User Manual

Glossary
M40 Internet Router Hardware Guide
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PIM Protocol Independent Multicast. A protocol-independent multicast routing protocol. PIM
Sparse Mode routes to multicast groups that might span wide-area and interdomain
internets. PIM Dense Mode is a flood-and-prune protocol.
PLP Packet Loss Priority.
policing Applying rate limits on bandwidth and burst size for traffic on a particular interface.
PPP Point-to-Point Protocol. Link-layer protocol that provides multiprotocol encapsulation. It is
used for link-layer and network-layer configuration.
preference Desirability of a route to become the active route. A route with a lower preference value is
more likely to become the active route. The preference is an arbitrary value in the range 0
through 255 that the routing protocol process uses to rank routes received from different
protocols, interfaces, or remote systems.
primary interface Router interface that packets go out when no interface name is specified and when the
destination address does not imply a particular outgoing interface.
Protocol-Independent
Multicast
See PIM.
provider edge router See PE router.
provider router Router in the service provider’s network that does not attach to a customer edge (CE) device.
Q
QoS Quality of service. Performance, such as transmission rates and error rates, of a
communications channel or system.
quality of service See QoS.
R
RADIUS Remote Authentication Dial-In User Service. Authentication method for validating users who
attempt to access the router using Telnet.
Random Early
Detection
See RED.
rate limiting See policing.
RBOC (Pronounced “are-bock”) Regional Bell operating company. Regional telephone companies
formed as a result of the divestiture of the Bell System.
RDRAM RAMBUS dynamic random access memory.
RED (Pronounced “red”) Random Early Detection. Gradual drop profile for a given class that is
used for congestion avoidance. RED tries to anticipate incipient congestion and reacts by
dropping a small percentage of packets from the head of the queue to ensure that a queue
never actually becomes congested.
Resource Reservation
Protocol
See RSVP.
RFC Request for Comments. Internet standard specifications published by the Internet
Engineering Task Force.