Symmetricom S100 manual Lan, Ldap, MD5, Mib, Mtbf

SyncServer S100

L1 Band, L2 Band

Each Navstar GPS satellite currently transmits in two dedicated frequency bands: L1 and L2, which is centered on 1227.6 MHz. L1 carries one encrypted signal, as does L2, both being reserved for the military. L1 also carries one unencrypted signal, for civilian use.

LAN

Local area network (LAN): A data communications system that (a) lies within a limited spatial area, (b) has a specific user group, (c) has a specific topology, and (d) is not a public switched telecommunications network, but may be connected to one. Note 1: LANs are usually restricted to relatively small areas, such as rooms, buildings, ships, and aircraft. Note 2: An interconnection of LANs within a limited geographical area, such as a military base, is commonly referred to as a campus area network. An interconnection of LANs over a city-wide geographical area is commonly called a metropolitan area network (MAN). An interconnection of LANs over large geographical areas, such as nationwide, is commonly called a wide area network (WAN). Note 3: LANs are not subject to public telecommunications regulations.

LDAP

The Lightweight Directory Access Protocol is the standard Internet protocol for accessing directory servers over a network.

Leap Seconds

Today’s scientists and engineers have perfected clocks based on a resonance in Cesium atoms to an accuracy of better than one part in 10 trillion. These clocks keep pace with each other to within one two- or three-millionth of a second over a year’s time. The earth, on the other hand, can accumulate nearly a full second of error during a given year. To keep coordinated with the rotation of the earth, this error is added to (or deleted from) UTC time as a leap second, on the last day of the June or December in that year.

MD5

An algorithm for creating a cryptographic hash (or “fingerprint”) of a message or of data.

Message Authentication Code (MAC)

A MAC is a function that takes a variable length input and a key to produce a fixed-length output.

Message Digest

The hash of a message.

See also: Hash

MIB

Management Information Base, a database on the network that tracks, records, and corrects performance for each device on the network.

MTBF

Mean Time Between Failure, a measure of reliability. The longer the time span between failures, the more reliable the device.

128 S100 User Guide – Rev. D – June 2005