User guide

Glossary 437
Mask
A filter that includes or excludes certain values, for
example parts of an IP address.
For example, Unit 2 is inserted in the first minute of
a ten-minute cycle, and Unit 1 is inserted in fifth
minute of the same cycle, the units are considered
the same age.
MD5
Message Digest 5. An algorithm that produces a 128-
bit hash. MD5 is a variation of MD4, and increases
MD4 security. MD5 verifies the integrity of the
communication, authenticates the origin of the
communication.
MDI
Media Dependent Interface. A cable used for end
stations.
MDIX
Media Dependent Interface with Crossover (MDIX).
A cable used for hubs and switches.
MIB
Management Information Base. MIBs contain
information describing specific aspects of network
components.
Multicast
Transmits copies of a single packet to multiple ports.
N
NA
Neighbor Advertisement.
ND
Neighbor Discovery.
NS
Neighbor Solicitation.
NMS
Network Management System. An interface that
provides a method of managing a system.
Node
A network connection endpoint or a common
junction for multiple network lines. Nodes include:
• Processors
• Controllers
• Workstations
O
OID
Object Identifier. Used by SNMP to identify
managed objects. In the SNMP Manager/ Agent
network management paradigm, each managed
object must have an OID to identify it.
P
Packets
Blocks of information for transmission in packet
switched systems.
PDU
Protocol Data Unit. A data unit specified in a layer
protocol consisting of protocol control information
and layer user data.