What Everyone Must know about Networking?
Table of Content:
1.Networking Basics
2.Network Types
3.Network Topologies
4.Network Devices
5.Transmission Modes
6.Digital Transmission
7.Transmission Media
8.How Internet Works
9.IP Addressing IPv4 & IPv6
10.Subnet Mask, MAC, DHCP & DNS
11.WLAN & WPAN Networks
12.OSI Model
13.TCP/IP Model
14.TCP & UDP
15.ARP & RARP
16.CSMA/CA & CSMA/CD
17.Proxy & VPN
18.Server & Datacenter
19. Network Security
20. NAS & NAT
21. RAID (Redundant Array of Independent Disk)
22. Sharing Folder in Network
23. TELNET in Network
24. Remote Desktop Connection
25. Windows Remote Assistance
26. FTP in Network
27. Configuring Network
28. Configuring Router
29. Protocols You need to know
30. Networking Commands you must know
The Networking Article of Your Dreams:
NETWORK:
A network consists of two or more computers that are linked in order to share resources, exchange files or communication. The computers on a network may be linked through cables, telephone lines, radio waves, satellites, or infrared light beams.
NETWORKING:
Networking, also known as computer networking, is the practice of transporting and exchanging data or information & having communication between connected nodes over a shared medium.
INTERNET:
Collection of Networks is Internet. The first workable prototype of the Internet came in the late 1960s with the creation of ARPANET, or the Advanced Research Projects Agency Network. Which was designed for US Defence. Later Sir Tim Berners lee introduced WWW concept and starts web.
MESSAGE / TOKEN
When one of the systems on the network has the “token,” it can send information to the other computers. Since there is only one token for each token-ring network, only one computer can send data at a time. It verify that the target receiver is present or not before sending the data from sender.
NETWORK ARCHITECTURE:
- Peer to Peer Model
2. Client-Server Model
Peer to Peer Model:
Client-Server Model:
Peer to Peer VS Client-Server Model:
Basic Types of Networks
1. Personal Area Network (PAN)
2. Local Area Network (LAN)
3. Wide Area Network (WAN)
4. Wireless Local Area Network (WLAN)
5. Campus Area Network (CAN)
6. Metropolitan Area Network (MAN)
7. Storage Area Network (SAN)
8. Enterprise Private Network (EPN)
9. Virtual Private Network (VPN)
Personal Area Network (PAN)
PAN is the most basic type of computer network. This network is restrained to a single person, PAN offers a network range of 10 meters from a person to the device providing communication.
Local Area Network (LAN)
LAN is the most frequently used network. A LAN is a computer network that connects computers together through a common communication path, contained within a limited area, A LAN encompasses two or more computers connected over a server. The two important technologies involved in this network are Ethernet and Wi-fi.
3. Wide Area Network (WAN)
WAN is a type of computer network that connects computers over a large geographical distance through a shared communication path. It is not restrained to a single location but extends over many locations. WAN can also be defined as a group of local area networks that communicate with each other.
4. Wireless Local Area Network (WLAN)
WLAN is a type of computer network that acts as a local area network but makes use of wireless network technology like Wi-Fi. This network doesn’t allow devices communicating over physical cables like in LAN, but allows devices to communicate wirelessly.
5. Campus Area Network (CAN)
CAN is bigger than a LAN but smaller than a MAN. This is a type of computer network which is usually used in places like a school or college. This network covers a limited geographical area that is, it spreads across several buildings within the campus.
6. Metropolitan Area Network (MAN)
A MAN is larger than a LAN but smaller than a WAN. This is the type of computer network that connects computers over a geographical distance through a shared communication path over a city, town or metropolitan area.
7. Storage Area Network (SAN)
SAN is an abbreviation of the Storage Area Network. Storage Area Network is a dedicated, specialized, and high-speed network which provides block-level data storage. It delivers the shared pool of storage devices to more than one server.
8. Enterprises Private Network (EPN)
EPN is a type of computer network mostly used by businesses that want a secure connection over various locations to share computer resources.
9. Virtual Private Network (VPN)
A virtual private network extends a private network across a public network and enables users to send and receive data across shared or public networks as if their computing devices were directly connected to the private network.
Network Topologies
Basic Types of Network Topologies
- Bus Topology
- Star Topology
- Ring Topology
- Tree Topology
- Mesh Topology
- Hybrid Topology
- Daisy Chain Topology
1. Bus Topology
The bus topology is designed in such a way that all the stations are connected through a single cable known as a backbone cable. The backbone cable is considered as a “single lane” through which the message is broadcast to all the stations.
2. Star Topology
Star topology is an arrangement of the network in which every node is connected to the central hub, switch or a central computer. The central computer is known as a server, and the peripheral devices attached to the server are known as clients.
3. Ring Topology
Ring topology is like a bus topology, but with connected ends. The node that receives the message from the previous computer will retransmit to the next node.
The data flows in a single loop continuously known as an endless loop. The most common access method of the ring topology is token passing.
4. Tree Topology
Tree topology combines the characteristics of bus topology and star topology. A tree topology is a type of structure in which all the computers are connected with each other in hierarchical fashion. If the central hub gets fails the entire system fails.
5. Mesh Topology
In this type of topology, a host is connected to one or multiple hosts.This topology has hosts in point-to-point connection with every other host or may also have hosts which are in point-to-point connection to few hosts only.
Two types Full Mesh Topology & Partially Mesh.
6. Hybrid Topology
The combination of various different topologies is known as Hybrid topology. When two or more different topologies are combined together is termed as Hybrid topology and if similar topologies are connected with each other will not result in Hybrid topology.
7. Daisy Chain Topology
This topology connects all the hosts in a linear fashion. Similar to Ring topology, all hosts are connected to two hosts only, except the end hosts. Means if the end hosts in daisy chain are connected then it represents Ring topology.
Network Devices
Basic Types of Network Devices
- NIC Card
- Hub
- Switch
- Router
- Repeater
- Modem
- Bridge
- Gateway
- Access Point
- Server
1. NIC Card
NIC or network interface card is a network adapter that is used to connect the computer to the network. bit has a unique id that is written on the chip, and it has a connector to connect the cable to it. The cable acts as an interface between the computer and router.
2. Hub
A hub is basically a multiport repeater. A hub connects multiple wires coming from different branches, for example, the connector in star topology which connects different stations. Hubs cannot filter data, so data packets are sent to all connected devices. they do not have the intelligence to find out the best path for data packets which leads to inefficiencies and wastage.
3. Switch
A switch is a hardware device that connects multiple devices on a computer network. A Switch contains more advanced features than Hub. A Switch does not broadcast the message to the entire network like Hub. It determines the device to whom the message is to be transmitted. Therefore, we can say that switch provides a direct connection between the source and destination. It increases the speed of the network.
4. Router
A router is a device like a switch that routes data packets based on their IP addresses. It is used to receive, analyze and forward the incoming packets to another network. A router forwards the packet based on the information available in the routing table.
5. Repeater
Its job is to regenerate the signal over the same network before the signal becomes too weak or corrupted so as to extend the length to which the signal can be transmitted over the same network. An important point to be noted about repeaters is that they do not amplify the signal. When the signal becomes weak, they copy the signal bit by bit and regenerate it at the original strength.
6. Modem
It stands for Modulator/Demodulator. It converts the digital data into an analog signal over the telephone lines. It allows the computer to connect to the internet over the existing telephone line.
• Standard PC modem or Dial-up modem
• Cellular Modem
- Cable modem
7. Bridge
A bridge is a repeater, with add on the functionality of filtering content by reading the MAC addresses of source and destination. It is also used for interconnecting two LANs working on the same protocol. It has a single input and single output port.
Types of Bridges
v Transparent Bridge: -
These are the bridge in which the stations are completely unaware of the bridge’s existence
v Translational Bridge: -
A type of bridge that interconnects two different types of LAN protocols, such as Ethernet and Token Ring.
v Source Routing Bridge: -
A type of bridge that interconnects 2 different types of LAN protocols, such as Ethernet and Token Ring.
v Remote type Bridge: -
A device that connects two LAN segments together that are in geographically dispersed locations. It connects LANs via a WAN.
8. Gateway
A gateway is a network node that forms a passage between two networks operating with different transmission protocols.
The gateway converts information, data or other communications from one protocol or format to another. A router may perform some of the functions of a gateway.
9. Access Point
An access point is a device that creates a wireless local area network, or WLAN, usually in an office or large building. An access point connects to a wired router, switch, or hub via an Ethernet cable and device that allows other Wi-Fi devices to connect to a wired network.
10. Server
A server is a computer or system that provides resources, data, services, or programs to other computers, known as clients, over a network. In theory, whenever computers share resources with client machines they are considered servers. Typical servers are database servers, file servers, mail servers, print servers, web servers, game servers, and application servers.
Transmission Modes
The way in which data is transmitted from one device to another device is known as transmission mode. Each communication channel has a direction associated with it, and transmission media provide the direction. Therefore, the transmission mode is also known as a directional mode.
Simplex-mode Transmission
In Simplex mode, the data flows in one direction. This transmission mode is not very popular as mainly communications require the two-way exchange of data. Keyboard and Monitor are the examples of the simplex mode as a keyboard can only accept the data from the user and monitor can only be used to display the data on the screen. The main advantage of the simplex mode is that the full capacity of the communication channel can be utilized during transmission.
Half-Duplex Transmission
In a Half-duplex channel the station can transmit and receive the data as well. Messages flow in both the directions, but not at the same time. A Walkie-talkie is an example of the Half-duplex mode. In Walkie-talkie, one party speaks, and another party listens. After a pause, the other speaks and first party listens. The entire bandwidth of the communication channel is utilized in one direction at a time.
Full-Duplex Transmission
In Full duplex mode, the data flow in both the directions. Both the stations can send and receive the message simultaneously. The Full-duplex mode is the fastest mode of communication between devices. The most common example of the full-duplex mode is a telephone network. When two people are communicating with each other by a telephone line, both can talk and listen at the same time.
Digital Transmission
Data can be represented either in analogue or digital form. The computers used the digital form to store the information. Therefore, the data needs to be converted in digital form so that it can be used by a computer.
Digital to Digital Conversion?
Digital-to-digital encoding is the representation of digital information by a digital signal. When binary 1s and 0s generated by the computer are translated into a sequence of voltage pulses that can be propagated over a wire, this process is known as digital-to-digital encoding.
Three forms:
Unipolar
Digital transmission system sends the voltage pulses over the medium link such as wire or cable. The polarity of each pulse determines whether it is positive or negative. In Unipolar Encoding, ‘1’ is considered as a high voltage and ‘0’ is considered as a zero voltage.
Polar
Polar encoding is an encoding scheme that uses two voltage levels: one is positive, and another is negative. By using two voltage levels, an average voltage level is reduced, and the DC component problem of unipolar encoding scheme is alleviated.
• Polar NRZ
• Polar RZ
Polar NRZ
Polar RZ
Bipolar
If the first 1 bit is represented by positive amplitude, then the second 1 bit is represented by negative voltage, third 1 bit is represented by the positive amplitude and so on. This alternation can also occur even when the 1bits are not consecutive.
AMI (Alternate Mark Inversion) The Binary 0 gets represented by a neutral voltage. On the other hand, alternating negative and positive voltages represent the Binary 1s.
Pseudo ternary Here, we encode the bit 1 as a zero voltage, while we encode the bit 0 as alternating negative and positive voltages. It means that this one is exactly the opposite of the AMI scheme. For example, Data = 010010.
Transmission Media
Transmission media is a communication channel that carries the information from the sender to the receiver. Data is transmitted through the electromagnetic signals.
Bandwidth: -
The greater the bandwidth of a medium, the higher the data transmission rate of a signal.
Transmission impairment: — When the received signal is not identical to the transmitted one due to the transmission impairment. quality of the signals will get destroyed due to transmission impairment.
Interference: — An interference is defined as the process of disrupting a signal when it travels over a communication medium on the addition of some unwanted signal.
Attenuation means the loss of energy, strength of the signal decreases with increasing the distance
Distortion occurs when there is a change in the shape of signal. This type of distortion is examined from different signals having diff frequencies.
Noise is When data is travelled over a transmission medium, some unwanted signal is added to it
Classification of Transmission Media?
Guided Media
It is defined as the physical medium in which the signals are transmitted. also known as Bounded media.
What is a Cable?
An electrical cable is an assembly of one or more wires running side by side or bundled, which is used to carry electric current. A cable assembly is the composition of one or more electrical cables and their corresponding connectors.
1. Twisted Pair Cable
Twisted-pair cable is a type of cabling that is used for telephone communications and most modern Ethernet networks. A pair of wires forms a circuit that can transmit data. The pairs are twisted to provide protection against crosstalk, the noise generated by adjacent pairs having RJ-11 & RJ-45 Jacks.
Two Types :-
- STP (Shielded Twisted Pair Cable)
2. UTP (Unshielded Twisted Pair Cable)
Ethernet Port
• Connects to a network and high speed Internet upto 100baseT.
• Known as RJ-45 Port which use RJ-45 Jack as Interface
- This port resides on an Ethernet Card.
What are RJ connectors?
RJ Connectors are a family of push-and-click connectors for twisted-pair wiring in telephone and network wiring. RJ stands for Registered Jack. RJ types define both a jack or receptacle (female) and a plug (male) type of connector.
The most common types of RJ connectors are as follows:
RJ-11 connector: A 4-wire or 6-wire telephone-type connector
RJ-45 connector: An 8-wire telephone-type connector
RJ-48 connector: An 8-wire telephone-type connector
2. Patch Cables
Patch cable is often called a straight through cable. In other words, patch cable does not change or swap along its way. Both ends use the same wiring standard: T-568A or T-568B.
Straight Tip vs Crosstalk
Patch Cables vs. Crossover Cable: When to Use?
Scenario 1: PC to PC
Scenario 2: PC to Switch to PC
Scenario 3: PC to Switch to Switch to PC
3. Coaxial Cable
Coaxial cable is commonly used by cable operators, telephone companies, and internet providers around the world to convey data, video, and voice communications to customers. It has also been used extensively within homes.
BNC Connector
Bayonet Neill–Concelman BNC connector is a series of connectors used for connecting thinnet coaxial cabling to various networking components.
4. Optic Fibre Cable
Fibre optics is a modern technology used mostly in the telecommunication industry to transmit information digitally as pulses of light through strands of fibre made of glass.Also known as Optical fibres, these strands are about the diameter of a human hair follicle. When bundled into an optical fibre cable, they can transmit data in volumes faster than other mediums over really long distances.
Subscriber Connector SC
This Connector is for structural cabling it is used for high speed
And for single mode fibre cabling
Straight Tip ST
This Connector is for structural cabling it is used for high speed
And for Multi mode fibre cabling
Unguided Media
They transmits the electromagnetic waves without using physical medium.it is also known as wireless transmission.
Radio Waves
Radio waves at lower frequencies can travel through walls whereas higher RF can travel in straight line and bounce back.The power of low frequency waves decreases sharply as they cover long distance. High frequency radio waves have more power. The range in frequencies of radio waves is from 20kHz 300Hz.
Applications
• television and FM and AM radio broadcasts
• military communications
- Radio Control Car
Microwaves
• Microwaves travel in straight lines, and so the transmitter and receiver stations should be accurately aligned to each other. Microwaves are unidirectional
• Microwaves electromagnetic waves having frequency in the range from 1GHz to 1000 GHz.
Applications
• Cellular phones
• 3G, 4G or 5G Network
• Satellites
• Wireless LAN
- Wireless PAN
Infrared
Infrared waves are those between the frequencies 300GHz and 400THz in the electromagnetic spectrum. Their wavelengths are shorter than microwaves but longer than visible light. Infrared propagation is line of sight. Range lies bwtween 300 GHz to 400 THz.
Applications
• Remote controls for television, stereos and other appliances.
• Wireless modem, keyboard, mouse, printer etc
• Night vision systems
• Motion detectors
- MRI
How Internet Works
IP Addressing IPv4 & IPv6
What is IP Address?
An Internet Protocol address is a numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication. An IP address serves two main functions: host or network interface identification and location addressing.
IP Addressing IPv4
• An IP address basically a 32-bit address that uniquely universally defines connection of host or a router to the Internet. IP address is unique.
• Introduced by IANA (Internet Assigned Numbers Authority).
• 32 bit is divided into 4 equal parts of 8–8 bits separated by dotted decimal notation. It is in the range of minimum 0.0.0.0 to 255.255.255.255.
• Each 8 bit group is known by OCTET.
Various IP classes
IP has five different classes differentiated by characteristics.
◦ Class-A ranges from 0 to 127
◦ Class-B ranges from 128 to 191
◦ Class-C ranges from 192 to 223
◦ Class-D ranges from 224 to 239
◦ Class-E ranges from 240 to 255
First Octet is defines the class of particular IP e.g. — 128.11.3.31 is follow in class –B
127.0.0.0 to 127.255.255.255 is a range of look back IP.
Class-A
Class A addresses only include IP starting from 1.x.x.x to 126.x.x.x only. The IP range 127.x.x.x is reserved for loopback IP addresses.
The default subnet mask for Class A IP address is 255.0.0.0 which implies that Class A addressing can have 126 networks (27–2) and 16777214 hosts (224–2).
Class B
Class B IP Addresses range from 128.0.x.x to 191.255.x.x. The default subnet mask for Class B is 255.255.x.x.
Class B has 16384 (214) Network addresses and 65534 (216–2) Host addresses.
Class C
Class C IP addresses range from 192.0.0.x to 223.255.255.x. The default subnet mask for Class C is 255.255.255.x. Class C gives 2097152 (221) Network addresses and 254 (28–2) Host addresses.
Class-D
Class D has IP address range from 224.0.0.0 to 239.255.255.255. Class D is reserved for Multicasting. In multicasting data is not destined for a particular host, that is why there is no need to extract host address from the IP address, and Class D does not have any subnet mask.
Class-E
This IP Class is reserved for experimental purposes only for R&D or Study. IP addresses in this class ranges from 240.0.0.0 to 255.255.255.254. Like Class D, this class too is not equipped with any subnet mask.
IP Addressing IPv6
• An IP address basically a 128-bit address that uniquely universally defines connection of host or a router to the Internet. IP address is unique.
• Introduced by IANA (Internet Assigned Numbers Authority).
• total of 4,294,967,296 unique IP addresses can be assigned to hosts.
• IP is like 2001:db8:1234::f350:2256:f3dd/64
• It supports Unicast. Telecast & Multicast.
- It doesn’t have Classes like ipv4
Subnet Mask, MAC, DHCP & DNS
What is Subnet Mask?
A subnet mask is a 32-bit number that segments an existing IP address in a TCP/IP network. It is used by the TCP/IP protocol to determine whether a host is on the local subnet or on a remote network. Subnet mask divides the IP address into a network address and host address, hence to identify which part of IP address is reserved for the network and which part is available for host use.
MAC Address
The Media Access Control (MAC) address is just as important as the IP address. The MAC address is a unique value associated with the network adapter (NIC). MAC addresses are known as the hardware addresses or physical addresses. They uniquely identify the adapter on the LAN.
MAC Address
DHCP
● Dynamic Host Configuration Protocol (DHCP)
○ From 1993
○ An extension of BOOTP, very similar to DHCP
○ Same port numbers as BOOTP
○ Extensions:
■ Supports temporary allocation (“leases”) of IP addresses
■ DHCP client can acquire all IP configuration parameters needed to operate
○ DHCP is the preferred mechanism for dynamic assignment of IP addresses
○ DHCP can interoperate with BOOTP clients.
APIPA
APIPA stands for Automatic Private IP Addressing (APIPA). It is a feature or characteristic in operating systems (eg. Windows) which enables computers to self-configure an IP address and subnet mask automatically when their DHCP(Dynamic Host Configuration Protocol) server isn’t reachable
DNS
DNS stands for Domain Name System. DNS is a service that translates the domain name into IP addresses. This allows the users of networks to utilize user-friendly names when looking for other hosts instead of remembering the IP addresses.
(The inverse domain is used for mapping an address to a name.)
(Generic Domains defines the registered hosts according to their generic behaviour.)
(The format of country domain is same as a generic domain)
Importance of DNS
WLAN & WPAN Networks
WLAN
A wireless LAN is a wireless computer network that links two or more devices using wireless communication to form a local area network within a limited area such as a home, school, computer laboratory, campus, or office building.
Wi-Fi
What is Wi-Fi
Short for “Wireless Fidelity”
A trademark of the Wi-Fi Alliance
The brand name for products using the IEEE 802.11 family of standards
Commonly used for “wireless local area network” (WLAN)
WPAN
A personal area network is a computer network for interconnecting electronic devices within an individual person’s workspace. A WPAN provides data transmission among devices such as computers, smartphones, tablets and personal digital assistants.
Bluetooth
Wireless Personal Area Networks (WPAN)
Design goal
Cable replacement
Low cost
Low power
Small size
For mobile devices
OSI Model
INTRODUCTION
The OSI Model (Open Systems Interconnection Model) is a conceptual framework used to describe the functions of a networking system. The OSI model characterizes computing functions into a universal set of rules and requirements in order to support interoperability between different products and software
What Everyone Must know about Networking?
Table of Content:
1.Networking Basics
2.Network Types
3.Network Topologies
4.Network Devices
5.Transmission Modes
6.Digital Transmission
7.Transmission Media
8.How Internet Works
9.IP Addressing IPv4 & IPv6
10.Subnet Mask, MAC, DHCP & DNS
11.WLAN & WPAN Networks
12.OSI Model
13.TCP/IP Model
14.TCP & UDP
15.ARP & RARP
16.CSMA/CA & CSMA/CD
17.Proxy & VPN
18.Server & Datacenter
19. Network Security
20. NAS & NAT
21. RAID (Redundant Array of Independent Disk)
22. Sharing Folder in Network
23. TELNET in Network
24. Remote Desktop Connection
25. Windows Remote Assistance
26. FTP in Network
27. Configuring Network
28. Configuring Router
29. Protocols You need to know
30. Networking Commands you must know
The Networking Article of Your Dreams:
NETWORK:
A network consists of two or more computers that are linked in order to share resources, exchange files or communication. The computers on a network may be linked through cables, telephone lines, radio waves, satellites, or infrared light beams.
NETWORKING:
Networking, also known as computer networking, is the practice of transporting and exchanging data or information & having communication between connected nodes over a shared medium.
INTERNET:
Collection of Networks is Internet. The first workable prototype of the Internet came in the late 1960s with the creation of ARPANET, or the Advanced Research Projects Agency Network. Which was designed for US Defence. Later Sir Tim Berners lee introduced WWW concept and starts web.
MESSAGE / TOKEN
When one of the systems on the network has the “token,” it can send information to the other computers. Since there is only one token for each token-ring network, only one computer can send data at a time. It verify that the target receiver is present or not before sending the data from sender.
NETWORK ARCHITECTURE:
- Peer to Peer Model
2. Client-Server Model
Peer to Peer Model:
Client-Server Model:
Peer to Peer VS Client-Server Model:
Basic Types of Networks
1. Personal Area Network (PAN)
2. Local Area Network (LAN)
3. Wide Area Network (WAN)
4. Wireless Local Area Network (WLAN)
5. Campus Area Network (CAN)
6. Metropolitan Area Network (MAN)
7. Storage Area Network (SAN)
8. Enterprise Private Network (EPN)
9. Virtual Private Network (VPN)
Personal Area Network (PAN)
PAN is the most basic type of computer network. This network is restrained to a single person, PAN offers a network range of 10 meters from a person to the device providing communication.
Local Area Network (LAN)
LAN is the most frequently used network. A LAN is a computer network that connects computers together through a common communication path, contained within a limited area, A LAN encompasses two or more computers connected over a server. The two important technologies involved in this network are Ethernet and Wi-fi.
3. Wide Area Network (WAN)
WAN is a type of computer network that connects computers over a large geographical distance through a shared communication path. It is not restrained to a single location but extends over many locations. WAN can also be defined as a group of local area networks that communicate with each other.
4. Wireless Local Area Network (WLAN)
WLAN is a type of computer network that acts as a local area network but makes use of wireless network technology like Wi-Fi. This network doesn’t allow devices communicating over physical cables like in LAN, but allows devices to communicate wirelessly.
5. Campus Area Network (CAN)
CAN is bigger than a LAN but smaller than a MAN. This is a type of computer network which is usually used in places like a school or college. This network covers a limited geographical area that is, it spreads across several buildings within the campus.
6. Metropolitan Area Network (MAN)
A MAN is larger than a LAN but smaller than a WAN. This is the type of computer network that connects computers over a geographical distance through a shared communication path over a city, town or metropolitan area.
7. Storage Area Network (SAN)
SAN is an abbreviation of the Storage Area Network. Storage Area Network is a dedicated, specialized, and high-speed network which provides block-level data storage. It delivers the shared pool of storage devices to more than one server.
8. Enterprises Private Network (EPN)
EPN is a type of computer network mostly used by businesses that want a secure connection over various locations to share computer resources.
9. Virtual Private Network (VPN)
A virtual private network extends a private network across a public network and enables users to send and receive data across shared or public networks as if their computing devices were directly connected to the private network.
Network Topologies
Basic Types of Network Topologies
- Bus Topology
- Star Topology
- Ring Topology
- Tree Topology
- Mesh Topology
- Hybrid Topology
- Daisy Chain Topology
1. Bus Topology
The bus topology is designed in such a way that all the stations are connected through a single cable known as a backbone cable. The backbone cable is considered as a “single lane” through which the message is broadcast to all the stations.
2. Star Topology
Star topology is an arrangement of the network in which every node is connected to the central hub, switch or a central computer. The central computer is known as a server, and the peripheral devices attached to the server are known as clients.
3. Ring Topology
Ring topology is like a bus topology, but with connected ends. The node that receives the message from the previous computer will retransmit to the next node.
The data flows in a single loop continuously known as an endless loop. The most common access method of the ring topology is token passing.
4. Tree Topology
Tree topology combines the characteristics of bus topology and star topology. A tree topology is a type of structure in which all the computers are connected with each other in hierarchical fashion. If the central hub gets fails the entire system fails.
5. Mesh Topology
In this type of topology, a host is connected to one or multiple hosts.This topology has hosts in point-to-point connection with every other host or may also have hosts which are in point-to-point connection to few hosts only.
Two types Full Mesh Topology & Partially Mesh.
6. Hybrid Topology
The combination of various different topologies is known as Hybrid topology. When two or more different topologies are combined together is termed as Hybrid topology and if similar topologies are connected with each other will not result in Hybrid topology.
7. Daisy Chain Topology
This topology connects all the hosts in a linear fashion. Similar to Ring topology, all hosts are connected to two hosts only, except the end hosts. Means if the end hosts in daisy chain are connected then it represents Ring topology.
Network Devices
Basic Types of Network Devices
- NIC Card
- Hub
- Switch
- Router
- Repeater
- Modem
- Bridge
- Gateway
- Access Point
- Server
1. NIC Card
NIC or network interface card is a network adapter that is used to connect the computer to the network. bit has a unique id that is written on the chip, and it has a connector to connect the cable to it. The cable acts as an interface between the computer and router.
2. Hub
A hub is basically a multiport repeater. A hub connects multiple wires coming from different branches, for example, the connector in star topology which connects different stations. Hubs cannot filter data, so data packets are sent to all connected devices. they do not have the intelligence to find out the best path for data packets which leads to inefficiencies and wastage.
3. Switch
A switch is a hardware device that connects multiple devices on a computer network. A Switch contains more advanced features than Hub. A Switch does not broadcast the message to the entire network like Hub. It determines the device to whom the message is to be transmitted. Therefore, we can say that switch provides a direct connection between the source and destination. It increases the speed of the network.
4. Router
A router is a device like a switch that routes data packets based on their IP addresses. It is used to receive, analyze and forward the incoming packets to another network. A router forwards the packet based on the information available in the routing table.
5. Repeater
Its job is to regenerate the signal over the same network before the signal becomes too weak or corrupted so as to extend the length to which the signal can be transmitted over the same network. An important point to be noted about repeaters is that they do not amplify the signal. When the signal becomes weak, they copy the signal bit by bit and regenerate it at the original strength.
6. Modem
It stands for Modulator/Demodulator. It converts the digital data into an analog signal over the telephone lines. It allows the computer to connect to the internet over the existing telephone line.
• Standard PC modem or Dial-up modem
• Cellular Modem
- Cable modem
7. Bridge
A bridge is a repeater, with add on the functionality of filtering content by reading the MAC addresses of source and destination. It is also used for interconnecting two LANs working on the same protocol. It has a single input and single output port.
Types of Bridges
v Transparent Bridge: -
These are the bridge in which the stations are completely unaware of the bridge’s existence
v Translational Bridge: -
A type of bridge that interconnects two different types of LAN protocols, such as Ethernet and Token Ring.
v Source Routing Bridge: -
A type of bridge that interconnects 2 different types of LAN protocols, such as Ethernet and Token Ring.
v Remote type Bridge: -
A device that connects two LAN segments together that are in geographically dispersed locations. It connects LANs via a WAN.
8. Gateway
A gateway is a network node that forms a passage between two networks operating with different transmission protocols.
The gateway converts information, data or other communications from one protocol or format to another. A router may perform some of the functions of a gateway.
9. Access Point
An access point is a device that creates a wireless local area network, or WLAN, usually in an office or large building. An access point connects to a wired router, switch, or hub via an Ethernet cable and device that allows other Wi-Fi devices to connect to a wired network.
10. Server
A server is a computer or system that provides resources, data, services, or programs to other computers, known as clients, over a network. In theory, whenever computers share resources with client machines they are considered servers. Typical servers are database servers, file servers, mail servers, print servers, web servers, game servers, and application servers.
Transmission Modes
The way in which data is transmitted from one device to another device is known as transmission mode. Each communication channel has a direction associated with it, and transmission media provide the direction. Therefore, the transmission mode is also known as a directional mode.
Simplex-mode Transmission
In Simplex mode, the data flows in one direction. This transmission mode is not very popular as mainly communications require the two-way exchange of data. Keyboard and Monitor are the examples of the simplex mode as a keyboard can only accept the data from the user and monitor can only be used to display the data on the screen. The main advantage of the simplex mode is that the full capacity of the communication channel can be utilized during transmission.
Half-Duplex Transmission
In a Half-duplex channel the station can transmit and receive the data as well. Messages flow in both the directions, but not at the same time. A Walkie-talkie is an example of the Half-duplex mode. In Walkie-talkie, one party speaks, and another party listens. After a pause, the other speaks and first party listens. The entire bandwidth of the communication channel is utilized in one direction at a time.
Full-Duplex Transmission
In Full duplex mode, the data flow in both the directions. Both the stations can send and receive the message simultaneously. The Full-duplex mode is the fastest mode of communication between devices. The most common example of the full-duplex mode is a telephone network. When two people are communicating with each other by a telephone line, both can talk and listen at the same time.
Digital Transmission
Data can be represented either in analogue or digital form. The computers used the digital form to store the information. Therefore, the data needs to be converted in digital form so that it can be used by a computer.
Digital to Digital Conversion?
Digital-to-digital encoding is the representation of digital information by a digital signal. When binary 1s and 0s generated by the computer are translated into a sequence of voltage pulses that can be propagated over a wire, this process is known as digital-to-digital encoding.
Three forms:
Unipolar
Digital transmission system sends the voltage pulses over the medium link such as wire or cable. The polarity of each pulse determines whether it is positive or negative. In Unipolar Encoding, ‘1’ is considered as a high voltage and ‘0’ is considered as a zero voltage.
Polar
Polar encoding is an encoding scheme that uses two voltage levels: one is positive, and another is negative. By using two voltage levels, an average voltage level is reduced, and the DC component problem of unipolar encoding scheme is alleviated.
• Polar NRZ
• Polar RZ
Polar NRZ
Polar RZ
Bipolar
If the first 1 bit is represented by positive amplitude, then the second 1 bit is represented by negative voltage, third 1 bit is represented by the positive amplitude and so on. This alternation can also occur even when the 1bits are not consecutive.
AMI (Alternate Mark Inversion) The Binary 0 gets represented by a neutral voltage. On the other hand, alternating negative and positive voltages represent the Binary 1s.
Pseudo ternary Here, we encode the bit 1 as a zero voltage, while we encode the bit 0 as alternating negative and positive voltages. It means that this one is exactly the opposite of the AMI scheme. For example, Data = 010010.
Transmission Media
Transmission media is a communication channel that carries the information from the sender to the receiver. Data is transmitted through the electromagnetic signals.
Bandwidth: -
The greater the bandwidth of a medium, the higher the data transmission rate of a signal.
Transmission impairment: — When the received signal is not identical to the transmitted one due to the transmission impairment. quality of the signals will get destroyed due to transmission impairment.
Interference: — An interference is defined as the process of disrupting a signal when it travels over a communication medium on the addition of some unwanted signal.
Attenuation means the loss of energy, strength of the signal decreases with increasing the distance
Distortion occurs when there is a change in the shape of signal. This type of distortion is examined from different signals having diff frequencies.
Noise is When data is travelled over a transmission medium, some unwanted signal is added to it
Classification of Transmission Media?
Guided Media
It is defined as the physical medium in which the signals are transmitted. also known as Bounded media.
What is a Cable?
An electrical cable is an assembly of one or more wires running side by side or bundled, which is used to carry electric current. A cable assembly is the composition of one or more electrical cables and their corresponding connectors.
1. Twisted Pair Cable
Twisted-pair cable is a type of cabling that is used for telephone communications and most modern Ethernet networks. A pair of wires forms a circuit that can transmit data. The pairs are twisted to provide protection against crosstalk, the noise generated by adjacent pairs having RJ-11 & RJ-45 Jacks.
Two Types :-
- STP (Shielded Twisted Pair Cable)
2. UTP (Unshielded Twisted Pair Cable)
Ethernet Port
• Connects to a network and high speed Internet upto 100baseT.
• Known as RJ-45 Port which use RJ-45 Jack as Interface
- This port resides on an Ethernet Card.
What are RJ connectors?
RJ Connectors are a family of push-and-click connectors for twisted-pair wiring in telephone and network wiring. RJ stands for Registered Jack. RJ types define both a jack or receptacle (female) and a plug (male) type of connector.
The most common types of RJ connectors are as follows:
RJ-11 connector: A 4-wire or 6-wire telephone-type connector
RJ-45 connector: An 8-wire telephone-type connector
RJ-48 connector: An 8-wire telephone-type connector
2. Patch Cables
Patch cable is often called a straight through cable. In other words, patch cable does not change or swap along its way. Both ends use the same wiring standard: T-568A or T-568B.
Straight Tip vs Crosstalk
Patch Cables vs. Crossover Cable: When to Use?
Scenario 1: PC to PC
Scenario 2: PC to Switch to PC
Scenario 3: PC to Switch to Switch to PC
3. Coaxial Cable
Coaxial cable is commonly used by cable operators, telephone companies, and internet providers around the world to convey data, video, and voice communications to customers. It has also been used extensively within homes.
BNC Connector
Bayonet Neill–Concelman BNC connector is a series of connectors used for connecting thinnet coaxial cabling to various networking components.
4. Optic Fibre Cable
Fibre optics is a modern technology used mostly in the telecommunication industry to transmit information digitally as pulses of light through strands of fibre made of glass.Also known as Optical fibres, these strands are about the diameter of a human hair follicle. When bundled into an optical fibre cable, they can transmit data in volumes faster than other mediums over really long distances.
Subscriber Connector SC
This Connector is for structural cabling it is used for high speed
And for single mode fibre cabling
Straight Tip ST
This Connector is for structural cabling it is used for high speed
And for Multi mode fibre cabling
Unguided Media
They transmits the electromagnetic waves without using physical medium.it is also known as wireless transmission.
Radio Waves
Radio waves at lower frequencies can travel through walls whereas higher RF can travel in straight line and bounce back.The power of low frequency waves decreases sharply as they cover long distance. High frequency radio waves have more power. The range in frequencies of radio waves is from 20kHz 300Hz.
Applications
• television and FM and AM radio broadcasts
• military communications
- Radio Control Car
Microwaves
• Microwaves travel in straight lines, and so the transmitter and receiver stations should be accurately aligned to each other. Microwaves are unidirectional
• Microwaves electromagnetic waves having frequency in the range from 1GHz to 1000 GHz.
Applications
• Cellular phones
• 3G, 4G or 5G Network
• Satellites
• Wireless LAN
- Wireless PAN
Infrared
Infrared waves are those between the frequencies 300GHz and 400THz in the electromagnetic spectrum. Their wavelengths are shorter than microwaves but longer than visible light. Infrared propagation is line of sight. Range lies bwtween 300 GHz to 400 THz.
Applications
• Remote controls for television, stereos and other appliances.
• Wireless modem, keyboard, mouse, printer etc
• Night vision systems
• Motion detectors
- MRI
How Internet Works
IP Addressing IPv4 & IPv6
What is IP Address?
An Internet Protocol address is a numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication. An IP address serves two main functions: host or network interface identification and location addressing.
IP Addressing IPv4
• An IP address basically a 32-bit address that uniquely universally defines connection of host or a router to the Internet. IP address is unique.
• Introduced by IANA (Internet Assigned Numbers Authority).
• 32 bit is divided into 4 equal parts of 8–8 bits separated by dotted decimal notation. It is in the range of minimum 0.0.0.0 to 255.255.255.255.
• Each 8 bit group is known by OCTET.
Various IP classes
IP has five different classes differentiated by characteristics.
◦ Class-A ranges from 0 to 127
◦ Class-B ranges from 128 to 191
◦ Class-C ranges from 192 to 223
◦ Class-D ranges from 224 to 239
◦ Class-E ranges from 240 to 255
First Octet is defines the class of particular IP e.g. — 128.11.3.31 is follow in class –B
127.0.0.0 to 127.255.255.255 is a range of look back IP.
Class-A
Class A addresses only include IP starting from 1.x.x.x to 126.x.x.x only. The IP range 127.x.x.x is reserved for loopback IP addresses.
The default subnet mask for Class A IP address is 255.0.0.0 which implies that Class A addressing can have 126 networks (27–2) and 16777214 hosts (224–2).
Class B
Class B IP Addresses range from 128.0.x.x to 191.255.x.x. The default subnet mask for Class B is 255.255.x.x.
Class B has 16384 (214) Network addresses and 65534 (216–2) Host addresses.
Class C
Class C IP addresses range from 192.0.0.x to 223.255.255.x. The default subnet mask for Class C is 255.255.255.x. Class C gives 2097152 (221) Network addresses and 254 (28–2) Host addresses.
Class-D
Class D has IP address range from 224.0.0.0 to 239.255.255.255. Class D is reserved for Multicasting. In multicasting data is not destined for a particular host, that is why there is no need to extract host address from the IP address, and Class D does not have any subnet mask.
Class-E
This IP Class is reserved for experimental purposes only for R&D or Study. IP addresses in this class ranges from 240.0.0.0 to 255.255.255.254. Like Class D, this class too is not equipped with any subnet mask.
IP Addressing IPv6
• An IP address basically a 128-bit address that uniquely universally defines connection of host or a router to the Internet. IP address is unique.
• Introduced by IANA (Internet Assigned Numbers Authority).
• total of 4,294,967,296 unique IP addresses can be assigned to hosts.
• IP is like 2001:db8:1234::f350:2256:f3dd/64
• It supports Unicast. Telecast & Multicast.
- It doesn’t have Classes like ipv4
Subnet Mask, MAC, DHCP & DNS
What is Subnet Mask?
A subnet mask is a 32-bit number that segments an existing IP address in a TCP/IP network. It is used by the TCP/IP protocol to determine whether a host is on the local subnet or on a remote network. Subnet mask divides the IP address into a network address and host address, hence to identify which part of IP address is reserved for the network and which part is available for host use.
MAC Address
The Media Access Control (MAC) address is just as important as the IP address. The MAC address is a unique value associated with the network adapter (NIC). MAC addresses are known as the hardware addresses or physical addresses. They uniquely identify the adapter on the LAN.
MAC Address
DHCP
● Dynamic Host Configuration Protocol (DHCP)
○ From 1993
○ An extension of BOOTP, very similar to DHCP
○ Same port numbers as BOOTP
○ Extensions:
■ Supports temporary allocation (“leases”) of IP addresses
■ DHCP client can acquire all IP configuration parameters needed to operate
○ DHCP is the preferred mechanism for dynamic assignment of IP addresses
○ DHCP can interoperate with BOOTP clients.
APIPA
APIPA stands for Automatic Private IP Addressing (APIPA). It is a feature or characteristic in operating systems (eg. Windows) which enables computers to self-configure an IP address and subnet mask automatically when their DHCP(Dynamic Host Configuration Protocol) server isn’t reachable
DNS
DNS stands for Domain Name System. DNS is a service that translates the domain name into IP addresses. This allows the users of networks to utilize user-friendly names when looking for other hosts instead of remembering the IP addresses.
(The inverse domain is used for mapping an address to a name.)
(Generic Domains defines the registered hosts according to their generic behaviour.)
(The format of country domain is same as a generic domain)
Importance of DNS
WLAN & WPAN Networks
WLAN
A wireless LAN is a wireless computer network that links two or more devices using wireless communication to form a local area network within a limited area such as a home, school, computer laboratory, campus, or office building.
Wi-Fi
What is Wi-Fi
Short for “Wireless Fidelity”
A trademark of the Wi-Fi Alliance
The brand name for products using the IEEE 802.11 family of standards
Commonly used for “wireless local area network” (WLAN)
WPAN
A personal area network is a computer network for interconnecting electronic devices within an individual person’s workspace. A WPAN provides data transmission among devices such as computers, smartphones, tablets and personal digital assistants.
Bluetooth
Wireless Personal Area Networks (WPAN)
Design goal
Cable replacement
Low cost
Low power
Small size
For mobile devices
