Glossary
V
46 terms.
- VALARM
The iCalendar component for a reminder, nested in a VEVENT or VTODO. It has an ACTION (AUDIO, DISPLAY or EMAIL) and a TRIGGER.
Plain language An iCalendar component for a reminder nested in an event or task.
- Validating resolver
A security-aware resolver that checks DNSSEC signatures itself rather than trusting an upstream server to do it.
Plain language A security-aware resolver that checks DNSSEC signatures itself.
Used in RFC 2535 RFC 3008 RFC 3833 RFC 4033 RFC 4035 RFC 4955 RFC 4956 RFC 5074 RFC 6147 RFC 6672 RFC 6840 RFC 6975 RFC 7583 RFC 7646 RFC 7901 RFC 8027 RFC 8145 RFC 8198 RFC 8499 RFC 8657 RFC 8749 RFC 8806 RFC 8901 RFC 8914 and 5 more
- Validator
A piece of metadata about a resource, such as an entity-tag or a last-modified date, used in a precondition to check whether a stored copy is still current.
- Variable binding
In SNMP, a pairing of a variable's name (an OBJECT IDENTIFIER) with its value, or with an exception that explains why no value was returned.
Plain language In SNMP, a pairing of a variable's name with its value or an exception explaining why no value was returned.
- Variant
One of several versions of the same resource that live under a single URI, for example the French or the English edition of a page. A client or server picks among them by comparing their properties to its needs.
- Variant label
A label computed from an original label by substituting code points with their defined variants. Registry policy can block it or reserve it for the same owner as the original.
Plain language A label computed from an original label by substituting code points with their defined variants.
- VC merge
The ability of an ATM label switching router to map several incoming virtual circuit labels onto one outgoing label, so that traffic from several upstream routers can share a single label downstream.
Plain language Combining several incoming labels into one outgoing label, so the router does not need a separate label for each upstream router.
- vCard
A standardized text format for electronic business cards and contact information, defined in RFC 6350.
Plain language A standardized text format for electronic business cards and contact information.
Used in RFC 2426 RFC 2739 RFC 4770 RFC 6351 RFC 6352 RFC 6474 RFC 6493 RFC 6868 RFC 6869 RFC 7095 RFC 7852 RFC 8605 RFC 9553 RFC 9554 RFC 9555
- Vector Graphics
Display using lines, points, and shapes, where positions are specified by coordinates rather than as a grid of pixels. The alternative is raster graphics.
Plain language Display using lines, points and shapes specified by coordinates rather than as a pixel grid.
- Vendor-Specific Attribute
A RADIUS attribute (number 26) that lets a vendor define its own data, identified by the vendor's Private Enterprise Code. The vendor assigns the attribute types inside it.
Plain language A RADIUS attribute letting a vendor define its own data identified by a Private Enterprise Code.
- Vendor-Specific Extension (VSE)
An extensible mechanism in Mobile IPv4 that allows vendors to add custom fields to registration messages without modifying the core protocol.
Plain language An extensible mechanism in Mobile IPv4 allowing vendors to add custom fields to registration messages.
- Verifiable Data Structure
An append-only data structure, that can produce signed proofs about its contents, for example that an entry was included. Transparency services use one to record signed statements.
Plain language An append-only data structure that can produce signed proofs about its contents.
- Version negotiation
The process by which two endpoints agree on which version of a protocol to use. It succeeds when they find a version both support.
Plain language The process by which two endpoints agree on which protocol version to use.
- VEVENT
The iCalendar component for a scheduled amount of time, such as a meeting or an all-day event. It needs a UID and DTSTAMP.
Plain language An iCalendar component for a scheduled amount of time such as a meeting or all-day event.
Used in RFC 2445 RFC 2446 RFC 5545 RFC 6047 RFC 7265 RFC 7529 RFC 7986 RFC 9073 RFC 9074
- View subtree
A branch of the object identifier tree that a MIB view includes or excludes. A view entry names a subtree and a bit mask, so that one entry can cover a family of subtrees at once.
Plain language A named branch of the management tree that a view either shows or hides.
- View-based Access Control Model
The SNMP access control mechanism (VACM) that decides which parts of a MIB each group of users may read or write. Access is configured as named views of the object tree.
- Virtual circuit
A connection-oriented network service in which the network sets up and remembers a path for a conversation. RFC 1958 says datagrams are better than classical virtual circuits because they avoid state inside the network.
Plain language A connection-oriented network service where the network sets up and remembers a path.
Used in RFC 466 RFC 852 RFC 874 RFC 877 RFC 878 RFC 883 RFC 955 RFC 1090 RFC 1294 RFC 1356 RFC 1382 RFC 1483 RFC 1490 RFC 1577 RFC 1581 RFC 1582 RFC 1586 RFC 1596 RFC 1598 RFC 1604 RFC 1613 RFC 1680 RFC 1755 RFC 1772 and 90 more
- Virtual Circuit Connectivity Verification
A protocol for testing the health and connectivity of pseudowire circuits, using different control channel types such as the Control Word, Router Alert Label, or TTL expiration.
Plain language A protocol testing the health and connectivity of pseudowire circuits.
Used in RFC 4717 RFC 5085 RFC 5641 RFC 6073 RFC 6136 RFC 7079 RFC 7338
- Virtual concatenation
A method that bonds several TDM signals into one larger logical connection by striping data bytes across them. The member signals can travel separately.
Plain language Bonding several TDM signals into one larger logical connection by striping data bytes across them.
- Virtual File
A standard representation of file data independent of local system formats, identified by dataset name, date, time, originator and destination.
Plain language A standard representation of file data independent of local system formats.
- Virtual Gateway
A collection of policy gateways from two adjacent domains that serves as the only inter-domain connection point recognized by IDPR, providing redundancy and load sharing.
Plain language A collection of policy gateways from two adjacent domains serving as one inter-domain connection point.
- Virtual hosting
Running many separate sites or services, each with its own name, from a single server or network address.
Plain language Running many separate sites or services each with its own name from a single server.
Used in RFC 2616 RFC 2817 RFC 3546 RFC 4227 RFC 5922 RFC 5923 RFC 6066 RFC 7151 RFC 7671 RFC 7711 RFC 7712 RFC 9112
- Virtual Interface
A software abstraction representing the network link between a VPN client and gateway, created by the VPN software to hold the assigned IP addresses and traffic policies.
Plain language A software abstraction representing the network link between a VPN client and gateway.
- Virtual link
A logical OSPF connection between two routers that are not directly attached, carried across the network using a reachable unicast address of the far endpoint.
Plain language A logical OSPF connection between two routers not directly attached.
- Virtual network
A network a provider offers a customer to use as though it were a physical network, though it is built from resources of underlying networks.
Plain language A network a provider offers a customer to use as though it were physical.
- Virtual Network Identifier
A number carried in a tunnel header that says which virtual network a packet belongs to. Geneve gives it 24 bits, and the control plane decides what it means for forwarding.
Plain language A number carried in a tunnel header indicating which virtual network a packet belongs to.
- Virtual Network Topology
The topology formed by lower-layer LSPs that are advertised as traffic engineering links in the higher layer.
Plain language The topology formed by lower-layer LSPs advertised as traffic engineering links.
- Virtual Private Network
A private network service built on top of shared infrastructure. Its members can use their own private address space, which may overlap with other networks.
Plain language A private network service built on shared infrastructure using private address space.
Used in RFC 2684 RFC 2735 RFC 4026 RFC 4031 RFC 4176 RFC 4365 RFC 4847 RFC 6513 RFC 6624 RFC 6867 RFC 6882 RFC 8049
- Virtual Private Network
An encrypted network tunnel that allows two devices to communicate securely over the internet as if they were on the same private network.
Plain language An encrypted network tunnel allowing two devices to communicate securely over the internet.
Used in RFC 2458 RFC 2685 RFC 2764 RFC 4093 RFC 4110 RFC 4176 RFC 4684 RFC 4923 RFC 4943 RFC 5265 RFC 5684 RFC 6071 RFC 6193 RFC 6418 RFC 6926 RFC 7297 RFC 7359 RFC 7524 RFC 7556 RFC 8277 RFC 8534 RFC 9181 RFC 9182 RFC 9252 and 1 more
- Virtual Reassembly Buffer
A table kept by a forwarding node that remembers where the fragments of each datagram come from and go to, so fragments can be passed on without storing the whole packet.
Plain language A table tracking where fragments of each datagram come from and go to.
- Virtual Router
An abstract router, identified by a VRID and a set of IP addresses, that several physical routers on a LAN share. One of them acts for it at a time.
Plain language An abstract router identified by a VRID and IP addresses that physical routers share.
Used in RFC 2281 RFC 2338 RFC 2917 RFC 3768 RFC 5798 RFC 6527 RFC 9568
- Virtual Routing and Forwarding
A separate routing and forwarding table kept inside one router, so that different customers or services can be kept apart. Interfaces are assigned to a VRF.
Plain language A separate routing and forwarding table inside one router for different customers.
- Virtual Routing and Forwarding (VRF)
A separate routing and forwarding table instance on a router, allowing multiple logical routers to coexist. Used in VPNs to isolate customer traffic.
Plain language A separate routing and forwarding table instance on a router allowing multiple logical routers.
- Virtual tributary
A small payload container carried inside a SONET Synchronous Payload Envelope, for example 28 VT1.5s in one envelope. In SDH the equivalent is a Virtual Container.
Plain language A small container of payload carried inside a larger optical frame.
- VLAN
A virtual LAN, identified by a 12-bit VLAN ID, that splits one physical Ethernet network into separate logical networks.
Plain language A virtual LAN identified by a 12-bit VLAN ID that splits one physical Ethernet network.
Used in RFC 2613 RFC 2641 RFC 2643 RFC 2674 RFC 3518 RFC 3619 RFC 4363 RFC 4554 RFC 4562 RFC 4665 RFC 4675 RFC 4719 RFC 4852 RFC 4968 RFC 5309 RFC 5517 RFC 5556 RFC 5603 RFC 5777 RFC 5828 RFC 6136 RFC 6165 RFC 6246 RFC 6325 and 20 more
- Vocoder
A speech coder that turns voice into a small set of parameters that can be sent at a low bitrate, then rebuilds speech from them at the other end.
Plain language A speech coder turning voice into a small set of parameters for low bitrate transmission.
Used in RFC 807 RFC 3558 RFC 3625 RFC 3952 RFC 4788 RFC 8130 RFC 8817
- Voice Activity Detection
A feature that detects when a speaker has stopped talking, used to reduce the amount of data sent during silence periods.
Plain language A feature detecting when a speaker has stopped talking to reduce data sent during silence.
Used in RFC 3267 RFC 3389 RFC 5087 RFC 5574 RFC 6562 RFC 6716
- VoIP
Voice over IP. Phone calls carried as packets over an IP network instead of a traditional telephone circuit.
Plain language Phone calls carried as packets over an IP network instead of a traditional telephone circuit.
Used in RFC 2543 RFC 2705 RFC 2719 RFC 2805 RFC 2824 RFC 2871 RFC 2995 RFC 3015 RFC 3136 RFC 3219 RFC 3261 RFC 3326 RFC 3372 RFC 3389 RFC 3398 RFC 3432 RFC 3435 RFC 3495 RFC 3508 RFC 3523 RFC 3525 RFC 3603 RFC 3611 RFC 3660 and 73 more
- Voucher
A signed statement from a manufacturer's signing service telling a new device the cryptographic identity of the domain it should trust. It is how a device learns its owner.
Plain language A signed statement from a manufacturer telling a new device the cryptographic identity to trust.
Used in RFC 3506 RFC 4153 RFC 8366 RFC 8572 RFC 8995 RFC 9733
- VPLS
Virtual Private LAN Service. A provider service in which customer devices at different sites appear to be connected by a single LAN.
Plain language A provider service where customer devices at different sites appear connected by a single LAN.
Used in RFC 2764 RFC 4026 RFC 4665 RFC 6074 RFC 6136 RFC 7080 RFC 7117 RFC 7152 RFC 7209 RFC 7257 RFC 7309 RFC 7387 RFC 7439 RFC 7623 RFC 7769 RFC 7796 RFC 8466
- VPWS
A Virtual Private Wire Service is a point-to-point Layer 2 circuit that joins two customer edge devices. The provider carries it over a packet switched network as a logical Layer 2 circuit, usually as a pseudowire.
Plain language A private link that joins exactly two sites. It behaves like a straight cable between them, so only the two ends can exchange traffic.
- VRF
A VPN Routing and Forwarding table, a separate routing table kept on a router for one VPN. A single router can hold several VRFs at once.
Plain language A VPN Routing and Forwarding table, a separate routing table kept on a router for one VPN.
Used in RFC 4364 RFC 4365 RFC 4382 RFC 4577 RFC 4659 RFC 4684 RFC 5824 RFC 6016 RFC 6037 RFC 6368 RFC 6514 RFC 6565 RFC 7024 RFC 7246 RFC 7611 RFC 7674 RFC 7900 RFC 7956 RFC 8049 RFC 8299 RFC 8368 RFC 8529 RFC 8994 RFC 9069 and 2 more
- VRRP
The Virtual Router Redundancy Protocol lets routers back each other up so that a backup takes over when the master fails. Version 3 covers both IPv4 and IPv6 and is defined in RFC 5798.
Plain language A protocol letting routers back each other up so a backup takes over when the master fails.
- VTIMEZONE
The iCalendar component that describes a time zone, with STANDARD and DAYLIGHT sub-components giving the offsets and when they change.
Plain language An iCalendar component describing a time zone with offset and daylight saving information.
Used in RFC 2445 RFC 4791 RFC 4833 RFC 5545 RFC 5546 RFC 7529 RFC 7808 RFC 7809 RFC 7953 RFC 8984
- Vulnerability disclosure
The process by which someone who finds a security flaw reports it to the party responsible for the affected product or service, so that it can be fixed and, usually, announced.
Plain language Reporting a security flaw to the responsible party so it can be fixed.
Used in RFC 1135 RFC 1244 RFC 2350 RFC 7495 RFC 8953 RFC 9116 RFC 9267