BIT Lecture 2 - Telecom & Networks

Computer Network

Is a system that connects computers and other devises through communications media so that data and information can be transmitted among them

Benefits of Networks?

• Shared Resources: Access data, programs, and devices instantly

• Communication: Internal messaging email, video confrencing

• Collaboration: Work together on documents, make edits, and comments

• Internet Access: Connect to information, cloud apps, and external networks

Bandwidth

Computer networks are becoming faster- that is their bandwidth is increasing. Refers to the transmission capacity of a network; it is stated in bits per second and ranges from narrowband (low capacity) to broadband (high capacity) 

Broadband 

The Federal Communications Commission (FCC) defines broadband as the transmission capacity of a communications medium faster than 25 megabits per second for download and 3 mps for upload. 

• The definition of broadband will continue to change to reflect greater transmission capacities in the future 

Personal Area Networks - Types of Computer Networks

Short-range, used for communication among devices close to one person. They can be wired or wireless

Local Area Network - Types of Computer Networks

Connects two or more devices in a limited region, usually within the same building, so that every device on the network can communicate with every other device

Large Networks - Types of computer Networks

Cover a metropolitan area

Wide Area Networks - Types of Computer Networks

Cover large geographical areas; they can span the entire planet and reach from Earth to Mars and beyond

Cable or Wireless Media

Use physical wires or cables to transmit data and information:

• Twisted-pair wire

• Coaxial Cable

• Fiber-Optic Cable

Broadcast or Wireless Media

Use radio signals that travel through the air to transmit data:

• most homes use wireless technology for both networking and internet access

• many businesses use it too

Internet Service Provider

• Large ISPs include Comcast, AT&T, Spectrum, and Verizon
  ⚬ ISPs connect to one another through network access points
  (NAPs) - exchange points for Internet traffic. They determine
  how traffic is routed.

• Internet kiosks have been placed in public places like libraries
  and airports for use by people who do not have their own
  computers.
  • Fiber-to-the-home is growing rapidly and involves connecting
  fiber-optic cable directly to individual homes (AT&T “Fiber”)

Addresses on the Internet

• Each computer on the internet has an assigned address that distinguishes it from all other computers

• IPv6 IP Address Scheme

Consists of 128 bits - eight groups of four digits separated by colons

IPv4 IP Address Scheme

Consists of 32 bits - sets of numbers in four parts, separated by dots

The World Wide Web

• Made up of websites/web pages that you can visit using a browser

• A way to access information on the Internet

• The WWW sits on top of the Internet, using the Internet’s infrastructure to fetch and display documents