Glossary Section "V" ( Definitions )
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V.35 is a balanced, high speed serial
interface. A balanced interface means
that there are two leads for each data
and clock line. Generally a V.35 port is physically a 34 pin Winchester
connector. The V.35 can handle both sync and async data but in practice it is
used for sync data.
V.36 is a physical 37 pin connector frequently used for RS-449 signaling.
VAC Volts of Alternating Current
VAN Value Added
generally a packet switched network with access to data bases, protocol conversion, etc.
VBR Variable Bit Rate. A data
transmission that can be represented by irregular grouping of bits or cell payloads
followed by unused bits or cell payloads. Most applications other than voice circuits
generate VBR traffic patterns. VBR is an ATM service type and is divided into Real-Time
VBR and non-Real-Time VBR, in which the ATM network guarantees to meet the transmitter's
bandwidth and Quality of Service requirements.
has two meanings. The most common is Virtual Circuit. Sometimes VC is used
to mean Voice Compression (See
VCI Virtual Circuit (or
Channel) Identifier; part of a packet/frame address header
vCPE Virtual Customer Premises Equipment delivers various services like firewalls, routing and VPN service by using software instead of having dedicated hardware.
VDC Volts of Direct Current
VCSEL Vertical Cavity Surface Emitting Laser
VDSL Very high rate Digital
Subscriber Line. Up to 54 Mbps with a focus on video. Generally has a limited
distance (less than 4000 feet) and has limited availability.
Veronica A Gopher utility
which effectively searches Gopher servers based on a user's list of keywords. The name was
chosen to be a "mate" to another utility named "Archie." It later
became an acronym for Very Easy Rodent Oriented Netwide Index to Computer Archives.
VG Voice Grade
VGPL Voice Grade Private Line
virtual circuit A network
service which provides connection-oriented service regardless of the underlying network
VLAN is a virtual LAN. In other words, connected devices behave as if they are connected to the same physical wire even thought they may be separated by a WAN connection. VLANs also help to improve network
security over the WAN.
VLSI Very Large Scale
Integration, putting thousands of transistors on a single chip.
VoIP Voice over IP
is a technology to allow voice communications over an IP network.
VPI Virtual Path Identifier.
VCI in ETSI version of ATM.
VPN Virtual Private Network.
VPN allows IP traffic to travel securely over a public TCP/IP network by encrypting all
traffic from one network to another. A VPN uses "tunneling" to encrypt all
information at the IP level. One of Delta Communications Group's specialties.
VT Virtual Terminal. The OSI
Virtual Terminal Service. Similar to Telnet.
There are several types of voice compression
but the idea is same. Basically
voice compression is used to reduce the amount of bandwidth required to transmit
voice. One part of this is to remove pauses in speech from the transmission itself. The
pauses are represented by data characters that indicate where the pauses belong but without the need for transmitting the pauses
themselves. They are removed at the originating side and reinserted at the receiving end. Actually a great deal more goes
into the algorithms used than just pauses. Various manufacturers use different techniques. Some are more
effective than others for delivering quality voice transmission. (equipment
for voice compression)
vPOTS Very Plain Old Telephone
Service; no switching
VQC Vector Quantizing Code; a
voice compression technique that runs at 32 and 16 kbit/s.
VQL Variable Quantizing Level;
voice encoding method.
VRML Virtual Reality Modeling
Language. VRML is a language much like HTML for getting data on the Web. The 3D nature of
VRML is where the two specs depart. Mark Pesce explained VRML to be, "...a language
for describing multi-user interactive simulations-virtual worlds networked via the global
Internet and hyperlinked within the World-Wide Web."
VSAT Very Small Aperture
VTAM Virutal Terminal Access
Method, an SNA protocol.
Telecommunications Network Service
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