adjacency—A relationship formed between selected neighboring routers and end nodes for the purpose of exchanging routing information. Adjacency is based upon the use of a common media segment by the routers and nodes involved.
Forwarding—A Layer 3 switching technology. Cisco Express Forwarding can also refer to a central Cisco Express Forwarding mode, one of two modes of the Cisco Express Forwarding operation. Cisco Express Forwarding enables a Route Processor (RP) to perform express forwarding. Distributed Cisco Express Forwarding is the other mode of the Cisco Express Forwarding operation.
Forwarding—A mode of Cisco Express Forwarding switching in which line cards maintain identical copies of the forwarding information base (FIB) and adjacency tables. The line cards perform express forwarding between port adapters; this relieves the Route Processor from any involvement in the switching operation.
FIB—forwarding information base. A component of Cisco Express Forwarding that is conceptually similar to a routing table or information base. The router uses the FIB lookup table to make destination-based switching decisions during the Cisco Express Forwarding operation. The router maintains a mirror image of the forwarding information in an IP routing table.
IPC—interprocess communication. The mechanism that enables the distribution of Cisco Express Forwarding tables from the RP to the line card when the router is operating in distributed Cisco Express Forwarding mode.
LIB—label information base. A database used by a label switch router (LSR) to store labels learned from other LSRs, as well as labels assigned by the local LSR.
card—A general term for an interface processor that can be used in various Cisco products.
MPLS—Multiprotocol Label Switching. An industry standard for the forwarding of packets along normal routing paths (sometimes called MPLS hop-by-hop forwarding).
prefix—The network address portion of an IP address. A prefix is specified by a network and mask and is generally represented in the format network/mask. The mask indicates which bits are network bits. For example, 192.0.2.1/16 means that the first 16 bits of the IP address are masked, making them the network bits. The remaining bits are the host bits. In this example, the network number is 192.0.
RIB—Routing Information Base. A central repository of routes that contains Layer 3 reachability information and destination IP addresses or prefixes. The RIB is also known as the routing table.
RP—Route Processor. The processor module that contains the CPU, system software, and most of the memory components that are used in the router. It is sometimes called a supervisory processor.
VPN—Virtual Private Network. The result of a router configuration that enables IP traffic to use tunneling to travel securely over a public TCP/IP network.
—A Virtual Private Network (VPN) routing/forwarding instance. A VRF consists of an IP routing table, a derived forwarding 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 Provider Edge router.