LCP. Link Control Protocol. Protocol responsible for negotiating connection configuration parameters, authenticating peers on the link, determining whether a link is functioning properly, and terminating the link. Documented in RFC 1331.
LQM Link Quality Monitoring. Optional facility that lets PPP make policy decisions based on the observed quality of the link between peers. Documented in RFC 1333.
loopback test. Diagnostic procedure in which data is sent from a devices's output channel and directed back to its input chan- nel so that what was sent can be compared to what was received.
magic number. Random number generated by a router and included in packets it sends to other routers. If the router receives a packet with the same magic number it is using, the router sends and receives packets with new random numbers to determine if it is talking to itself.
MD5. A
metric. Distance, measured in the number of routers a packet must traverse, that a packet must travel to go from a router to a remote network. A route with a low metric is considered more efficient, and therefore preferable, to a route with a high metric. See hop count.
