ECMP —equal-cost multipath. Multiple routing paths of equal cost that may be used for packet forwarding.
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 the packets in any flow.
flow —A set of packets traveling between a pair of hosts, or between 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.
localhost —A name that represents the host router (device). The localhost uses the reserved loopback IP address 127.0.0.1.
LSP —label switched path. A connection between two routers in which Multiprotocol Label Switching (MPLS) forwards the packets.
LSPV —Label Switched Path Verification. An LSP ping subprocess. It encodes and decodes Multiprotocol Label Switching (MPLS) echo requests and replies, and it interfaces with IP, MPLS, and AToM switching for sending and receiving MPLS echo requests and replies. At the MPLS echo request originator router, LSPV maintains a database of outstanding echo requests for which echo responses have not been received.
MPLS router alert label —An Multiprotocol Label Switching (MPLS) label of 1. An MPLS packet with a router alert label is redirected by the router to the Route Processor (PR) processing level for handling. This allows these packets to bypass any forwarding failures in hardware routing tables.
OAM —Operation, Administration, and Management.
punt —Redirect packets with a router alert from the line card or interface to Route Processor (RP) level processing for handling.
RP —Route Processor. The processor module contains the CPU, system software, and most of the memory components that are used in the router.
TTL —time-to-live. A parameter you can set that indicates the maximum number of hops a packet should take to reach its destination.
TLV —type, length, values. A block of information included in a Cisco Discovery Protocol address.
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, so error processing and retransmission must be handled by other protocols. UDP is defined in RFC 768.
XDR —eXternal Data Representation. Standard for machine-independent data structures developed by Sun Microsystems. Used to transport messages between the Route Processor (RP) and the line card.