Glossary
MD5 Message-Digest Algorithm
An algorithm that is used to create digital signatures. It is intended for use with 32 bit
machines and is safer than the MD4 alg orithm, which has bee n broken. M D5 is a
one-way hash function, meaning that it takes a message and converts it into a fixed
string of digits, also called a message digest.
Multicast Switching
A process whereby the switch filters incoming multicast frames for services for
which no attached host has registered, or forwards them to all p orts con ta ined w ithin
the designated multicast VLAN group.
Network Time Protocol (NTP)
NTP provides the mechanisms to synchronize time across the network. The time
servers operate in a hierarchical-master-slave configuration in order to synchronize
local clocks within the subnet and to national time standar ds via wire or radio.
Open Shortest Path First (OSPF)
OSPF is a link-state routing protocol that functions bett er ov er a large r netw ork s uch
as the Internet, as opposed to distance-vector routing protocols such as RIP. It
includes features such as unlimited hop count, authentication of routing updates,
and Variable Length Subnet Masks (VLSM).
Out-of-Band Management
Management of the network from a station not attached to the network .
Port Authentication
See IEEE 802.1X.
Port Mirroring
A method whereby data on a target port is mirrore d to a monit or port for
troubleshooting with a logic analyzer or RMON probe. This allows data o n th e target
port to be studied unobstructively.
Port Trunk
Defines a network link aggregation and trunking method which sp ecifies how t o
create a single high-speed logical link that combines seve ra l lowe r-sp eed p hy sical
links.
Private VLANs
Private VLANs provide port-based security and isolation between ports within the
assigned VLAN. Data traffic on downlink ports can only be forwarded to, and from,
uplink ports.
Glossary-5