Computer Networking Part 2

Computing Essentials

Lesson 4:

Computer Networking: Part 2

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​!Open up your Google Site and be ready to take notes!

But first...​

Let's review what we covered yesterday!​

Computer Network

• ​2 or more computers (or network devices) connected form a network

• ​Enables us to share files, printers, email, and many other resources

• ​Examples of devices include: computers, laptops, phones, printers, scanners, routers, servers, and so much more.

​Local Area Network (LAN)

• ​A group of connected computers within a small geographic area

• ​Range in size and scale based on use

  • ​home network

  • ​school network

  • ​small office network

• ​Wireless LANs (WLANs) extend a LAN to provide wireless connection

​Metropolitan Area Network (MAN)

• ​a network that operates within a large city or multiple small cities (AKA Metro area)

• ​much larger than a LAN because it covers a larger geographic area

• ​typically operated by local governments or private companies

​Wide Area Network (WAN)

• ​The largest network type

• ​Connects 2 or more LANs together

• ​Owned and maintained by the owner of the LANs it connects

• ​The largest WAN in the world is The Internet

Intranet

• ​behind a company firewall (restricted access)

• ​content and files are only accessible by company employees granted permission

• ​Company: calendars, photos, projects, news, groups, etc

​Extranet

• ​very similar to intranet, but can be accessed from outside the physical location of the organization.

• ​usually requires login/password

​Virtual Private Network (VPN)

• ​Secure network connection that allows access to a private network across a public network (such as The Internet)

• ​Secure "tunnel"

• ​Users get a special username & password to access company resources remotely

• ​Enables employees to work from home, grant contractor access, etc

​Network Topologies

​The way a network uses a PHYSICAL layout scheme tells us what type of NETWORK TOPOLOGY it is using.

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​Each topology has a different and unique purpose for the sharing information across the network.

• ​Bus

• ​Star

• ​Ring (aka Token Ring)

• ​Mesh

​BUS Topology

• ​Connects devices through ONE (1) physical line

• ​Information can flow in only 1 direction

• ​Only 1 computer can send data at a time

• ​Requires a "terminator" at the end of the cable

• ​If the cable fails, the entire network goes down

​STAR Topology

• ​Each computer/device connects to one (1) network device

• ​Network device receives info and transmits it accordingly

• ​High speeds because computers can communicate simultaneously

• ​If one (1) cable fails, most of the network keeps running

• ​Most common topology today

​RING (aka Token Ring) Topology

• ​Connects all computers through one (1) single line

• ​Only one (1) computer can send data at a time

• ​Computer must possess a "token" to send data

• ​"Token" is passed clockwise

• ​If main cable fails, entire network goes down

​MESH Topology

• ​Each computer has a DEDICATED connection to EVERY OTHER COMPUTER.

• ​If one cable fails, the entire network is still running

• ​Most secure and reliable

• ​Most expensive topology due to the amount of cable required

And now...​

On to new material!​

​Lesson Objectives

• ​Identify common network models

• ​Describe the functions of various network hardware

• ​Compare and contrast various methods of network connectivity

  ​Describe the OSI reference model and each layer

• ​Explain how two network nodes communicate through the OSI model

Client/Server Network Model

• Most commonly used model

• ​Client = the user's computer

• ​Server = the user requests to use the server

• Server ​Examples:​ file, print, ​e-mail, domain controller

• ​Advantage: companies can control security and file backups

• ​Disadvantage: Expensive and if the server fails, it could stop all work

Mainframe/Terminal Network Model

• Has a main host that other computers interact with

• ​However, mainframe computers run ALL programs directly on the mainframe instead of on individual computers

• ​The terminal computers are simply "access points" to log into the mainframe

• ​Advantage: security and software installed on mainframe only

• ​Disadvantage: Very expensive and network goes down if mainframe goes down

Peer-to-Peer Network Model

• Allows computers to connect to each other

• ​Each computer is "both the server and client"

• ​Advantage: cost effective and flexible

• ​Disadvantage: security risks, possible legal issues, and extremely difficult to troubleshoot

Multiple Select

Which network models provide pretty good overall security?

• Client/Server

• Mainframe/Terminal

• Peer-to-Peer

Multiple Choice

Which network model do you run ALL applications on a central computer?

• client/server

• mainframe/terminal

• Peer-to-Peer

Multiple Choice

Which network model can cause legal issues in operating/using it?

• client/server

• mainframe/terminal

• Peer-to-Peer

Multiple Choice

Which network model is the most commonly used by most companies?

• client/server

• mainframe/terminal

• Peer-to-Peer

​Connecting to a Network

​Computers - desktop, notebook, tablet, mobile devices

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​Operating system - Windows, Linux, Mac OS, Mobile OS's, Chrome OS, etc

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​Network media - the material used (wired or wireless) that connects devices

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​Network hardware - physical hardware connecting computers across a network

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​Network protocol - set of rules defining HOW the computers on the network communicate

Network Media

BROADBAND - high-speed, data cables connect computer together. (Media: coaxial, fiber-optic, and twisted-pair cable <cat5/cat6 etc>)

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​Wi-Fi (802.11) - Wireless standard for using a WLAN. Based on IEEE 802.11 which has many versions (802.11a, 802.11b, 802.11g, 802.11n, and 802.11ac)

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​BLUETOOTH - connects device directly to another by pairing. Best for short range uses (e.g. headphones, speakers, mouse, etc)

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​CELLULAR - Use cell towers to connect wirelessly (3G, 4G, 5G, etc)

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​SATELLITE - Wireless through satellites, limited speed, line-of-sight req'd

​Broadband Media Cables

​Coaxial cable Fiber-Optic cable Twisting Pair (CAT-6 etc)

Multiple Choice

Another name for the wires/wireless connection options available to connect computers

• operating system

• network media

• network hardware

• network protocol

Multiple Choice

Another name for the routers, hubs, switches, servers, etc

• operating system

• network media

• network hardware

• network protocol

Multiple Choice

The rules defining how computers communicate together on a network

• operating system

• network media

• network hardware

• network protocol

Multiple Select

Which are NOT wireless network standards?

• 802.11b

• 802.11ac

• 801.11n

• 802.13g

​The OSI Reference Model

Created to standardize how computers communicate with one another

​"All People Seem To Need Data Processing"

Multiple Choice

Which layer of the OSI model is the starting point (transmitting) and end point (receiving) of data as it passes through networks?

• physical

• application

• transport

• data link

​Terms we added to our Google Site today

1. ​client/server network model

2. ​mainframe/terminal network model

3. ​peer-to-peer network

4. ​network media

5. ​network hardware

6. ​network protocol

7. ​broadband

8. ​Wi-Fi (802-11)

9. ​bluetooth

10. ​cellular

11. ​satellite

12. ​OSI Model (all 7 layers)