FEC—Forwarding Equivalence Class. A set of packets that can be handled equivalently for forwarding purposes and are thus suitable for binding to a single label. Examples include the set of packets destined for one address prefix and any flow.
flow—Generally, a set of packets traveling between a pair of hosts, or a pair of transport protocol ports on a pair of hosts. For example, packets with the same source address, source port, destination address, and destination port might be considered a flow.
A flow is also a stream of data traveling between two endpoints across a network (for example, from one LAN station to another). Multiple flows can be transmitted on a single circuit.
fragmentation—Process of breaking a packet into smaller units when transmitting over a network medium that cannot support the original size of the packet.
ICMP— Internet Control Message Protocol. A network layer Internet protocol that reports errors and provides other information relevant to IP packet processing. It is documented in RFC 792.
LFIB—label forwarding information base. A data structure and way of managing forwarding in which destinations and incoming labels are associated with outgoing interfaces and labels.
localhost—A name that represents the host name of a device. The localhost uses the reserved loopback IP address 127.0.0.1.
LSP—label switched path. A connection between two devices that uses MPLS to carry the packets.
LSPV—Label Switched Path Verification. An LSP Ping subprocess that encodes and decodes MPLS echo requests and replies; interfaces with IP, MPLS, and AToM switching for sending and receiving MPLS echo requests and replies; and, at the MPLS echo request originator device, maintains a database of outstanding echo requests for which echo responses have not been received.
MPLS router alert label—An MPLS label of 1. An MPLS packet with a router alert label is redirected by the device to the Route Processor (PR) processing level for handling. This allows these packets to bypass any forwarding failures in hardware routing tables.
MRU—maximum receive unit. Maximum size, in bytes, of a labeled packet that can be forwarded through an LSP.
MTU—maximum transmission unit. Maximum packet size, in bytes, that a particular interface can handle.
punt—Redirect packets with a router alert from the line card or interface to Route Processor (RP) level processing for handling.
PW—pseudowire. A mechanism that carries the essential elements of an emulated circuit from one provider edge (PE) device to another PE device over a packet-switched network.
RP—Route Processor. Processor module in the Cisco 7000 series routers that contains the CPU, system software, and most of the memory components that are used in the device. It is sometimes called a supervisory processor.
RSVP—Resource Reservation Protocol. A protocol that supports the reservation of resources across an IP network. Applications running on IP end systems can use RSVP to indicate to other nodes the nature (bandwidth, jitter, maximum burst, and so on) of the packet streams they want to receive. RSVP depends on IPv6. Is is also known as Resource Reservation Setup Protocol.
UDP—User Datagram Protocol. Connectionless transport layer protocol in the TCP/IP protocol stack. UDP is a simple protocol that exchanges datagrams without acknowledgments or guaranteed delivery, requiring that error processing and retransmission be handled by other protocols. UDP is defined in RFC 768.