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Local Area Networks

They are the means of sharing files and common resources such as printers. They provide access to wide area networks, host computers, and servers.

LANs started out as narrow-range systems, but the enterprise network of today has evolved into a network of interconnected LANs.

By definition, a LAN is a network dedicated to a single organization, limited in range, and connected by a common communication technology.

local area network technology

A LAN has the following characteristics:

High speed A restricted range. share a common transmission

medium. A network operating system (NOS)

NIC has the following functions:

Physical interface to the transmission medium.

Monitors the busy/idle status of the network.

Buffers/device to the speed of the network

Transmitted data stream into frames for transmission

On the networkErrors and collisions

LANs can be classified according to four cruteria:

o Topologyo Access methodo Modulation methodo Transmission medium

Topology

Access Methods

LAN access methods: contention or noncontention.

CSMA/CD

Modulation Methods

a) In the first, baseband,b) other method, broadband,

broadband

Transmission Media

All of the transmission media used in other networks:

twisted pair wire coaxialcable fiber optics radio, and infrared

802.1 Overview document containing the reference model, and glossary

802.1b Standard for LAN/WAN management, Virtual bridged LANs

802.2 Logical link control 802.3 100 mb/s contention bus standard 10/100-Base-T 802.3 Gigabit Ethernet, Power over Ethernet (FOIRL) Full duplex

Ethernet 802.4 Token bus standard 802.5 Token ring standard 4 Mbps over unshielded twisted pair 802.6 Metropolitan area network DQDB 802.7 Broadband LAN recommended practices 802.8 Fiber optic contention network practices 802.9 Integrated voice and data LAN 802.10 Interoperable LAN Security 802.11 Wireless LAN standard 802.12 Contention bus standard 100VG AnyLAN

802.3 Ethernet standard

802.3 ETHERNET STANDARDS

Fast Ethernet LAN Traffic Prioritization Gigabit Ethernet 10 Gigabit Ethernet Power over Ethernet (PoE)

Power over Ethernet (PoE)

Class 0: (the default, when a device’s class is unknown) 15.4 W

Class 1: 4 W Class 2: 7 W Class 3: 15.4 W

LAN ARCHITECTURES

Bridging and Switching

Switching Technology

NETWORK OPERATING SYSTEMS Application program to the computers

operating system Information transfer between the

network and the server Manage security on the network Directly attached to the users personal

computers. Network administrator can manage the

network.

Peer-to-Peer Networks

inherent in Microsoft’s Windows printers, disk etc…

a printer, data or print job, others are attached to their computer all files are storedon a server, user’s disk, modify and save it to their

own hard disk.

LAN APPLICATION ISSUES

Security Fault Tolerance Network Management Internetworking Infrastructure Planning Backbone Architecture Network Speed and Throughput

Thank you for your attention.