Chapter 6

LAN vs. WAN

Explore "How Stuff Works" Site for a Quick Overview

Local Area Networks (LAN)

This is designed for a small geographic area.  Each device on the LAN is called a node.  LANs are connected in a peer-to-peer connection, which means they can share and transfer information.  Each computer needs a Network Interface Card (NIC) to connect to the network.  A Hub is used to connect several computers together on a network.  If there is a larger network, the network administrator may want to consider a Client/Server network.  These are primarily used in a business environment.

Wide Are Network (WAN) 

This is a network covering a very wide geographic area.  Most WANs are corporately owned.

Physical Topologies

Bus - Connects all nodes on Peer-to-Peer LAN.  

Ring - Connects each node to the next

Star - Connects each node to a central device

Access Methods

Logical Topology - the method the information is transmitted between nodes

Ethernet - Network access method where a node that is transmitting data checks to see if other nodes are sending information   

Token Ring - Moves information in packets around in a clockwise fashion

Transmission Media

Infrared (IR) Transmissions - uses infrared light waves as a transmission method

Radio Frequency Transmissions - Uses Broadcast Radio Waves to transmit data

Bluetooth - Short range RF Technology that sends and receives wireless transmission between devices.  

Wirless LAN (WLAN)

Uses wireless transmission to connect devices.


Twisted Pair Cable - insulated copper wires twisted and paired and enclosed in plastic covering

Fiber-optic Cable - contains glass fibers surrounded by a layer of glass cladding and a protective outer jacket.  Is used for voice, video, and data transmission over long distances.

HUBS - Used to connec t multiple nodes

Bridges - an intelligent connectivity device that with one input port and one output port that connects two segments on the same LAN or two separate LANs.

Data Switches - an intelligent device that also interprets MAC addresses and filters and forwards packets to other network segments.

Routers - an intelligent device with multiple ports.  A router can determine the best route for a packet to take.

Network Service Providers (NSPs) - provide the public and private network infrastructure for the Internet.

Internet Exchange Points - A physical infrastructure that allows ISPs to communicate among their networks.

Metropolitan Area Exchange(MAE) - High speed Ethernet connection within a metropolitan area.

Peering-  the exchange of Internet traffic and router information between NSPs and ISPs at an exchange point.

TCP/IP - Tranmission Control Protocol / Internet Protocol is the set of standard Internet protocols on which the communications across the Internet and many privately held networks rely.

IP Address - Individual and unique identifier on the internet.  Similar in concept to a phone number.

Domain Name System (DNS) - A method to give IP Addresses more meaning to users

DNS Registration - Alows private companies to handle the registration of the domain names.

Selecting a Domain Name - This name must be unique and at the same time meaningful to you and your customers.

Location Based Services - A wireless service offered to customers based on their physical location.

GPS - Global Positioning System is a navigation system

Internet Telephony - Uses IP packet-switching technologies to make telephone calls.

VoIP - Voice over IP is a popular option for hom,e telephone service because of reduced costs.

Virtual Meetings - Allows collaboration between participants via the internet.

Web Conferencing - Uses real time video and audio.

External network security threats - Those that originate from outside the network, such as natural disasters, hackers, viruses, worms, and Trojan horses. The 

Network Security Audits - Conducted by third-party auditing firms, to expose network vulnerabilities. Employees' inappropriate use of Internet access can increase a company's potential liabilities and network security risks.