Topic 2: Data Communication and the Internet

Network

• consists of 2 or more computers connected together, and they can communicate and share resources (e.g. information)

• Unshielded Twisted-Pair (UTP) Cables

• Shielded Twisted-Pair (STP) Cables

• Coaxial Cables

• Fiber-Optic Cables

Wired Technologies

• Terrestrial Microwaves

• Satellites Communication

• Cellular Networks

• Bluetooth

Wireless Technologies

• Local Area Network (LAN)

• Metropolitan Area Network (MAN)

• Wide Area Network (WAN)

• Personal Area Network (PAN)

Based on Network Size

• Linear Bus Topology

• Star Topology

• Ring Topology

• Hybrid Topology

Types of Network Topologies

Unshielded Twisted-Pair (UTP) Cables

• Typically wrapped inside a plastic cover (for mechanical protection)

• A cable with 5 unshielded twisted pairs of wires

Shielded Twisted-Pair (STP) Cables

• this cables are similar to UTP cables, except there is a metal foil or braided-metal-mesh cover that encases each pair of insulated wires

Coaxial Cables

• is a type of wired transmission medium used to transmit data, voice, and video signals.

Examples:

• Cable TV

• Early Ethernet Networks

• CCTV systems

Sheath

• Plastic covering and protects the cable physically

Insulation (PVC, Teflon)

• it protects the core.

• It also keeps the core separate from the braided shield.

Conducting Core

carries electromagnetic signals.

• Categorized into two types: single -core coaxial cable and

multi-core coaxial cable.

Braided Shielding

• This shield protects signals from external interference and noise.

• This shield is built from the same metal that is used to build the core.

Fiber-Optic Cables

• It is technologically-advanced as compared to the twisted-pair wire and coaxial cable.

• strands are extremely thin, no thicker than a human hair.

• Instead of transmitting frequencies, this cable transmits pulsating beams of light.

• Since light travels faster than electricity, this cables can carry a greater volume of data.

• Not flexible and expensive.

Terrestrial Microwaves

• A wireless communication signals that travel through the atmosphere using microwave frequencies and are transmitted between ground-based stations.

Satellites Communication

• is a type of wireless communication where signals are transmitted to a satellite in space, and the satellite relays the signal back to Earth.

Examples:

• Satellite TV (e.g., Cignal TV)

• GPS navigation

• Weather forecasting

• International phone calls

• Some rural internet services

Cellular Networks

• is a wireless communication system that divides a large geographic area into smaller areas called cells, each served by a base station (cell tower).

Bluetooth

• A short range wireless technology. Operate at approx. 1Mbps with range from 10 to 100 meters.

• is an open wireless protocol for data exchange over short distances.

Local Area Network (LAN)

• Small network, short distance

• A room, a floor, a building

⚬ Limited by no. of computers and distance covered

⚬ Usually one kind of technology throughout the LAN

• Serve a department within an organization

⚬ Network inside the Student Computer Room

⚬ Network inside your home

Wide Area Network (WAN)

• A network that uses long-range telecommunication links to connect 2 or more LANs/computers housed in different places far apart.

• is a computer network that covers a broad area (i.e. any network whose communications links cross metropolitan, regional, or national boundaries.

• The largest and most well-known example of a this network is the Internet.

Personal Area Network (PAN)

• A short-range, small-scale computer network used to interconnect personal devices like smartphones, laptops, and wearables, typically within a 10-meter radius.

• They can be wired (USB) or wireless, enabling data transfer, device synchronization, and internet access.

Network’s Topology

• refers to the physical connection of wires that connect the nodes of the network.

Linear Bus Topology

• is a type of network topology in which all devices are connected to a single cable called a "bus."’

• Simple and low-cost

• The data is transmitted as a broadcast to all devices connected to the bus. Each device on the network has a unique address, and a device will only accept the data if the destination address matches its own. If does not match, the device will simply ignore the transmitted data.

• Only one computer can send messages at a time.

Star Topology

• the server, nodes and other devices are connected to a central hub. All data from the source node must first pass through the central hub before it can reach the target node.

• In addition, a broken down node will not cause the whole system to break down. However, if a hub is broken, the whole network is lost.

• Two or more computers may send message at the same time.

Hybrid Topology

• In this topology, the other types of topologies are combined to form a combination network topology.

• are usually used to connect different floors or rooms of a building.

The Internet

• is a world-wide collection of computer networks.

• Individuals and organizations on a network connected to the internet can communicate with and find information on other computer networks that are also connected to the internet.

Electronic Mail

• is one of the primary uses of the internet.

• allows one user to send a text-based message to another.

File Transfer Protocol

• is a method for transferring files from one computer on the Internet to another.

World Wide Web Servers

• takes access a step further, providing a hypertext interface.

• Users can access other text, graphic, sound, and movie resources by pointing and clicking highlighted words or pictures, and can download the information being accessed.

Web Pages

• The WWW consists of information organized into thousands of pages stored in computers physically located throughout the world.

Web Browsers

• World Wide Web pages are accessed using client browser like Google Chrome, Safari, and others.

Hypertext

• allows you to progress or “branch” to other pages of information of interest or to jump backward and forward along the path you have take in your browsing.

Default Page

• known as home, the page of information your browser displays when started.

Hypertext Markup Language (HTML)

• is the foundation of the World Wide Web.

• All documents, or pages on the Web are linked together in hypertext architecture.

• Documents on the Web are formatted

Uniform Resource Locator (URL)

• every Web page has a unique identifier called WWW browser

Example:

• http://www.bicol-u.edu.ph

Transmission Control Protocol (TCP)

• The standard data transmission protocol for the internet.

Internet Protocol

• is a system used to connect the various computers within the internet.

• Every computer connected to the internet has its own IP number.

• An IP number is actually four different numbers, all separated by period.

Example:

• 192.168.0.1

Domain Names

• is an identification label that defines a realm of administrative autonomy, authority, or control in the internet.

• are hostnames that identify Internet Protocol (IP) resources such as web sites