Psion Teklogix 9160 G2 Manual de usuario descargar pdf (Pagina 413)

Appendix D: Glossary

Network Address

Psion Teklogix 9160 G2 Wireless Gateway User Manual D-63

maps all internal IP addresses in outbound requests to its own address and converts all

inbound requests to the correct internal host.

NAT serves three main purposes: it provides security by obscurity by hiding internal IP

addresses, enables the use of a wide range of internal IP addresses without fear of conflict

with the addresses used by other organizations, and it allows the use of a single Internet

connection.

Network Address

See IP Address.

NIC

A Network Interface Card is an adaptor or expansion board inserted into a computer to

provide a physical connection to a network. Most NICs are designed for a particular type of

network, protocol, and media, for example, Ethernet or wireless.

NTP

The Network Time Protocol assures accurate synchronization of the system clocks in a

network of computers. NTP servers transmit Coordinated Universal Time (UTC, also

known as Greenwich Mean Time) to their client systems. An NTP client sends periodic time

requests to servers, using the returned time stamp to adjust its clock.

OSI

The Open Systems Interconnection (OSI) reference model is a framework for network

design. The OSI model consists of seven layers:

• Layer 1, the Physical layer, identifies the physical medium used for communication

between nodes. In the case of wireless networks, the physical medium is air, and radio

frequency (RF) waves are a components of the physical layer.

• Layer 2, the Data-Link layer, defines how data for transmission will be structured and

formatted, along with low-level protocols for communication and addressing. For

example, protocols such as CSMA/CA and components like MAC addresses, and

Frames are all defined and dealt with as a part of the Data-Link layer.

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Psion Teklogix 9160 G2 Manual de usuario Pagina 413