What is Computer Network ?

 In its simplest form, a network is nothing more than “two connected computers sharing resources with one another.”

• It is composed of two main aspects:

Physical Connection (wires, cables, wireless media) o Logical Connection (data transporting across the physical media)

Types of Computer Networks (by Size)

• Personal Area Network (PAN) 

• Local Area Network (LAN) 

• Wireless Local Area Network (WLAN) 

• Campus Area Network (CAN) • Metropolitan Area Network (MAN) • Wide Area Network (WAN)

Personal Area Network (PAN) 

• Ultra-small networks used for personal use to share data from one device to another.

• Can be wired (PAN) or wireless (WPAN):U USBB

Bluetooth

NFC 

ANT+

 • Examples:

Smart Phone to Laptop 

Smart Watch 

Smart Phone 

SmartPhone Hands-Free Car Calling 

Heart Rate Monitor 

Smart Phone

Local Area Network (LAN) 

• A computer network within a small geographical area, such as a single room, building or group of buildings.

• Considered to be self-contained:

 All devices are directly connected via cables and/or short-range wireless technology.

 Doesn’t require a leased telecommunications line from an Internet Service Provider (ISP).

• Examples:

     Home Network 

     Small Business or Office Network

Wireless Local Area Network (WLAN)

• A LAN that’s dependent on wireless connectivity or one that extends a traditional wired LAN to a wireless LAN.

• Most home networks are WLANs.

Campus Area Network (CAN) 

• A computer network of multiple interconnected LANs in a limited geographical area, such as a corporate business park, government agency, or university campus.

• Typically owned or used by a single entity.

Metropolitan Area Network (MAN)

 • A computer network that interconnects users with computer resources in a city.

• Larger than a campus area network, but smaller than a wide area network.

Wide Area Network (WAN)

 • A computer network that extends over a large geographical distance, typically multiple cities and countries.

• WANs connect geographically distant LANs.

• Typically use leased telecommunications lines from ISPs.

• Examples:

 The Internet o Corporate Offices in Different States

Why Build a Computer Network?

• Before computer networks, people sent and received information by hand, using the postal service. This is slow and can be unreliable.

• Computer networks enable faster, more efficient modes of communication, i.e., email, video conferencing, etc.

• Computer networks and the sharing of electronic data encourage the use of standard policies and procedures.

• Computer networks provide backup and recovery support for our data, i.e., redundancy.

• Computer networks lead to cost savings.

Peer-to-Peer Connection

 • All computers on the network are peers 

• No dedicated servers

 • There’s no centralized control over shared resources 

• Any device can share its resources as it pleases

 • All computers can act as either a client or a server

 • Easy to set-up, and common in homes and small businesses 

Client-Server

• The network is composed of client and servers

 • Servers provide resources

 • Clients receive resources

 • Servers provide centralized control over network resources (files, printers, etc.)

 • Centralizes user accounts, security, and access controls to simplify network administration

 • More difficult to setup and requires an IT administrator