First Quarter Marking Period Assessment

1. Computer Networks First Quarter Marking Period Assessment

2. Circuit-Switched Network • Which is the best definition of a circuit switched network? • An electric circuit where the connections get switched based on who is calling whom at a given moment

3. Digital Packet • What is a digital packet? • Computers separate the information they want to send across a network into smaller pieces called packets that travel along different routes to their destination

4. EMI • What is EMI? • Electromagnetic interference is produced by electromagnetic waves from electromagnetic devices that can degrade the signal your computer or computer monitor received • Examples of electromagnetic devices include: cell phones, cordless phones, pagers, electric space heaters, other motorized devices

5. RFI • What is RFI? • Radio frequency interference is an unwanted radio signal that prevents clear reception and can degrade the signal your computer or computer monitor receives • It is typically caused by garage door openers, remote control devices, AM and FM radios and antennas

6. Network components • 1. They are used in networks that need to send messages across longer distances than the wires themselves can carry the message (booster) • 2. They have all of the abilities of a router, plus they can translate between network protocols (gateway) • 3. They do not read MAC addresses, so they send data packets to all the computers on the network (hub)

7. Network Components • 4. Directs incoming messages to the right computer and directs outgoing messages to the fastest route to their destination (switch). • 5. A circuit board that allows you to plug in an Ethernet cable and connect your computer to a network or the internet (network interface card) • 6. Smarter versions of hubs that can read the MAC addresses attached to data packets (router)

8. Digital Signals • Which of the following statements are true about digital signals? • Computer systems use binary code to communicate • Ones and zeros are strung together to form instructions to the computer • Computer networks use electric pulses across wire to communicate • The ups and down in the waveform show changes in frequency • All of the above (correct answer)

9. Analog Signals • Which of the following statements is true about analog signals? • In the world around us, very few sounds are actually analog sounds (not true) • Early cell phone systems used digital radio waves to transmit voice signals (not true) • Analog signal is a wave pattern that is not continuously variable (not true) • Digital cell phones compress your voice into analog information (not true) • Modems are used to connect computers to the Internet via analog phone lines (True)

10. Network Topologies Star topology connects computers using a hub or a switch. Very common; easy to design and implement Advantages: simplicity of adding additional nodes. Disadvantage: hub represents a single point of failure. Ring topology is no longer common. The network sends a token around the ring and only one computer can hold the token at once. Only the computer holding the token can send information. Disadvantages: switches are smarter at routing data to specific addresses Full mesh topology links every device to every other one. Advantages: has the highest fault tolerance of all the networks. Disadvantages: costly, more complex. Rarely used today. WAN implementations sometime use a partial mesh where all computers can connect to all others by going through no more than a few nodes. With Bus topology every computer taps into a central cable. Advantages: easy to connect and requires less cable than star. Used mostly on large scale networks to connect smaller networks. Disadvantages: if the central cable breaks it divides the network into two separate sections.

11. Network Topologies • You will be asked to design a small LAN for a T-shirt company. You will have to recommend which network topology will work best and explain why. • You will also have to decide whether client/server to peer-to-peer network would be best and describe the features and benefits of each.

12. Client Server Network • In client/server networks, one computer is set up to function only as a server. • The server controls the access that other computers have to shared resources such as files and folders that are stored on the server. Employees folders can be password protected. • The network administrator can back up documents that are stored on a server more easily. If one of the computers crashes, the information is still available on the server. • Some servers perform multiple tasks such as storing and retrieving documents, serving up Web pages, printing, or allowing employees to access email.

13. Peer-to-Peer Networks • On peer-to-peer networks all computers have equal ability to communicate and control documents. • All computers can share files with others, request files from other computers, and access office machines such as printers. • Security is typically controlled by the end user (the employee who used the computer) who configures who can see what on his/her computer.

14. OSI Seven Layer Model • List the seven layers of the OSI Seven Layer Model starting with layer 1: • Physical • Data Link • Network • Transport • Session • Presentation • Application

15. Protocols and Standards • Write a short essay that describes the process that takes place at the layer of the OSI Seven Layer model for which you made a collage. State the imagery you used, the process, and the layer devices and protocols used at that layer.