Chapter 8: Networking and Internet Basics 1 Satellites
Chapter 8: Networking and Internet Basics 1 Satellites can be used for broadband communications 2 Chapter 8: Networking and Internet Basics Learning Objectives: Identify communications networks in daily life Distinguish between types of networks Identify common types of network hardware
Understand the Internet and choose a connection method Troubleshoot common network and Internet connectivity problems 3 Public Telephone and Data Networks The telephone network: is the first worldwide network ever created, predating computers by many decades. is an example of a circuit-switched network. A circuit-switched network works by creating:
Point-to-point connection between the two locations Communication channel stays open for the duration of the communication. 4 Public-Switched Telephone Network (PSTN) Networks can be:
public , or private Public: Public-switched telephone network (PSTN): The worldwide network of circuitswitched telephone lines (i.e. telephone networks) (the public telephone system) 5
Packet-Switched Networks Computer networks are packet-switched networks (instead of circuit-switched as for the telephone) Packet-switched networks: Communication channel does not remain open the whole time Data is broken up at the sending end into small packets and routed individually to the receiver Each packet may take a different route to the
destination Example: Internet is a global packet-switched network 6 Packet-Switched Networks 7 The Internet Packet-switched network with a worldwide addressing system
Not owned or maintained by any one company Multiple standards organizations manage the protocols (rules) The Internet uses various protocols that all participating computers have standardized on: services like the web, email, and instant messaging work the same everywhere. 8 The Internet Most companies and individuals dont connect directly to the Internet;
They connect to an Internet service provider (ISP), which in turn connects to the Internet. Internet is based on TCP/IP* protocol stack** (set of protocols) Common set of standards Use in most private networks too IP addressing identifies each device by a numeric value
(*) Transmission Control Protocol / Internet Protocol A protocol suite (set of rules) that defines how data will move on the Internet and on most other modern networks (**) A related group of protocols for example, TCP/IP 9 Private Digital Networks In the case where companies maintain their own high-speed connections between locations, by: Leasing lines from the phone company, or
Virtual private network (VPN) through the Internet Use the above private networks because Internet is not the most reliable method: Can be affected by Internet traffic and connection problems Internet not very secure 10
Leasing a Line Leasing a line running their own cables, or using the existing pathways of the Internet. Using the Internet is the most cost-effective method, but not the most reliable method Because the connection can be affected by: internet traffic problems, and connections that other companies control and maintain. 11
Leasing a Line 12 VPN technology VPN technology: creates a secure, tamper-resistant data tunnel between two points on the Internet, so that sensitive information can be exchanged securely allows an employee who is working outside of the companys main building to connect to any of the internal network resources, just as if he were in the building A VPN creates a secure connection betw. Two points using the13
Internets infrastructure to physically carry the data Satellite Data Networks A satellite is a transmitter/receiver unit that orbits the Earth, more than 22,000 miles up. Satellites are in geosynchronous orbit (i.e. their orbit is synchronized with the Earths orbit) they do not appear to change in position compared to any location on Earth.
A satellite contains transponders (they are two-way radios that communicate with stations on the ground) 14 Satellite Data Networks Satellites are also used to quickly send information between two points on Earth that are physically separated by a great distance. Satellites are also used for services like :
Satellite radio and TV distribution DirecTV, Dish Network Sirius, XM radio Satellite Internet services to consumers Some Internet services also use satellites to provide Internet access to areas where other high-speed connections technologies are not available. 15
Satellite Data Networks Satellites can be used for broadband communications 16 Cell Phone Networks Cellular telephone companies have their own data networks: using a combination of satellites, cables, and onground towers. Calls connect to the tower closes to them The tower then taps into the larger network
Cell networks (3G/4G) can access the Internet You can tether (connect) a smartphone* to a computer and use the phone as a modem * A cellular phone that includes computer applications and Internet access capability 17 Ways of Classifying Networks There are several ways to classify computer networks: Geographical Range Peer-to-Peer and Client/Server Intranets and Extranets Ethernet
Wireless Technologies 18 Geographical Range One way to classify networks is according to the geographical range that they cover, from a few feet within a single persons office to a huge area that covers multiple countries or even multiple continents. Graphical explanation of some of these ranges. Personal area network: single user Local area network: in the same building or campus Metropolitan area network: in the same city
Wide area network: on the same planet 19 Geographical Range 20 The geographical range of linked devices determines the type of network that connects them Geographical Range PAN A personal area network (PAN) consists of devices that directly connect to a single computer. LAN
A local area network (LAN) is a network in which all the devices are located within the same physical location, such as a single building or a group of adjacent buildings. 21 Geographical Range MAN A metropolitan area network (MAN) is a network that spans an entire town or cityor, as the name implies, a metropolitan area that might span a major city and its suburbs. WAN A wide area network (WAN) is a geographically dispersed network, usually consisting of at
least two LANs connected together by an external link 22 Peer-to-Peer and Client/Server Networks Peer-to-Peer Networks No servers Good for small groups of computers (<10) Every computer shares administrative responsibilities on peer-to-peer networks, which have no servers 23
Peer-to-Peer and Client/Server Networks Client/Server Networks * One or more dedicated servers Central management of security and identities Good for large groups of computers (>10) * Client: A computer used by an Individual to run applications Client /Server Networks have one or more servers through which multiple computers can perform various tasks
24 Intranets and Extranets Intranet A secure network that only staff within the company can access, and only on-site Extranet A secure network that is that is set up by a business for its customers, staff and business partners to access from outside the office network It may be used to share marketing assets and other sensitive items. 25
Ethernet The current dominant standard for local area networking devices Can be wired or wireless Wireless version is also called Wi-Fi or 802.11 Devices have a maximum speed, such as 1 Gbps Twisted-pair copper cable is the most common medium 1000BaseT means 1000 Mbps (1 Gbps) and twisted pair cable (T for twisted) 26 Wireless Networking
A network can connect devices using either wired or wireless connections. A wired connection runs a cable between the points, whereas A wireless connection connects the two points via radio frequency (RF) or infrared. Two main uses:
Endpoints of connectivity: laptops, smartphones Relay between network segments: when cable connection is not practical 27 Wireless Networking Wi-Fi (wireless fidelity) The common name for the wireless networking technology used for almost all home and business networks today often referred to by its standard number: IEEE 802.11.
Wi-Fi Standards 28 Wireless Networking Bluetooth A wireless technology used to connect individual devices to one another in close proximity. Used most commonly to connect a computer to an input or output device (these should be paired). Used to connect personal devices such as headsets Used to create personal area networks Range limit of 20 feet Examples of use:
a Bluetooth headphone with smartphone a Bluetooth enabled printer with Notebook 29 Wireless Networking Infrared (IrDA) Uses light waves to beam information between devices IrDA is the standard (Infrared Data Association) Older technology, mainly replaced by Bluetooth Still used in TV remote controls
30 Wireless Networking Microwave High-frequency radio waves A microwave communication system: is a secure point-to-point wireless networking technology Requires a line of sight between the two points The points can be miles apart (up to about 25 miles) The transmitters are often placed high up on towers or building Was prior to the development of satellite
networking systems 31 Network Hardware Network connectivity requires both hardware and software. The software portion is handled by the operating system; all modern operating systems include network support. Not all computers include
networking hardware Some network hardware is independent of any one computer 32 Network Hardware Network Adapter* Provides networking interface hardware needed for a computer to connect to a network Can be built into motherboard or separate Has a unique Media Access Control (MAC)
address * When a network adapter is not built into the motherboard, but installed as an expansion card , it is called NIC (Network Interface Adapter) 33 Network Hardware Switches and Hubs A switch is a box that provides a central gathering point for all the computers in an Ethernet LAN. Each computers network adapter connects to the switch, either via a cable or wirelessly. Both are gathering points for computers in an Ethernet LAN
A switch manages data traffic between devices A hub is dumb, and sends all data to all ports A wireless switch is a wireless access point (WAP) 34 Network Hardware Hub 35 Network Hardware Router Performs the same functions as a switch Can also direct traffic into and out of your LAN
Is typically used to direct traffic to/from an Internet connection The output port is the default gateway Can include wireless connectivity or not 36 Network Hardware Router 37 Network Hardware Other Devices
Gateway: Connects dissimilar networks Bridge: Connects similar networks Repeater: Receives and retransmits a network signal Repeater Bridge 38 Network Cables Twisted-Pair Cable Transfers data with pairs of copper wires Wires are twisted to reduce interference (EMI) within the cable
electromagnetic Standard cables are unshielded twisted pair (UTP) 39 Network Cables Shielded twisted pair (STP) is more expensive and protects against EMI from outside the cable UTP vs. STP 40
Network Cables Coaxial Cable Used for cable and satellite TV Connects cable TV service or satellite dish to broadband modem Carries data through a single copper core Carries data faster than UTP but is more expensive A coaxial cable has a solid copper core in the center, surrounded by insulation 41 Network Cables
Fiber Optic Cable Carries data with light pulses Each fiber is about the width of a human hair Each cable contains hundreds of fibers Often used as the backbone of a network Expensive and difficult to install Fast, secure, and not subject to EMI A fiber optic cable contains multiple thin strands of glass fiber 42 Connecting to Internet Internet Structure
Mesh of interconnected routers Data may take any available path to its destination A mesh network does not rely on any one point being active; Traffic can easily route around any blockages 43 Connecting to Internet Internet Speed Internet does not have a fixed speed Throughput depends on the capabilities of the segment the data is passing through
Backbone (main roads) of the internet are high-speed lines Individual service speed has a theoretical maximum and an actual speed 44 Connecting to Internet Factors that Affect Internet Speed Internet traffic Local traffic Server issues Throttling 45
Types of Internet Connections Dial-up Oldest, slowest, last resort Tops out at around 44.8 Kbps Ties up a phone line Uses a dial-up modem Dial-up
46 Types of Internet Connections Cable Internet Comes through cable TV cable Uses a cable modem Fast speed Can be optionally shared throughout the home or business
Cable Internet 47 Types of Internet Connections Digital Subscriber Line (DSL) Comes through telephone land line cable Moderately fast speed Newer kind, Very High Bit Rate DSL (VDSL), rivals cable Internet in speed Satellite Slower than cable or DSL Available in places where other broadband is unavailable
Requires professional installation of satellite transmitter Bandwidth may be throttled 48 Types of Internet Connections Internet over Cell Phone Networks Available anywhere 3G or 4G cell phone service is available Phone can be connected to a computer (tethered) to provide the computer an Internet connection Can be expensive on a limited data plan; beware of overages
49 Key Terms 1000BaseT 3G 4G backbone bandwidth Bluetooth Bridge broadband cable modem category 3 cable category 5e cable circuit-switched
(STP) smartphone switch tether Transmission Control Protocol/ Internet Protocol (TCP/IP) twisted-pair cable unshielded twisted pair (UTP) virtual private networking (VPN) wide area network
(WAN) Wi-Fi wireless access point (WAP) 51 Summary 1 . List three types of wireless connection. 2 . How do a switch and a router differ? 3 . Explain the difference between STP and UTP cable. 4 . What kind of cable would you need for a 1000BaseT network? 5 . What is TCP/IP?
6 . List four ways to connect to the Internet. 7 . List two things to try if your computer is connected to a network but cant access the Internet. 8 . Why is satellite Internet not more popular? 52
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