Communications and Networks

Network Architecture and Network Strategies

100

What are all the topologies and strategies we learned this year?

Network Topology: Bus, Ring, star, tree and mesh 

Network Strategy: client/server and Peer-to-Peer

200

Describe any one network strategy.

Client/Server - Use central computers to coordinate and supply services to other nodes on the network.

Peer-to-Peer - nodes have equal authority and can act as both clients and servers. 

300

Describe any two network topologies.

Bus - Each device is connected to a common cable called a bus or backbone and all communications travel along this bus

Ring - Each device is connected to two other devices, forming a ring. When a message is sent, it is passed around the right until it reaches the intended destination

Star - Each device is connected directly to a central network, usually a switch. Whenever a node sends a message, it is routed to the switch, which then passes the message along to the intended recipient

Tree - Each device is connected to a central node, directly or through one or more other devices. The central node is connected to two or more subordinate nodes that in turn are connected to other subordinate nodes, and so forth, forming a treelike structure.

Mesh - This is the newest type of topology and does not use a specific physical layout. Requires that each node have more than one connection to the other nodes. The resulting pattern forms the appearance of a mesh.

400

One advantage and disadvantage of any network strategy.

Client/Server:

• Advantage of the client/server network strategy include:
  • Ability to handle very large networks efficiently.
  • Availability of powerful network management software to monitor and control network activities.
• Disadvantage of the client/server network strategy include:
  • Cost of installation and maintenance

Peer-to-Peer:

• Advantage of P2P:
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    • Easy and inexpensive (often free) to set up and use.
• Disadvantage of P2P:
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    • Lack of security controls or other common management functions.

500

What is the most widely used topology and what is the topology also known as hierarchical?

Star and Tree 

Organizational Networks and Network Securities

100

What is an Intranet?

A private network within an organization that resembles the Internet.

200

What is a firewall?

A security system designed to protect an organization’s network against external threats. Consists of hardware and software that control access to a company’s intranet or other internal networks.

300

What is an extranet and its main purpose?

What? A private network that connects more than one organization.

Main purpose? Increase efficiency and reduce costs. 

400

What is the long form of VPN and what does it do?

Virtual private networks. 

• Create a secure private connection between a remote users and an organization’s internal network.

500

What is the long form of IDS and what does it do?

Intrusion detection systems 

• Works with firewalls to protect an organization’s network.
• Uses sophisticated statistical techniques to analyze all incoming and outgoing network traffic.
• Uses advanced pattern matching and heuristics to recognize signs of a network attack and disable access before an intruder can do damage.

Networks and Network types

100

Describe a Local Area Network (LAN)

Networks with nodes that are in close physical proximity, typically spanning less than a mile and are owned and operated by individual organizations.

200

What is a switch?

• Switch—central node that coordinates the flow of data by sending messages directly between sender and receiver nodes.  

300

What is a network gateway?

It is a device that allows one LAN to be linked to other LANs or larger networks.

400

What is the range of PAN, MAN, and WAN?

PAN - around 30 feet

MAN - span distances up to 100 miles. 

WAN - span distances greater than 100 miles. 

500

What is the difference between Network interface cards (NIC) and Network operating systems (NOS)?

Network interface cards (NIC)— expansion cards located within the system unit that connect the computer to a network.

Network operating systems (NOS)—control and coordinate the activities of all computers and other devices on a network.

Connection devices and Data Transmission

100

What is Protocols and Bandwidth?

Protocols are the rules for exchanging data between computers. 

Bandwidth is a measurement of the width or capacity of the communication channel.

200

What is the role of a modem?

• Modems convert the computer’s digital signal to an analog transmission to send over the phone line (modulation) and then re-convert it to digital when receiving information from the phone lines (demodulation).

300

What is the main difference between Broadband and baseband?

Broadband, several users can simultaneously use a single broadband connection for high-speed data transfer. 

Baseband, can only carry a single signal at one time. 

400

Explain either Identification or Packetization

• Identification: Every computer on the Internet has a unique numeric address called an IP address (Internet Protocol address). Uses a domain name server (DNS) that automatically converts text-based addresses to numeric IP addresses.
• Packetization: Before a message is sent, it is reformatted or broken down into small parts called packets. Each packet is then sent separately over the Internet, possibly traveling different routes to one common destination.  At the receiving end, the packets are reassembled into the correct order.

500

Describe any one of the cellular service generations

1g (first generation mobile telecommunications) started in the 1980s using analog radio signals to provide analog voice transmission service.

2g (second generation mobile telecommunications) stared in the 1990s using digital radio signals.  This generation focused on voice transmission and was too slow for effective Internet connectivity. 

3g (third generation mobile telecommunications) started in the 2000s providing services capable of effective connectivity to the Internet and marked the beginning of smartphones.

While 4g (fourth generation mobile telecommunications) has been widely marketed by several cellular services, not everyone acknowledges that this generation has begun.  Most experts, however, do acknowledge that 4g has entered into its infancy with providers using WiMax and LTE connections to provide faster transmission speeds. While current speeds are only marginally faster than 3g, 4g technologies promise to provide speeds up to 10 times faster than 3g in the near future. 

Communications and communication channels

100

What are the four basic elements of a communication system?

Sending and receiving devices 

Connection devices 

Communication channel 

Data transmission specifications

200

Describe any one physical connection of the communication channels

• Twisted pair – pairs of  copper wires twisted together
• Coaxial cable - a high-frequency transmission cable consisting of a single, solid copper core. See
• Fiber-optic cable - transmits data as pulses of light through tiny tubes of glass.
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300

What is the Wireless Revolution?

The widespread use of mobile or wireless telephones

 

400

Describe any one of the wireless connections:

Bluetooth

Wi-Fi

Microwave

• Bluetooth is a short-range radio communication standard that transmits data over short distances of up to approximately 33 feet.  Bluetooth is widely used for wireless headsets, printer connections, and handheld devices.
• Wi-Fi (wireless fidelity) uses high frequency radio signals to transmit data.   A number of standards for Wi-Fi exist, and each can send and receive data at a different speed. 
• Microwave - communication through high-frequency radio waves.  It is sometimes referred to as line-of-sight communication because microwaves can only travel in a straight line.

500

LTE (long term evolution) although similar to WiMax performance-wise, what does it promise in the near future?

 LTE promises to provide greater speed and quality transmissions in the near future.