Answer:- • ES5 • It is a fifth edition of the ECMAScript. • We can only define the variables only using the var keyword. • ES6 • It is a sixth edition of the ECMAScript. • We can define variables in two ways(let and const).

Answer:- o A network is a set of devices that are connected with a physical media link. In a network, two or more nodes are connected by a physical link or two or more networks are connected by one or more nodes. o A network is a collection of devices connected to each other to allow the sharing of data. o Example of a network is an internet. An internet connects the millions of people across the world.

Answer:- Network topology specifies the layout of a computer network. It shows how devices and cables are connected to each other. The types of topologies are: • Bus: • Bus topology is a network topology in which all the nodes are connected to a single cable known as a central cable or bus. • It acts as a shared communication medium, i.e., if any device wants to send the data to other devices, then it will send the data over the bus which in turn sends the data to all the attached devices. • Bus topology is useful for a small number of devices. As if the bus is damaged then the whole network fails. • Star: • Star topology is a network topology in which all the nodes are connected to a single device known as a central device. • Star topology requires more cable compared to other topologies. Therefore, it is more robust as a failure in one cable will only disconnect a specific computer connected to this cable. • If the central device is damaged, then the whole network fails. • Star topology is very easy to install, manage and troubleshoot. • Star topology is commonly used in office and home networks. • Ring • Ring topology is a network topology in which nodes are exactly connected to two or more nodes and thus, forming a single continuous path for the transmission. • It does not need any central server to control the connectivity among the nodes. • If the single node is damaged, then the whole network fails. • Ring topology is very rarely used as it is expensive, difficult to install and manage. • Examples of Ring topology are SONET network, SDH network, etc. • Mesh • Mesh topology is a network topology in which all the nodes are individually connected to other nodes. • It does not need any central switch or hub to control the connectivity among the nodes. • Mesh topology is categorized into two parts: o Fully connected mesh topology: In this topology, all the nodes are connected to each other. o Partially connected mesh topology: In this topology, all the nodes are not connected to each other. • It is a robust as a failure in one cable will only disconnect the specified computer connected to this cable. • Mesh topology is rarely used as installation and configuration are difficult when connectivity gets more. • Cabling cost is high as it requires bulk wiring. • Tree • Tree topology is a combination of star and bus topology. It is also known as the expanded star topology. • In tree topology, all the star networks are connected to a single bus. • Ethernet protocol is used in this topology. • In this, the whole network is divided into segments known as star networks which can be easily maintained. If one segment is damaged, but there is no effect on other segments. • Tree topology depends on the "main bus," and if it breaks, then the whole network gets damaged. • Hybrid • A hybrid topology is a combination of different topologies to form a resulting topology. • If star topology is connected with another star topology, then it remains star topology. If star topology is connected with different topology, then it becomes a Hybrid topology. • It provides flexibility as it can be implemented in a different network environment. • The weakness of a topology is ignored, and only strength will be taken into consideration.

Answer:- A list of advantages of distributed processing: • Secure • Support Encapsulation • Distributed database • Faster Problem solving • Security through redundancy • Collaborative Processing

Answer:- Network reliability: Network reliability means the ability of the network to carry out the desired operation through a network such as communication through a network. Network reliability plays a significant role in the network functionality. The network monitoring systems and devices are the essential requirements for making the network reliable.The network monitoring system identifies the problems that are occurred in the network while the network devices ensure that data should reach the appropriate destination. The reliability of a network can be measured by the following factors: • Downtime: The downtime is defined as the required time to recover. • Failure Frequency: It is the frequency when it fails to work the way it is intended. • Catastrophe: It indicates that the network has been attacked by some unexpected event such as fire, earthquake.

Answer:- There are mainly two security affecting factors: • Unauthorized Access • Viruses

Answer:- The following factors affect the reliability of a network: • Frequency of failure • Recovery time of a network after a failure

Answer:- The following factors affect the performance of a network: • Large number of users • Transmission medium types • Hardware • Software

Answer:- There are mainly two criteria which make a network effective and efficient: • Performance: : performance can be measured in many ways like transmit time and response time. • Reliability: reliability is measured by frequency of failure. • Robustness: robustness specifies the quality or condition of being strong and in good condition. • Security: It specifies how to protect data from unauthorized access and viruses.

Answer:- Every signal has a limit of upper range frequency and lower range frequency. The range of limit of network between its upper and lower frequency is called bandwidth.

Answer:- A network is a connection setup of two or more computers directly connected by some physical mediums like optical fiber or coaxial cable. This physical medium of connection is known as a link, and the computers that it is connected are known as nodes.

Answer:- A node that is connected to two or more networks is commonly known as a gateway. It is also known as a router. It is used to forward messages from one network to another. Both the gateway and router regulate the traffic in the network. • Differences between gateway and router: A router sends the data between two similar networks while gateway sends the data between two dissimilar networks.

Answer:- DNS is an acronym stands for Domain Name System. • DNS was introduced by Paul Mockapetris and Jon Postel in 1983. • It is a naming system for all the resources over the internet which includes physical nodes and applications. It is used to locate to resource easily over a network. • DNS is an internet which maps the domain names to their associated IP addresses. • Without DNS, users must know the IP address of the web page that you wanted to access. Working of DNS: If you want to visit the website of "javaTpoint", then the user will type "https://www.javatpoint.com" into the address bar of the web browser. Once the domain name is entered, then the domain name system will translate the domain name into the IP address which can be easily interpreted by the computer. Using the IP address, the computer can locate the web page requested by the user.

Answer:- • A forwarder is used with DNS server when it receives DNS queries that cannot be resolved quickly. So it forwards those requests to external DNS servers for resolution. • A DNS server which is configured as a forwarder will behave differently than the DNS server which is not configured as a forwarder. • Following are the ways that the DNS server behaves when it is configured as a forwarder: • When the DNS server receives the query, then it resolves the query by using a cache. • If the DNS server is not able to resolve the query, then it forwards the query to another DNS server. • If the forwarder is not available, then it will try to resolve the query by using root hint.