Chapter VI Networking fundamentals DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 1

Transcription

1 Chapter VI Networking fundamentals COMPUTER NETWORKING AND THE INTERNET DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 1

2 Objectives Understand networking Understand networking topologies Understand networking protocol Understand the Internet Understand Internet protocol Recognize and understand important special networks. Understand how to apply this information to business. DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 2

3 What is networking? Networking as defined in Merriam Webster dictionary is the exchange of information or services among individuals, groups, or institutions; specifically : the cultivation of productive relationships for employment or business. Modern computer networking is in fact business networking as it is hard to imagine business information networks that don t evolve around computers and computer information system. Networking wouldn t be this easily possible and profitable without the abundance of advanced telecommunication technology DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 3

4 Computer network Computer network consists of at least 3 computers linked together by means of telecommunication media. Computer networks are usually tailored to match the structure of a given establishment, business or any organization. Each computer in the network is known as a node or workstation. If the network has a server all other nodes are considered as clients DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 4

5 Network physical topology Physical structure of the network Star topology: Typical client-server network Nodes or clients centralized around a server. Most used topology in networking technology. client1 client2 server client4 client3 DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 5

6 Bus topology Consists of backbone cable (bus) all along the network area. No server in a bus network. Nodes share files and other information. Easy to connect and monitor network. Bus (Network backbone) node 1 node 2 node 3 node 4 DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 6

7 Ring topology Consists of several computers connected as a ring Imagine a bus network with both ends linked. Message flow and priorities are clockwise n5 n1 n2 n4 n3 DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 7

8 Mesh network topology Each node is connected to all other nodes Expensive structure if we need to lay a huge quantity of cables or implement other media for this purpose. Pier-to-peer network: Special mesh structure that uses the Internet backbone as a communication medium with each node in the network. Very flexible structure as it may connect unlimited number of nodes that may include every computer that has Internet connection. n5 n4 n1 n3 n2 DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 8

9 Tree networking topology This network fits a department that comprises several divisions where each division has a star network and all stars are connected via a bus. Priorities and message flow control are more complicated in this network structure. Backbone (BUS) DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 9

10 Network logical topology Network protocol: Can be defined as the network logical topology and consists of a set of rules designed to control all network functions by assuming the following responsibilities: Establishing network priorities and enforcing them. Maintaining strict communication discipline in the network. Controlling network access and network security. Establishing communications with network nodes from internal nodes and external messages applying the handshaking technology. What is handshaking technology? DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 10

11 Handshaking technology Consists of the following steps achieved by the network protocol: Protocol detects a message originated by node A or coming from outside source addressed to node B Protocol intercepts the message and inspects its validity and security status and make sure it doesn t collide with other network messages. Protocol warns node B about the message by checking if it is available and willing to receive it. To complete the handshaking process, protocol connects the sender with the receiver allowing the message to flow from origin to destination. If node B is busy with other messaging business the handshaking process will be postponed as long as necessary. DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 11

12 Ethernet protocol Was commercially released in 1980 and it is until today the most popular protocol among LAN users Ethernet technology is known as CSMA/CD which stands for (Carrier Sense Multiple Access/Collision Detection. This technology is based on the principle of polite conversation between a group of civilized people with the following scenario: Many people start talking at the same time. They stop talking because each one of them will leave the turn to others. When an absolute silence is achieved, some guys will restart talking and again if more than one is talking they will stop. The process will continue until only one is talking and all others listening Ethernet protocol assumes the enforcement of the courtesy role by stopping all messages if more than one station is trying to send. Ethernet sends the message to all nodes but none can receive it except the addressees. DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 12

13 Token ring protocol This protocol is designed for the ring network A signal called token that may be a code is sent to the station that has the sending priority. When that station finishes it passes the token to the station that has the next priority and so forth In a ring network priorities are clockwise in the order and the message flows clockwise exactly. DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 13

14 Wireless networking WLAN network connects nodes via radio-waves instead of cables. It is known as Wi-Fi network and the latest wireless technology is the Wi-Max network. Wi-Fi network stands for (Wireless-Fidelity) and is known by its IEEE code where we must distinguish from a, b, g, and n DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 14

15 Wireless networking was released in 1997 uses a 2.4 GHz and bandwidth 20 MHz can be used over a distance of 20 meter indoor and 100 meter outdoor a released on the eve of the 3 rd millennium SEPT-OCT 1999 uses a 3.7 GHz frequency and 20 MHz bandwidth that improved the range to 35 meters indoor and 120 meters outdoor b uses 2.4 GHz and same bandwidth of 20 MHz with the improvement of the outdoor working distance to 140 meters g similar to the b and data rate between 6 and 54 (Mbit/s) and was released in June n released in OCT 2009 used a 2.4/5 GHz frequency and bit stream between 7.2 Mbit/s and 72.2 Mbit/s the working range was improved to 70 meters indoor and 250 meters outdoor. Other scheduled releases for 2013 (802.11ad) and 2014 (802.11ac) that will introduce new improvements to the WLAN technology. DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 15

16 WI-MAX Wireless broadband Internet access designed to replace the DSL as more convenient mobile and fixed Internet access. Wi-MAX influence on Internet access may be compared tp cellphone impact on the telephone networking and telephone industry. The IEEE and e standard enable to use 2.3 GHz, 3.3 GHz, 2.5 GHz and 3.5 GHz. Wi-MAX range may reach 50 Kilometers about 31 miles (enough to cover a big city or a county). DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 16

17 WI-MAX (continued) Designed to provide Mbit/s that was updated in 2011 to 1 Gbit/s for fixed stations. However Wi-MAX has the limitation of not being able to deliver the maximum speed at the maximum range ( speed in bit/s is inversely proportional to the distance from the base station). Wi-MAX started the 4 th generation (4G) of smart phones and mobile Internet access that evolved as follow: LTE (Long Term Evolution) is defined as a 4G standard was effectively first launched in 2009 in Scandinavia (Oslo and Stockholm). Wi-MAX 1, 1.5 and 2 were all designed as wireless MAN (Metropolitan area Network). Wi-MAX release 2 core technology (802.16m) provides data speed 4 times faster than the first release and e m release 2 is backward compatible with Wi-MAX release 1 so the migration from Wi-MAX 1 to Wi-MAX 2 needs only to update the software or upgrade the channel cards. By the start of 2012 Wi-MAX networks around the world were estimated to have more than one billion subscribers. DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 17

18 Blue-tooth wireless technology Bluetooth networking technology was developed in 1994 in the labs of ERICSSON (the Scandinavian communication giant company) by 2 employees Jaap Haartsen and Sven Mattisson It was called by this name after the Scandinavian king Harald ( ) who was very productive in building bridges and making all Scandinavian tribes communicate with each other. This king was nicknamed BLUETOOTH because his front teeth were blue colored affected by his love of eating berries. Bluetooth is a full wireless networking technology using low power transmitters that are designed to link computing devices in PAN (Personal Area Network) over short distances (10 meters = 33 feet or less). Newer Bluetooth technology using more powerful transmitters can be used for up to 100 meters or 330 feet. The frequency band used is MHz divided into 79 channels one MHz apart assigned by the ISM (Industrial Scientific Medical) agency. DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 18

19 Bluetooth (continued) The basic network in a Bluetooth system is the Pico-net up to 8 nodes because the address is 3 digits (2^3 = 8). Each device in Pico-net is a peer device (it can act a master or a slave so at a given time we have one master and 7 slaves. Two or more Pico-nets form a scatter-net A scatter happens when one slave of any Pico-net elects to behave as master or slave in another one. This interconnectivity enables Bluetooth devices to reach beyond the short range of Bluetooth network. DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 19

20 Bluetooth protocol because of the diversity of Bluetooth devices the technology has a stack of several protocols to handle diverse services and provide for implementation flexibility. These protocols are: LMP (Link Management protocol) establishes and manages links and ability to query. BNEP (Bluetooth Network Encapsulation Protocol) used by Bluetooth PNA to manage packet switching and transmission in the network. HCI (Host Controller Interface) establishes and controls communication between operating system of computer devices and Bluetooth IC (Integrated Circuit). SDP (Service Discovery Protocol) enables any Bluetooth device to discover services offered by other devices and their characteristics and parameters. TCS and TCS-BIN (Telephony Control Protocol allows voice and data calls between devices of Bluetooth network. WAP (Wireless Application Protocol) provides necessary access to telephone and computer networks for mobile users who are connecting thru Bluetooth network. DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 20

21 Samples of Bluetooth apps: PROFINET: Bridge that connects two Ethernet networks. Wii of Nintendo and PS3 of Sony game consoles use Bluetooth to accommodate their game controllers. Personal security application: Bluetooth tag (marker) attached to protected objects and has constant communication with a phone. If the communication is interrupted a warning signal is activated. RTLS (Real Time Location System) app that enables user to track and locate objects by attaching or embedding Bluetooth markers or tags and using readers to intercept and process signals sent by the tags. Bluetooth OBEX (Object Exchange) is an application that allows exchange of information and transfer of files within all devices of Bluetooth network. DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 21

22 Internet Internetworking: The basic idea behind Internet invention is connecting networks with each other creating a network of networks (MAN or WAN). This process is known as internetworking and several technological steps were already set up that guided to the Internet. Networks may have different topologies and different protocols and to connect them we need to set up a conversion or translation service between them. Connecting networks: Two similar networks (same protocol) are connected by means of a bridge whose job is to connect 2 or more segments and control packet flow between them. Two dissimilar networks (have different protocols) are connected by means of gateway device which provide assistance to make sure the message flows uniformly in both networks Network switch links segments of the network to bridges or gateways. Basic switches don t process data. A switch that does process data is called multilevel switch because it will be working at a level 3 processing. DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 22

23 Packet switching Internetworking technology will be impossible with circuit switching that allows fewer messages to use the network pathways simultaneously. Packet switching, on the other hand, optimizes the use of network pathways by dividing each message into parcels of data called packets whose trips take short time. Packets are sent from A to B using most available pathways between them instead of only one like in circuit switching. Consider the following scenario of 9 packets going from A to B. Packet1 takes itinerary I1 Packet2 takes Itinerary I2 and so on Packet9 takes Itinerary I9 Upon arrival to B, a guide will gather them regroup them and deliver them altogether one message as they initially were. An internetwork is basically a small Internet the biggest internetwork of all networks and internetworks is the Internet that controls our daily life (as individual, community, society, business, government and so on ) DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 23

24 Internet protocol Internet protocol TCP/IP (Transmission Control Protocol/Internet Protocol) was the right solution where each part fulfills a specific job making the process very fast to handle the huge number of exchanged packets: TCP (Transmission Control Protocol) is the part that takes care of the packet at the origin and destination making sure they are well prepared at the origin and assemble them prior to the correct delivery at the destination. TCP cuts the message into packets below 1500 bytes each because Ethernet protocol in LANs cannot take more than 1500 bytes. IP (Internet Protocol) is the part that takes care of addressing the packets and directs them thru their proper itineraries. DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 24

25 Internet backbone Internet backbone can be compared to human backbone or spine because it connects every internet host user to other users like human backbone connect to every organ and cell of the human body. This backbone comprises all fast and broad band networks and connections owned by major telecommunication companies (AT&T, Spirit, French telecom, Finn telecom, etc ) all around the world including: Under ocean cables installed by submarines and known as submarine cables that link most continents. Satellites owned and operated by large telecommunications companies because the private sector took over in Ground high speed telecommunication and networking infrastructure including wired and wireless infrastructure. DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 25

26 Internet status Nobody own the Internet, however big telecommunication companies own parts of the Internet backbone and make profit by charging use fees so Internet providers can be divided into 3 tiers: Tier 1: comprises huge ISP (Internet Service Provider) companies that don t need to pay anything to access all nodes of the Internet. Qwest, AT&T, Verizon, sprint, French telecom, Finn telecom etc Tier 2: comprises ISP companies that need to pay for some access from Tier 1 companies. Tier 3: Comprises ISP companies that lease Internet access from Tier 1 or Tier 2 companies provide services to subscribers and don t own connections by themselves. Tier 1, Tier 2 and Tier 3 companies are all Internet service providers (ISP)s and that s why the quality of Internet service is normally better with Tier 1 companies then Tier 2 then Tier 3. DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 26

27 Internet access Five most important characteristics of Internet access are: Reliability: Connection is available when needed without unexpected interruption due to coverage and weather Speed: Download speed and upload speed in Mbps. Cost should be reasonable and justified. Customer satisfaction oriented help and assistance service Free array of popular general information News Weather Gaming Travel and entertainment. ISP (Internet Service Provider) provides a modem (modulator demodulator) that is able to accommodate all services provided. DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 27

28 Internet access methods Dial-up connection: The first used method of access Host must dial a number and wait until getting access. Very slow access impossible to deal with multimedia because it can only handle up to 56 Kbps Uses telephone line so you cannot use the telephone and access the Internet simultaneously (one service at a time) Service is ON only after you dial and be lucky to get connected Still used in some rural areas where there is no fast Internet yet. The least expensive service of all. DSL (Digital Subscriber Line) Always On Internet service Provided by telephone companies and uses telephone lines. Because of switching technology provided by the ISP, you can use both the telephone and the Internet simultaneously. Fast Internet that may go up to 6 Mbps. Price is reasonable but much higher than dial-up connection service DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 28

29 Cable TV: provides the connection as part of a package that includes TV channels and possible more services like Internet telephone Always ON connection A splitter modem is provided by the CTV provider that routes TV channels to the TV and Internet service to the computer or the wireless router if you want to install a WI- FI network. You can watch TV and access Internet and its services simultaneously. Very fast connection up to 8 Mbps and may reach up to 50 Mbps in case businesses want speed beyond what is offered for the public. Slightly higher cost than DSL Very reliable (not affected by weather condition. Satellite access: direct satellite access is provided by many companies that operate and manage satellites like HughesNet, My Blue Dish and Wild blue in the USA. Provide fast Internet in rural areas where only dial-up connection or no connection at all is available. Always ON connection Speed may go up to 18 Mbps. Very reliable Internet access Most expensive Internet service. DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 29

30 VPN (Virtual Private Network) Very important business network that use client server topology May have partly installed local structure. Operates using public networks (mainly the Internet) to exchange private data and make private communications To enforce and enhance communication security a protocol known as Tunneling protocol is used. Tunneling protocol usually does the following: Authenticate the client requesting communication to the VPN Create a secured tunnel (pathway). Complete and control the communication thru that tunnel. VPN is used by businesses to create connection possibilities for their Intranet and Extranet as we will see below. DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 30

31 Intranet Internetwork of many private networks in a company designed to accommodate teamwork and enhance communication and file sharing in a company Uses the Internet protocol TCP/IP Hi security network in a business. Only authorized executives, managers and employees can access it (no outsiders allowed in) An Intranet consists of: Internal system Database loaded with important information and news about the company and its working environment. Websites and some other services as needed. Secured and firewalled Internet access VPN connection to support remote access for company s staff. DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 31

32 Extranet Internetwork like Intranet but with strictly controlled outside access Use VPN (Virtual Private Network) to connect with another network in a different organization. Extranets are widely used by medium and large companies because of the simplicity and convenience they add to business customer relationship and easiness of communication between businesses. DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 32

33 VAN (Value Added Network) considered as a competitor to the post office for business documents and file exchange between businesses. Privately owned highly secured network using private communication media Provides specific services known as VAN services like legal service or translation or accessing special database. Handles electronic mail and file transfer between businesses like EDI (Electronic Data Interchange) transactions. Businesses lease lines to connect to the network and need to install specific software for this purpose. Internet replaced many VANs lately and successfully introduced itself as much efficient and economic tool to replace the VAN. VAN use remains popular between businesses that are seeking high security level when exchanging files DR. NAZIH ABDALLAH - MODERN BUSINESS COMPUTER 33