LAN

Dr. Yan Quan LiuILS SCSU

ILS 501Unit 10

04/19/23 ILS 501 / Dr. Liu, SCSU 2

What is LAN (local area network)?

A group of computers dispersed over a local area and connected by a communications link that enables any device to interact with any other on the network.

04/19/23 ILS 501 / Dr. Liu, SCSU 3

Types:

Client-server LAN Peer-to-peer LAN

04/19/23 ILS 501 / Dr. Liu, SCSU 4

Types of LANsClient/server LAN - Clients -

microcomputers that request data

Server - a powerful microcomputer that supplies data andmanagesshared devices

04/19/23 ILS 501 / Dr. Liu, SCSU 5

Types of LANsPeer-to-peer LAN - all microcomputers on the network communicate directly with one another without relying on a server

04/19/23 ILS 501 / Dr. Liu, SCSU 6

Components of LANsConnection or cabling system

Microcomputers with network interface cards

Network OS

Other shared devices

Routers, bridges, and gateways

Hub

04/19/23 ILS 501 / Dr. Liu, SCSU 7

Wireless local area networks (WLANs)

A wireless LAN (or WLAN, for wireless local area network, sometimes referred to as LAWN, for local area wireless network) is one in which a mobile user can connect to a local area network (LAN) through a wireless (radio) connection

04/19/23 ILS 501 / Dr. Liu, SCSU 8

802.11 tech for WLANs

802.11 is an evolving family of specifications for wireless local area networks (WLANs) developed by a working group of the Institute of Electrical and Electronics Engineers (IEEE). There are several specifications in the family and new ones are occasionally added.

04/19/23 ILS 501 / Dr. Liu, SCSU 9

802.11 tech for WLANs

802.11g 30 MB/s 802.11n 300 MB/s

802 Standard comprises a family of networking standards that cover the physical layer specifications of technologies from Ethernet to wireless

04/19/23 ILS 501 / Dr. Liu, SCSU 10

Access Point

"In a wireless local area network ( WLAN ), an access point is a station that transmits and receives data (sometimes referred to as a transceiver). An access point connects users to other users within the network and ..."

04/19/23 ILS 501 / Dr. Liu, SCSU 11

What are common network interface devices?

04/19/23 ILS 501 / Dr. Liu, SCSU 12

Local area network technology-

Network interface devices

Common interface drivers/receivers connecting networks are: Bridge Router Gateway Firewall

04/19/23 ILS 501 / Dr. Liu, SCSU 13

Network interface devices—

Bridge

A bridge is a product that connects a local area network to another local area network that uses the same protocol (for example, Ethernet)

04/19/23 ILS 501 / Dr. Liu, SCSU 14

Network interface devices—

Router

A router is a device or software in a computer, that determines the next network point to which a packet should be forwarded toward its destination.

The router is connected to networks with different operating systems.

04/19/23 ILS 501 / Dr. Liu, SCSU 15

Network interface devices—

Gateway

A gateway is a network point that acts as an entrance to another network. It performs all functions of bridges and routers but slower in terms of speed than those two.

04/19/23 ILS 501 / Dr. Liu, SCSU 16

Network interface devices—

Firewall

A firewall is a set of related programs, located at a network gateway server, that protects the resources of a private network from all unauthorized users from other networks.

04/19/23 ILS 501 / Dr. Liu, SCSU 17

Ending notes:

Essential Questions

What does telecommunication mean? How is connection made to a network? What are the types and components of

communication channels? What does the future hold in relation to

telecommunications?

04/19/23 ILS 501 / Dr. Liu, SCSU 25

Quick Note on Network Setups

Simple Network Dialup

56k Modem plugged into phone line (1 computer)

Computer

DialupModem

PhoneOutlet

Note: Uses regular

phone cable

04/19/23 ILS 501 / Dr. Liu, SCSU 26

Quick Note on Network Setups

Simple Cable/Satellite Modem

Cable/DSL/Satellite Modem plugged into cable/DSL/satellite outlet (1 computer)

Charter and SBC/Yahoo are broadband Internet services

Computer

Cable/DSL/SatelliteModem

Cable/SatelliteOutlet

Note: Uses special Category 5 (Cat 5 RJ45)

Cable called patchcords

*Most network equipmenthas a speed of 100Mbit/s

04/19/23 ILS 501 / Dr. Liu, SCSU 27

Quick Note on Network Setups Cable/DSL/Satellite with Hub

Cable/DSL/Satellite Modem plugged into cable/DSL/satellite outlet

Requires 2 or more Internet Protocol (IP) connections (like 2 separate phone numbers)

Computer

Cable/DSLSatelliteModem

Cable/DSLSatelliteOutlet

Hub

Computer

04/19/23 ILS 501 / Dr. Liu, SCSU 28

Quick Note on Network Setups

Cable/DSL/Satellite with Router/Switch

Cable/DSL/Satellite Modem and Router/ Switch* plugged into cable/satellite outlet

Requires only 1 Internet Protocol (IP) connection (shares a phone number-saves $$)

Computer

Cable/DSLSatelliteOutlet

Router/Switch

Computer*Switches are smarter and faster than hubs

Cable/DSLSatelliteModem

04/19/23 ILS 501 / Dr. Liu, SCSU 29

Quick Note on Network Setups

Cable/Satellite with Wireless Router/Switch

Cable/Satellite Modem and wireless Router/Switch plugged into cable/satellite outlet

Requires wireless network cards. Wireless is more convenient but less secure than Cables

ComputerCable/

SatelliteModem

Cable/SatelliteOutlet

WirelessRouter/Switch

Computer

04/19/23 ILS 501 / Dr. Liu, SCSU 30

Quick Note on Network Setups

Firewalls

Firewalls are like the firewall in your car, which keep the heat and noise of the engine outside the passenger compartment

Computer Firewalls are used to keep unwanted Internet users from accessing your network

Once online, you are vulnerable w/o a firewall BlackIce is an example of firewall software

Computer

Cable/SatelliteModem

Cable/SatelliteOutlet

Router/Switch

& Firewall

Firewall

04/19/23 ILS 501 / Dr. Liu, SCSU 31

Quick Note on Networks

Firewalls

Computer Firewalls work like Caller ID You set up the rules of who can “call”

you Unrecognized callers are either denied,

or asked for a passwordNOTE: Some software, like PCAnywhere

and SQL Server require the firewall to specially configured

04/19/23 ILS 501 / Dr. Liu, SCSU 32

Questions?