TermV

V.21		Capable of only 300 bps, it is an international standard used mainly outside of the U.S.
V.22		Capable of 1200 bps at 600 baud. Used mainly outside the U.S.
V.22bis		Used in the U.S. and out, it is capable of 2400 bps at 600 baud.
V.23		Used mainly in Europe, it allows the modem to send and receive data at the same time at 75 bps.
V.29		A one-way (half-duplex) standard that is used mostly for fax machines. Capable of 9600 bps.
V.32		A full-duplex standard capable of 9600 bps at 2400 baud. V.32 modems automatically adjust their transmission speeds based on the quality of the lines.
V.32bis		A second version of V.32, it is capable of 14,400 bps. It will also fallback onto V.32 if the phone line is impaired.
V.32terbo		The third version of V.32, capable of 19,200 bps.
V.34		Capable of 28,000 bps or fallback to 24,000 and 19,200. This standard is backwards compatible with V.32 and V.32bis.
V.34bis		Capable of 33,600 bps or fallback to 31,200.
V.42		Same transfer rate as V.34 but is more reliable because of error correction.
V.42bis		A data compression protocol that can enable modems to achieve a data transfer rate of 34,000 bps.
V.44		Allows for compression of Web pages at the ISP end and decompression by the V.44-compliant modem, so transmitting the same information requires fewer data packets.
V.90		The fastest transmissions standard available for analogue transmission, it is capable of 56,000 bps.
V.92		Transmits at the same speed as V.90 but offers a reduced handshake time and an on-hold feature.
V.110		A rate adaption standard, based on fixed frames, that subdivides the ISDN channel so that it can carry one lower-speed data channel.
VAD	Voice Activity Detection	When enabled on voice port or a dial peer, silence is not transmitted over the network, only audible speech. When VAD is enabled, the sound quality is slightly degraded, but the connection monopolizes much less bandwidth.
VAN	Value-Added Network
VANS	Value Added Network Services
VAR	Value-Added Reseller
VB	Virtual Bandwidth	Channel capacity calculated to allow for the over subscription of channel usage.
VBI	Vertical Blanking Intervals
VBR	Variable Bit Rate	QoS class defined by the ATM Forum for ATM networks. VBR is subdivided into a real time (RT) class and non-real time (NRT) class. VBR (RT) is used for connections in which there is a fixed timing relationship between samples. VBR (NRT) is used for connections in which there is no fixed timing relationship between samples, but that still need a guaranteed QoS.
VC	Virtual Circuit	A link that behaves like a dedicated point-to-point line or a system that delivers packets in sequence, as would happen on an actual point-to-point network.
VCC	Virtual Channel Connection	Logical circuit, made up of VCLs, that carries data between two end points in an ATM network. Sometimes called a "virtual circuit connection."
VCD	Virtual Circuit Descriptor
VCI	Virtual Channel Identifier	16-bit field in the header of an ATM cell. The VCI, together with the VPI, is used to identify the next destination of a cell as it passes through a series of ATM switches on its way to its destination. ATM switches use the VPI/VCI fields to identify the next network VCL that a cell needs to transit on its way to its final destination. The function of the VCI is similar to that of the DLCI in Frame Relay. Logical channel number in B-ISDN, part of cell header
VCL	Virtual Channel Link	Connection between two ATM devices. A VCC is made up of one or more VCLs.
VC-n	Virtual Container	E.g., STM-1 uses VC-4 container
VDSL	Very High Bit Rate Digital Subscriber Line	An asymmetric DSL technology that offers about eight times the performance of ADSL. The downside is that it requires a fibre-optic line from the central office (CO) to the subscriber's neighbourhood. Because infrastructure changes are required in the local loop, VDSL is considered a specialized and long-term technology.
VDT	Video Display Terminal
VERONICA	Very Easy Rodent Oriented Netwide Index to Computer Archives	Gopher utility that effectively searches Gopher services based on a user's list of keywords.
VF	Variance Factor	One of three link attributes exchanged using PTSPs to determine the available resources of an ATM network. VF is a relative measure of CRM normalized by the variance of the aggregate cell rate on the link.
Virtual Ring		Entity in an SRB network that logically connects two or more physical rings together either locally or remotely. The concept of virtual rings can be expanded across router boundaries.
VLAN	Virtual Local Area Network	In a switched network, a logical collection of devices, such as all the workstations and servers with a particular IP subnet address, which are grouped into a broadcast domain.
VLI	Virtual LAN Internetwork	Internetwork composed of VLANs.
VLR	Visitor Location Register	A database that stores the necessary information to handle calls while mobile subscribers are visiting outside their home areas.
VLSI	Very Large Systems Integration
VLSM	Variable-Length Subnet Mask	Ability to specify a different subnet mask for the same network number on different subnets. VLSM can help optimize available address space.
VMAC	Virtual Media Access Control
VNS	Virtual Network Service
VoATM	Voice Over ATM	Voice over ATM enables a router to carry voice traffic (for example, telephone calls and faxes) over an ATM network. When sending voice traffic over ATM, the voice traffic is encapsulated using a special AAL5 encapsulation for multiplexed voice.
VoATM Dial Peer		Dial peer connected via an ATM network. VoATM peers point to specific VoATM devices.
VOD	Video-On-Demand
VoFR	Voice-over-Frame Relay	A term applied to a set of facilities for managing the delivery of voice information using frame relay.
VoHDLC	Voice Over HDLC	Voice over HDLC enables a router to carry live voice traffic (for example, telephone calls and faxes) back-to-back to a second router over a serial line.
Voiceband		A transmission channel with a nominal 4-kHz bandwidth suitable for voice transmission.
VoIP	Voice over Internet Protocol	A category of hardware and software that allows people to use the Internet to make telephone calls. Currently, VoIP does not offer the same quality of telephone service as direct telephone connections. Also known as Internet telephony, and Voice over the Internet.
VP	Virtual Path	Contains virtual circuits that are to be switched together to a common destination such as an inter-exchange carrier.
VPDN	Virtual Private Dial-up Network
VPI	Virtual Path Identifier	8-bit field in the header of an ATM cell. The VPI, together with the VCI, is used to identify the next destination of a cell as it passes through a series of ATM switches on its way to its destination. ATM switches use the VPI/VCI fields to identify the next VCL that a cell needs to transit on its way to its final destination. The function of the VPI is similar to that of the DLCI in Frame Relay.
VPL	Virtual Path Link	Within a virtual path, a group of unidirectional VCLs with the same end points. Grouping VCLs into VPLs reduces the number of connections to be managed, thereby decreasing network control overhead and cost. A VPC is made up of one or more VPLs.
VPN	Virtual Private Network	A restricted network that uses pubic wires to connect nodes. A VPN provides a way to encapsulate, or "tunnel", private data cheaply, reliably, and securely through a public network, usually the Internet.
VRML	Virtual Reality Modeling Language	Specification for displaying 3-dimensional objects on the World Wide Web.
VSAT	Very Small Aperture Terminal
VSELP	Vector Sum Excited Linear Prediction
VSI	Virtual Switch Interface
VTAM	Virtual Telecommunications Access Method	Set of programs that control communication between LUs. VTAM controls data transmission between channel-attached devices and performs routing functions.
VT-n	Virtual Tributary Level n	SONET format for mapping a lower-rate signal into a SONET payload. For example, VT-1.5 is used to transport a DS-1 signal.
VTP	Virtual Terminal Protocol	An application for establishing a virtual terminal connection across a network.