to receive packetized voice transmissions from users within company. Device then routes transmissions to other parts of Intranet (LAN or WAN) or, over PSTN, while avoiding tolls. |
| VP | Virtual Path |
| VPI | Virtual Path Identifier. See Virtual Channel. |
| VPN | Virtual Private Network. Umbrella term that refers to all technologies enabling secure communications over public Internet. VPN-related technologies include tunneling, authentication and encryption. See Tunneling. |
| VSAT | Very Small Aperture Terminal. Satellite system for home and business users. Equipment at end user site that interfaces with outside antenna with transceiver. Transceiver receives or sends signal to satellite transponder. |