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Glossary

NLSP

NetWare Link Services Protocol: Novell's link-state routing pro-

tocol, based on the IS-IS model.

NMP

Network Management Processor: A Catalyst 5000 switch processor

module used to control and monitor the switch.

node address

Used to identify a specific device in an internetwork. Can be

a hardware address, which is burned into the network interface card or a log-
ical network address, which an administrator or server assigns to the node.

nondesignated port

The Spanning Tree Protocol tells a port on a layer 2

switch to stop transmitting and creating a network loop. Only designated
ports can send frames.

non-stub area

In OSPF, a resource-consuming area carrying a default

route, intra-area routes, interarea routes, static routes, and external routes.
Non-stub areas are the only areas that can have virtual links configured
across them and exclusively contain an anonymous system boundary router
(ASBR). Compare with: stub area. See also: ASBR and OSPF.

NRZ

Nonreturn to Zero: One of several encoding schemes for transmitting

digital data. NRZ signals sustain constant levels of voltage with no signal
shifting (no return to zero-voltage level) during a bit interval. If there is a
series of bits with the same value (1 or 0), there will be no state change. The
signal is not self-clocking. See also: NRZI.

NRZI

Nonreturn to Zero Inverted: One of several encoding schemes for

transmitting digital data. A transition in voltage level (either from high to
low or vice-versa) at the beginning of a bit interval is interpreted as a value
of 1; the absence of a transition is interpreted as a 0. Thus, the voltage
assigned to each value is continually inverted. NRZI signals are not self-
clocking. See also: NRZ.

NT1

network termination 1: Is an ISDN designation to devices that under-

stand ISDN standards.

NT2

network termination 2: Is an ISDN designation to devices that do

not understand ISDN standards. To use a NT2, you must use a terminal
adapter (TA).

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