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Protocol Independent Multicast sparse mode: PIM SM utilizes the
unicast route table and relies on the shared root distribution architecture for
multicast data forwarding.
PIM sparse-dense mode
An interface configuration that allows the inter-
face to choose the method of PIM operation.
packet Internet groper: A Unix-based Internet diagnostic tool, con-
sisting of a message sent to test the accessibility of a particular device on the
IP network. The acronym (from which the "full name" was formed) reflects
the underlying metaphor of submarine sonar. Just as the sonar operator
sends out a signal and waits to hear it echo ("ping") back from a submerged
object, the network user can ping another node on the network and wait to
see if it responds.
pinhole congestion
Two links to the same remote network with equal
hops but with different bandwidths. Distance vector will try to load balance
and waste bandwidth.
Nearly synchronous, except that clocking comes from an
outside source instead of being embedded within the signal as in synchro-
nous transmissions.
Packet Level Protocol: Occasionally called X.25 Level 3 or X.25 Pro-
tocol, a Network layer protocol that is part of the X.25 stack.
Private Network-Network Interface: An ATM Forum specification
for offering topology data used for the calculation of paths through the net-
work, among switches and groups of switches. It is based on well-known
link-state routing procedures and allows for automatic configuration in net-
works whose addressing scheme is determined by the topology.
point-to-multipoint connection
In ATM, a communication path going
only one way, connecting a single system at the starting point, called the
"root node," to systems at multiple points of destination, called "leaves."
See also: point-to-point connection.
point-to-point connection
In ATM, a channel of communication that
can be directed either one way or two ways between two ATM end systems.
See also: point-to-multipoint connection.
Copyright ©2001 SYBEX , Inc., Alameda, CA