Computer Networking (Computer Fundamental)

1. Introduction of Networking:

A set /group of distributed intelligence machine that share data/information/communication through any /line cable without cable that is called network. (वितरित खुफिया मेशिनको सेट / समूह जसले डेटा / जानकारी / सञ्चार साझेदारी गर्दछ कुनै पनि / लाइन केबल मार्फत, केबल बिना नेटवर्क भनिन्छ।)

Types of Network:

➤ LAN (Local Area Network): A computer network spanned inside a building and operated under the single administrator system that is local area network. (एक कम्प्युटर नेटवर्क भवन भित्र फ्याँकिएको छ र एकल प्रशासक प्रणाली अन्तर्गत सञ्चालन हुन्छ जुन स्थानीय क्षेत्र नेटवर्क हो।)

➤ MAN (Metropolitan Area Network): The network that interconnected user with cable in geographical area of nay one region to another region/ city that is called Metropolitan area network. (नेटवर्क जुन प्रयोगकर्तालाई नाभिको एक भौगोलिक क्षेत्रमा अर्को क्षेत्र / शहरमा केबलको साथ जोड्दछ जुन मेट्रोपोलिटन क्षेत्र नेटवर्क भनिन्छ।)

➤ WAN (Wide Area Network): A wide area network such as which span a large geographical area such as one country to another country. It uses satellite technology. (विस्तृत क्षेत्र नेटवर्क जस्तै: ठूलो भौगोलिक क्षेत्र जसरी एउटा देशबाट अर्को देशमा विस्तार हुन्छ। यसले उपग्रह प्रविधि प्रयोग गर्दछ।)

2. E-mail/Internet/Intranet/Extranet/WWW:

E-mail: A services which allow us to send and receive element massage over the internet. E-mail called electronic mail. (एक सेवा जसले हामीलाई इन्टरनेटमा एलिमेन्ट message पठाउन र प्राप्त गर्न अनुमति दिँदछ। इ-मेललाई इलेक्ट्रॉनिक मेल भनिन्छ।)

E-mail Address: Each e-mail is signed a unique name for his e-mail account this name is known a E-mail address. Each user have different e-mail address which not match anyone. E-mail name are not allowed space and capital latter. E.g. awasthimohan21@gmail.com (प्रत्येक इ-मेलमा आफ्नो ई-मेल खाताको लागि एक अद्वितीय नाममा हस्ताक्षर हुन्छ जुन यो नामलाई इ-मेल ठेगाना भनेर चिनिन्छ। प्रत्येक प्रयोगकर्तासँग फरक ईमेल ठेगाना हुन्छ जुन कसैसँग मेल खाँदैन। इ-मेल नाम खाली ठाउँ र ठूला अक्षर पछि अनुमति छैन।)

Internet: Internet is a worldwide network that contain vast collection of information and resource available to your computer. It is network of network. (इन्टर्नेट एक विश्वव्यापी नेटवर्क हो जुन तपाईंको कम्प्युटरमा उपलब्ध जानकारी र संसाधनहरूको विशाल संग्रह हुन्छ। यो नेटवर्क को नेटवर्क हो।)

Intranet: Intranet is a private network (LAN) for use by user in network. This is network that is not available to the world outside of the internet. Limited user of Company. It is own server and firewall. (इन्ट्रानेट एक निजी नेटवर्क (LAN) नेटवर्कमा प्रयोगकर्ता द्वारा प्रयोगको लागि हो। यो नेटवर्क हो जुन ईन्टरनेट बाहिरको संसारमा उपलब्ध छैन। कम्पनीको सीमित उपयोगकर्ता। यो आफ्नै सर्वर र फायरवाल हो।)

Extranet: This refers to network within an organization  using internet to connect the outside in controlled. It is opener firm supplier and customer. (यसले बाह्य नियन्त्रित जडान गर्न इन्टरनेट प्रयोग गर्ने संस्था भित्रको नेटवर्क बुझाउँछ। यो ओपनर फर्म आपूर्तिकर्ता र ग्राहक हो।)

Internet browsers:

Web browser: The software is used to access internet. Internet client software designed for to access retrieve and view document/information on the internet/website. (सफ्टवेयर इन्टरनेट पहुँच गर्न प्रयोग गरीन्छ। इन्टरनेट ग्राहक सफ्टवेयर पुन: प्राप्ति गर्न र इन्टरनेट / वेबसाइट मा कागजात / जानकारी हेर्नका लागि डिजाइन गरिएको।) E.g. Mosaic, Microsoft edge, Internet explorer, opera, Mozilla, safari, google chrome, Netscape, lynx.

Search engine: The search engine a tool to locate /find /search information or resource in website /internet which can search the link file page on internet. (खोजी इन्जिन एक उपकरण खोज्न / खोज जानकारी वा स्रोत / वेबसाइट / इन्टरनेटमा श्रोत जसले इन्टरनेटमा लिंक फाइल पृष्ठ खोजी गर्न सक्छ।)

E.g. google.com, yahoo.com, bing.com, info.com, excite.com, ask.com, inkomi.com, lycos.com, altavista.com etc.

E-mail server: A mail server is a computer system that sends and receives email. E.G. gmail.com, hotmail.com, msn.com, yahoomail.com.

IP Address: 

➤ An IP address is unique address of particular computer other network devices on particular network. 

➤ It is part of internet. 

➤ Identifier of computer /devices on TCP/IP network.

➤ Protocols are based on IP address.

➤ Internet IP address 32 bit (4 bytes) long.

➤ The IP address is unique set of group (8 bit).

➤ E.g. 254.180.68.150

Subnet mask: 

➤ 32 bit logical organization.

➤ A subnet mask is a number that defines a range of IP address available within a network.

➤ Communication of network address and host address.

➤ E.g. 255.255.255.0

Network Media: Network transmission device connect/provide data and receive data/information that media is called transmission media.

1. Guided media: A computer that is connected with another with cable physical media that is called guided media media/bound cable transmission media.

types of guided media:

1. Twisted pair cable:

➤  A twisted pair cable is mode of two plastic insulated copper wire twisted together form a single media.

➤ Set up 4 pair = 8 wire

➤ connecter media RJ-45 connecter

➤ Used in LAN (maximum)

➤ Reduced noise.

2. Cereal cable: 

➤ Coaxial cabling has a single copper conductor at its center.

➤ The coaxial cable has high frequency than twisted pair cable.

➤ It has 450 MBPS bandwidth

➤ RG-59(TV), RG-58 (thin Ethernet)

➤ RG 11 (Thick Ethernet)

➤ Coaxial cable use the BNC connecter and T connecter.

3. Fiber optical cable: 

➤ A cable with central glass tube cupper with protect shield which transmit data using photos is fiber optical cable.

➤ It works on the laser beam (light technology)

➤ It made with high quality glass and plastic.

➤ Fastest cable media (technology)

➤ Electromagnetic technology

➤ 200 MBPS - 26 km- Speed

➤ Fiber optic cable are two types: Single mode and Multimode.

Connector: SC, ST, MT, RJ, un-direction, bi-direction both

1. Unguided media:

    ➤ The media is used to connect computer without cable and without any physical media.

    ➤ wireless media

Types of unguided media:

➤ Infra - Red: It is allow computing device to communicate via-short range wireless signal, infra-ray, bidirectional, speed 1-2 MBPS E.g. TV- Remote

➤ Radio wave: The electro-magnetic radiation of frequency ranging from 30 KHZ - 300 GHZ through air. It connect similar/state line one transmitter from another E.g. mobile network tower.

➤ Microwave: It transmits data in same/similar/ particular device/ station. It space larger than radio wave. 1 GHZ - 30 GHZ speed, it transmit data by antenna E.g. Dish home.

 

➤ Wi-Fi: Popular Technology to exchange data /computer networking internet connect. Used in radio wave.

Network Architecture:

➤ Two or more computer are connected to established communication in network that are a physical connection that is called network architecture. (दुई वा अधिक कम्प्युटरहरू नेटवर्कमा स्थापित संचारमा जडित छन् जुन एक भौतिक जडान हो जसलाई नेटवर्क आर्किटेक्चर भनिन्छ।)

Types of Architecture:

➤  OSI (Open System Interconnection): It is most popular communication system, OSI developed by ISO company, It has 7 Layer (Application layer, Presentation layer, Session layer, Transport layer, network layer, data link layer, physical layer)

➤ IBM Network: Computer networking architecture which developed by IBM, It used the protocol, it created the set of rule for transfer data.

Network Model:

1. Client server network model:

    ➤ This model one server computer and many client computers connected, server is more powerful which star whole data and authority.

2. Peer to Peer network model:

    ➤ It has more computer but all are powerful and similar. It has no server work both client and server operations.

 Network Topology:

➤ It is used in LAN technology.

➤ It is also called physical arrangement of computer in network.

Types of Topology: more details

1. Bus Topology: 

    ➤ Bus network is topology is contains many computer with in single line/cable. Cable not used more than other Topology.

2. Ring Topology: Each device or computer is connected one to another computer in the shape of closed loop (ring).

 

3. Star Topology: It network used the any devices (Hub/Switch) in central point of computer.

4. Tree Topology: The various terminal and computer are link/connect to a main computer/server in network.

5. Hybrid Topology: It is portly combination of star and bus with ring topology.

6. Mesh Topology: This network all point/ node are connected each other all computer not depended one computer

Communication Mode:

1. Simplex: It transmit data one way one side. (यसले डाटा एक तर एक तर्फ प्रसारित गर्दछ।)

2. Half duplex: It transmit data both side /two way but in one time can't it transmit one time one way. (यसले दुबै पक्ष / दुई तर्फ डाटा प्रसारण गर्दछ तर एक पटकमा यसले एक पटक एक पटक प्रसारित गर्न सक्दैन।)

3. Full duplex: A system transmit data simultaneously both direction over channel. Transmit data two way say in same time. (एक प्रणाली डाटा एक साथ दुबै दिशामा च्यानल प्रसारण गर्दछ। डाटा प्रसारण दुई तरीकाले एकै समयमा भन्नुहोस्।)

Firewall:

➤ A firewall is hardware or software that helps control the spread of malicious software on your network and helps to protect your devices when you use the internet. (फायरवाल हार्डवेयर वा सफ्टवेयर हो जुन तपाईंको नेटवर्कमा मालिसियस सफ्टवेयरको प्रसारलाई नियन्त्रण गर्न मद्दत गर्दछ र जब तपाईं इन्टरनेट प्रयोग गर्नुहुन्छ तपाईंको उपकरणहरूको सुरक्षा गर्न मद्दत गर्दछ।)

Dial-Up Networking:

➤ The DUN connects the system to the ISP, which than provides the system a certain IP address and internet gateway address to be connected to and be a part of the network. (DUN ले प्रणालीलाई ISP मा जोड्दछ, जसले प्रणालीलाई जडान हुन र नेटवर्कको एक हिस्सा हुन एक निश्चित IP ठेगाना र इन्टरनेट गेटवे ठेगाना प्रदान गर्दछ।)