Cisco OL-4387-02 Configuration Manual page 101

T
Connection-oriented transport layer protocol that provides reliable full-duplex data transmission. TCP
TCP
is part of the TCP/IP protocol stack.
A function of the PXF pipeline that determines whether a packet matches a list in a fixed, predictable
turbo access control
period of time, usually regardless of the number of entries in a list. Turbo ACLs enable more expedient
list
packet classification and access checks when the router is evaluating ACLs. The Turbo ACL feature
compiles the ACLs into a set of lookup tables, while maintaining the first match requirements. Packet
headers are used to access these tables in a small, fixed number of lookups, independently of the
existing number of ACL entries.
V
Virtual Circuit. Also referred to as Virtual Channel. Used in ATM applications. A link that seems and
VC
behaves like a dedicated point-to-point line or a system that delivers packets in sequence, as happens
on an actual point-to-point network. In reality, the data is delivered across a network via the most
appropriate route. The sending and receiving devices do not have to be aware of the options and the
route is chosen only when a message is sent. There is no pre-arrangement, so each virtual circuit exists
only for the duration of that one transmission.
Virtual channel identifier. A 16-bit field in the header of an ATM cell. The VCI, together with the VPI,
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 network VCL that a cell
needs to transmit on its way to its final destination. The function of the VCI is similar to that of the
DLCI in Frame Relay.
Virtual LAN. Group of devices on one or more LANs that are configured (using management software)
VLAN
so that they can communicate as if they were attached to the same wire, when in fact they are located
on a number of different LAN segments. Because VLANs are based on logical instead of physical
connections, they are extremely flexible.
Virtual path identifier. An 8-bit field in the header of an ATM cell. The VPI, together with the VCI, is
VPI
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
transmit on its way to its final destination. The function of the VPI is similar to that of the DLCI in
Frame Relay.
Virtual routing and forwarding instance. A VRF consists of an IP routing table, a derived forwarding
VRF
table, a set of interfaces that use the forwarding table, and a set of rules and routing protocols that
determine what goes into the forwarding table. In general, a VRF includes the routing information that
defines a customer VPN site that is attached to a PE router.
Vendor-Specific Attribute. An attribute that has been implemented by a particular vendor. It uses the
VSA
attribute Vendor-Specific to encapsulate the resulting AV pair: essentially, Vendor-Specific =
protocol:attribute = value.
OL-4387-02
Cisco 10000 Series Router Service Selection Gateway Configuration Guide
Glossary
GL-5