networkeducative

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Attenuation in Data Communication

Attenuation in Data Communication

Suppose two persons are talking over a wired connection. The sound, receiver hears is not loud enough to understand what the caller is saying. However, the caller is saying with enough loudness. So, what makes the volume go low at the receiver. The reason is attenuation, and it is caused due to the imperfection of the transmission medium.

In this case, wire is the transmission medium. Consider a voltage V is applied across a wire of resistance R, and current I flows through it for time t. Some of the electrical energy is lost to overcome the wire's resistance. The energy lost is dissipated as heat which is calculated as H = Rt*I^2 Similarly, when the signal travels through the transmission medium, it experiences some resistance. The signal loses some of its energy to overcome the resistance. This loss of energy of a signal is called attenuation. It decreases the amplitude of the signal obtained at the receiver, which reduces the volume of the sound the receiver hears. The signal's amplitude is increased with devices called amplifiers to compensate for the losses due to attenuation. It makes the sound at the receiver loud enough.

So, along with a wire or transmission medium, the signal loses its strength as it moves from point A to point B and gains strength from point B to point C. The loss or gain in signal's strength is measured in dB and calculated as 10log10(P2/P1), where P1 and P2 are the powers of the signal at two points. If the dB value is negative, then the signal is attenuated. If the dB value is positive, then the signal is amplified.

Let us take an example. A signal travels through the transmission medium, and its power is reduced to one-half, then one can calculate the dB value as dB = 10 log10 [(P1/2)/P1] = -3 dB It means the signal is attenuated by 3 dB.

We can also add the dB numbers. Therefore, one can calculate the dB value between two points by adding the dB values at several points. To understand this, let us take the transmission medium where the signal is first attenuated by 3 dB, then amplified by 7 dB. Finally, it is attenuated by 3 dB. One can find the resultant dB value for the signal between points A and D by adding the dB values between each set of intermediate points. It comes out to be 1 dB. It means the signal has gained power as it moves from point A to point D.

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What  is UDP Lite ?

Introduction

We use TCP and UDP all the time but are you familiar with the newer UDP light isn't UDP already lightweight how much lighter can it get stick around.

UDP Lite

And we'll see the first thing we need to look at is the checksum in UDP we're talking regular UDP at this point not UDP light UDP may have a checksum this means UDP can protect against payload corruption or it can ignore it entirely if there's no checksum a payload may be corrupted beyond use and UDP won't know if there is a checksum a single bad bit in the payload will cause validation to fail and the entire UDP datagram will be thrown away it won't be resent as UDP does not have any mechanism to resend missing data so UDP has an all or nothing approach to data loss UDP light is nearly the same as regular UDP it is still connectionless it still uses ports and so on but it has a different approach to the way it handles the checksum in fact it has a partial checksum the idea behind this is that the application that uses the data in the payload knows best and may be able to recover from small errors think of a voice codec for example it knows how to handle voice errors better than UDP does so to achieve this UDP light sees two parts of each payload one part is sensitive and the other part is insensitive the partial checksum covers the sensitive area this is the part of the payload that cannot withstand corruption if a single bit is wrong here the UDP datagram is discarded as normal if there's any errors in the insensitive part UDP lite just will not care and will deliver the datagram to the application as normal UDP lite is useful for multimedia applications like voice and streaming video to these applications a damaged packet is still better than no packet at all these applications will use advanced codecs which will be able to correct or conceal small errors it's easier to hide an error from a few bad bits than it is to hide an entire missing packet and that's all there is to UDP lite nearly the same as regular UDP just with some better handling for damage datagrams.

Conclusion

UDP Lite is a very efficient version of UDP. UDP may have a checksum. If it does use a checksum and a single bit is off, the checksum won’t match and the entire datagram will be discarded. UDP Lite takes a different approach. It uses a partial checksum. This means that the checksum covers only an area of the payload marked as ‘sensitive’. If a bit changes in the ‘insensitive’ area, the UDP segment is still delivered as normal. This is used with voice and video traffic, which will usually have advanced codecs to detect problems and conceal or repair them.

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Wi-Fi 6

Wi-Fi 6

Every day millions of Wi-Fi devices connect to the Internet in homes around the world. And each day millions more are added. Although each new Wi-Fi standard such as N and AC now known as Wi-Fi 4 and Wi-Fi 5 delivered greater and greater speeds, these Wi-Fi standards did not address the issue of increased Wi-Fi congestion and Wi-Fi capacity needed to handle the extreme number of devices being connected. Enter Wi-Fi 6 – The New Standard of Wi-Fi.

Explanation

Wi-Fi 6 is engineered to meet the growing demands on Wi-Fi by dramatically increasing performance and capacity Wi-Fi 6 delivers up to 4 times more capacity than older Wi-Fi standards at the foundation of Wi-Fi 6 are the number of available Wi-Fi streams. With each Wi-Fi stream more speed, range, and capacity are delivered. Now Wi-Fi 6 routers can deliver up to 12 simultaneous Wi-Fi streams. OFDMA is the key feature that significantly increases Wi-Fi efficiency. With OFDMA a Wi-Fi 6 router can deliver data to, and receive data from, multiple devices all at the same time. Wi-Fi 6 represents a new era of Wi-Fi. It also remains 100% backwards compatible with older Wi-Fi devices and can improve their wireless connections too. Simply powerful. Wi-Fi 6 gives you fluid performance, more range, and increased capacity. Experience faster Wi-Fi speeds from multiple devices all at the same time. Learn about the benefits of upgrading to the next generation of Wi-Fi and why it's time to spend less time buffering and more time doing.

What makes Wi-Fi 6 redefining?

Load faster. Stream smoother. Wi-Fi 6 comes equipped with up to 12 Wi-Fi streams and up to 4x the capacity of previous Wi-Fi standards. More power for more devices. Wi-Fi 6 gives you a 40% increase in data throughput and is fully backwards compatible with older Wi-Fi devices.

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Noise in Networking

Noise in Networking

Networking involves one sender and one receiver. The sender sends signals to the receiver via a transmission medium for example, wire. Unfortunately, the transmission mediums are not perfect, so the signal received is not what is sent. One of the reasons for the transmission impairment is noise.

In networking, noise is an unwanted signal produced in the transmission medium. It comes from the sources that carry electricity - for example, AC power cables, motors, and fluorescent lights. It affects the quality of the desired signal.

The noise can be:

Thermal Noise

Induced Noise

Crosstalk

Impulse Noise

Thermal Noise

The thermal noise is generated due to the random motion of electrons in a wire. Thermal noise is always present in the electrical equipment and is directly proportional to the temperature of the wires. It is also known as Johnson-Nyquist noise, Johnson noise, or Nyquist noise. Elimination of thermal noise is impossible; however, reducing the temperature or resistance in electrical circuits can reduce the thermal noise.

Induced Noise

Induced noise is the noise that produced in a circuit by a fluctuating magnetic or electrostatic field produced by another circuit. For example, AC power cables produce magnetic fields, and fluorescent light produces electrostatic fields. Once this electrostatic or magnetic energy gets in the equipment, the energy is converted to noise, called induced noise. The induced noise can be reduced by using twisted pair cables, proper grounding, and shielding the networking cables.

Crosstalk

In crosstalk, the signal in one wire affects the signal in the other wire. One wire act as sending antenna, and the other wire acts as receiving antenna. Crosstalk could cause you can hear someone else's discussion. Twisted-pair cable, shielded cable, and keeping cables further apart help avert crosstalk.

Impulse Noise

Impulse noise is a spike generated in the transmission medium from power lines or lightning. Impulse noise increases or decreases a circuit's signal level; this causes the receiving equipment to misinterpret the signal.

A noise-free medium is not possible in reality. So, the signal delivered to the receiver always has a noise component, and therefore, a significant noise power. The ratio of the average signal power to the average noise power is called signal-to-noise ratio or SNR. High SNR means the signal is less corrupted by noise, and low SNR means the signal is more corrupted by the noise. Therefore, a larger SNR makes it easier for the receiver to extract the transmitted signal from the background noise.

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30 Top Networking Interview Questions

30 Top Networking Interview Questions

1)What is the difference between a firewall and a router?

A firewall is a device that blocks unwanted or unauthorized traffic while allowing desired traffic to pass through it. A firewall blocks incoming and outgoing network traffic while a router allows traffic to pass from one network to another.

A router is a device that forwards IP packets. A router has an IP address that identifies the router. This IP address is used by hosts and other devices on the network to send IP packets to the router. The router then looks at the destination IP address and determines how to forward the packet to its destination.

2)What is a CACHE?

A cache is a memory that temporarily stores recently accessed data. This helps to reduce the number of times the data has to be retrieved from the hard drive or other memory device. A cache is like a shortcut in the hard drive that is used to reduce the time it takes to retrieve data.

3)What is a network?

A network is a collection of computers and other devices connected together that share information and resources. A network is a network of networks. A computer connected to a network is called a host. A computer on the same network as another host is called a peer.

4)What is a port?

A port is a logical communication channel through which two hosts can communicate. A port can be on a host, a router, or a switch. The most common type of port is a network port. A network port is used to connect to a network. Network ports can be used for sending and receiving data, or for connecting to other devices such as routers.

5)What is private IP Address?

A private IP address is an IP address that is only used on a single network. Private IP addresses are often used by home and small business users to connect their computers to the Internet.

6)What is a Virtual Private Network (VPN)?

A VPN is a private network that is used to provide a secure connection between two or more private networks. VPNs can be used to provide a secure connection between two or more private networks.

7)What are the advantages of a firewall?

A firewall is a device that blocks unwanted or unauthorized traffic while allowing desired traffic to pass through it.

A firewall is used to prevent hackers and unauthorized users from accessing network.

8)What is a DNS?

A DNS is a directory service that maps IP addresses to domain names. A DNS is a database that is used to map IP addresses to domain names. DNS is used to provide the internet with a way to find a domain name for an IP address.

9)What is Windows Firewall?

A Windows firewall is a built-in firewall that is included in Windows operating systems. Windows firewalls are enabled by default and can be configured to prevent network access for most applications.

10)What is a proxy?

A proxy can be used to provide an additional layer of security. A proxy can be used to encrypt data or to prevent users from viewing or modifying the data.

11)What is port blocker?

A port blocker is often used to prevent someone from connecting to a port that is being used for an illegal purpose.  A port blocker can be used to protect a computer or network from viruses or hackers.

12)What is an ISP?

An Internet Service Provider (ISP) is a company that provides access to the Internet. An ISP can be an organization that owns the Internet infrastructure or a company that provides access to the Internet.

13)What is a digital wall?

Digital walls are often used by large companies that need to control access to their computer networks.

14)What are the different types of routers?

Routers can be of three types. A managed router, a network router, and a router in a box.

A managed router is a router that is managed by an organization. A managed router is often used by companies that need to control access to their computer networks. Managed routers are often referred to as firewalls.

A network router is a router that forwards data between two or more networks. Network routers can be used by a company to connect their network to another network.

A router in a box is a router that is sold as a standalone device. A router in a box is often used by small businesses.

15)What Is a VLAN?

A VLAN is a type of private network that is used to provide a secure network for a specific group of computers. A VLAN can be used to provide a secure network for a group of computers that share a common set of resources. Basically, VLANs are the division of the single broadcast domain into the multiple broadcast domain to provide a secure network group.

16)WHAT IS A DHCP?

A DHCP is a protocol that provides IP addresses dynamically to hosts on a network.

17)What Is an IP Address?

An IP address is an address that is used to identify computers on a network. Basically, IP is the identification of the specific device on the network. And that address is the 32-bit address.

18)What are the Benefits Static Routing?

It is the secure routing.

It is fast routing.

And the Administrative value is 1.

Effective for the small organizations.

19)Why we use default routing?

Generally used for the unknown destinations and mostly used in the internet and this routing is mostly used to reduce the size of the routing table but that routing is last preferred routing.

20)What is hello and hold down timer of the OSPF?

Hello Timer is 10 seconds.

Hold Down Timer is 40 seconds.

21)What is the Multicast Address of the RIPng?

The Multicast Address of the RIPng is the FF02::9.

22)What are the flaws in the Routing information protocol?

Don’t support the classless addressing.

Updates are Broadcast.

Maximum Routers in the RIP are 16.

Exchange entire routing table after every 30 seconds.

23)Why areas introduced in the Open Shortest Path First Algorithm?

Areas introduced just for the traffic management.

24)What is the range of the private Autonomous System?

The private range of the AS is 64512-65535.

25)What is the BGP TCP port number?

BGP TCP port number is 179.

26)What are the metrics of the ISIS protocol?

Delay

Expense

Error

27)What are the ISIS PDUs?

Hello PDU.

Link State PDU.

Complete Sequence Number PDU.

Partial Sequence Number PDU.

28)What are the States of OSPF?

There are the following 7 states of the OSPF:

Down State

Init State

Two-way State

Exstart State

Exchange State

Loading State

Full State

29)Which OSPF LSA type is for externals LSA?

OSPF LSA type-5 is the type that is for the externals LSA.

30)How many hops count support the OSPF and EIGRP?

OSPF support the unlimited hops count.

EIGRP support the 255 hops count.

[networkeducative]

File Transfer Protocol

File Transfer Protocol

The File Transfer Protocol, or FTP is used to transfer computer files between two different locations over the Internet with the purpose of distribution. This protocol was developed by software developer Tim Berners-Lee in order to distribute computer files with the World Wide Web back in 1980 with the name CERN FTP. To accelerate this process, it ran on computers with Unix-based interfaces. For that reason, most people actually use FTP whenever they upload or download any type of data via web browsers on their computers. It is by far one of the oldest file transfer protocols conceived long before HTTP and HTTPS were invented, which created an atmosphere where it is no longer safe for transferring sensitive information over the internet. Nevertheless, it is still used for data transfer because earlier versions are not per se secure but they are fast. FTP is a protocol that was originally developed to transfer files between two different computers over the internet. The reason for its development was to speed up the process of downloading and uploading files. The file transfer protocol can be used to transfer files between a computer and a remote server, or between two different remote servers.

FTP is very simple to use and anyone can do it. You need to know how to navigate the FTP folder on your computer, and that's it. This protocol can be used with all types of file systems. It is, in fact, the oldest protocol used in this context. It is a text based protocol that is easy to understand and implement. FTP is also used for the transfer of data between two different computers and is implemented in every operating system. The File Transfer Protocol is often used to transfer files between two computers, but there are many different versions of it, one of which is the Secure FTP (SFTP). SFTP is the newer version of FTP and it is implemented in most operating systems, such as Microsoft Windows and Linux. In addition, SFTP uses the Secure Shell (SSH) protocol, which is more secure and robust.

FTP Port Number

21

Is FTP Secure ?

FTP is a very old protocol that is considered safe to use. However, it has a weakness, which is the fact that it is text based and you have to have a computer with a UNIX-based operating system to use it. Because of this, the protocol is not considered secure. If you want to know if the FTP is secure, you can use the following two steps. First, you have to verify that the protocol you use to connect to the FTP server is secure. Second, you have to verify that the FTP server you are using has the latest version of the FTP software installed. If both these conditions are met, you can use the FTP server to transfer your data without any problems.

How FTP works ?

The file transfer protocol is based on the concept of connecting to a remote server and downloading or uploading files to the server. When you are connected to the server, you can access the data you want. It is like a file storage space that is linked to a computer that has a file transfer protocol software installed on it. The software can be run on a local computer or on a remote server.

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Load Balancing in Networking

Load Balancing in Networking

A load balancing is a form of computer network traffic management for ensuring server performance and uptime by distributing tasks over multiple computers, known as servers, in such a way as to minimize the impact of any single machine's downtime. Load balancing can also be considered an approach to deal with overloading of one particular service or process. Load balancing commonly uses one of four methods- least connections, client request rate, server response time, or round robin. However, these methods are not mutually exclusive- they can be used together to take different measurements at different times to find the method best suited for the situation. Load balancing also refers to the workload distribution between different systems that provides location redundancy or geographical diversity.

What is Load Balancing?

Load Balancing is a technique used to improve the performance of a network service. It is used to distribute incoming network traffic over multiple servers, in such a way that it is possible to continue serving requests even if one server fails. Load balancing is a form of computer network traffic management for ensuring server performance and uptime by distributing tasks over multiple computers, known as servers, in such a way as to minimize the impact of any single machine's downtime. Load balancing can also be considered an approach to deal with overloading of one particular service or process.

High Availability

Load Balancing can be considered a form of High Availability (HA). HA refers to the ability of a network to maintain availability and provide a level of service even if one of the components fails. In a High Availability (HA) environment, it is essential that when a component fails, it is automatically replaced with another component in order to maintain service. Load Balancing can be considered a way of achieving this. Load Balancing with respect to HA refers to the ability of a network to maintain availability and provide a level of service even if one of the components fails. Load Balancing can be considered a way of achieving this.

What are some of the benefits of load balancing?

Load balancing improves network reliability by distributing incoming network traffic to several servers or application components. Load balancing helps in preventing a single server or application component from becoming overloaded. It also improves the overall performance of the server or application component. Load balancing improves the overall performance of the server or application component by distributing the incoming traffic to several servers or application components. Load balancing improves network reliability by distributing incoming network traffic to several servers or application components. Load balancing helps in preventing a single server or application component from becoming overloaded. It also improves the overall performance of the server or application component.

What are some of the drawbacks of load balancing?

Load balancing can slow down the performance of a server or application component if the load is distributed to it for too long. Load balancing can slow down the performance of a server or application component if the load is distributed to it for too long. HTTP traffic is the most common type of traffic received by a Load Balancer and so that is the drawback for the http traffic.

What is the difference between load balancing and proxy caching?

Load balancing is a network function that is responsible for distributing the incoming traffic to one or more servers or application components in the network. Proxy caching is a process of caching the content of a web page in the client's web browser. The client caches the content of a web page in the client's web browser.

Load Balancer Perf Tuning

Load Balancer Perf Tuning is the process of optimizing the performance of a Load Balancer and its associated components. The Load Balancer is one of the most important components in the whole system. It is the component that acts as the dispatcher of all incoming traffic. If the Load Balancer is not performing well, it can impact the performance of the entire network. There are various factors that can affect the performance of the Load Balancer and they need to be optimized to ensure maximum performance. The following sections cover the factors that affect the performance of the Load Balancer and the steps to be taken to improve its performance. When Load Balancer is overloaded, it can slow down the performance of other components in the network.

What Is the Goal of a Load Balancer?

There are two types of Load Balancer, i.e. the Ingress Load Balancer and the Egress Load Balancer. The Ingress Load Balancer receives the incoming traffic from the network and distributes it to the various servers or application components in the network. The Egress Load Balancer distributes the incoming traffic from the network to the various servers or application components in the network. The goal of the Ingress Load Balancer is to distribute the incoming traffic to the various servers or application components in the network evenly. The goal of the Egress Load Balancer is to distribute the incoming traffic from the network to the various servers or application components in the network evenly.

How Do Load Balancers Work ?

A Load Balancer is a piece of network equipment that forwards incoming network traffic from one network port to another network port. The Load Balancer is configured to receive incoming network traffic and forward it to one or more servers or application components in the network. The Load Balancer maintains a record of the connection and the amount of data transferred during the connection. The Load Balancer forwards the incoming traffic from the network to the servers or application components based on this record. If the incoming traffic to a server or application component is low, the Load Balancer sends the traffic to that server or application component.

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SMTP | Simple Mail Transfer Protocol

SMTP | Simple Mail Transfer Protocol

SMTP is simple mail transfer protocol. It means that if your email server supports SMTP then it's easy to use for sending emails over the internet. It's important because without SMTP the internet would not look anything like what it does today.

What is Simple Mail Transfer Protocol (SMTP)?

SMTP is an email protocol that is used by email servers to transfer email messages. It's very important for an email server to support SMTP. If your server doesn't support SMTP, you can use any other method to send email. But this would not be the same as sending email from an email server. SMTP is the protocol that is a for sending email messages. The format of an email message is described by the MIME standard, which specifies the structure of a message in a way that is independent of the transport mechanism. In other words, you can send an email from a website or a computer program without using SMTP.

What is the goal of SMTP?

SMTP is used to send email messages. There are many different ways to send an email message. It is possible to send an email message using an email client or a web browser. The way that SMTP is used to send an email message is called SMTP-to-email conversion. Simple mail transfer protocol is used to send email messages between mail servers. The mail servers are computers or web servers that receive email messages and forward them to other servers. The SMTP-to-email conversion is not the only way to send email between mail servers. Another way is called IMAP-to-email conversion. SMTP-to-email conversion.

How to get started with SMTP?

Following are the two ways to get started with SMTP:

There are email servers that support SMTP.

There are email clients that support SMTP.

If your email server supports SMTP, you can use the SMTP server directly to send email messages. If your email client supports SMTP, you can use the SMTP server directly to send email messages.

How to send an email message using SMTP?

You can send an email message using SMTP using the commands described in the RFCs. There are two types of SMTP commands:

SMTP commands for sending email messages

SMTP commands for receiving email messages

SMTP Protocol Verification

To verify that your SMTP server supports SMTP, you can send an email message using the telnet program. That connects to the email server and sends an email message. If you get a reply message from the server, the server supports SMTP. If you get a reply message from the server with a syntax error, the server does not support SMTP.

Why use SMTP?

SMTP is the only way to send email messages. Simple Mail Transfer Protocol is the standard for sending email messages. There are many ways to send an email message.

You can use an email client, like as Outlook Express.

You can use a web browser, like as Internet Explorer.

How does SMTP work?

SMTP consists of the following four parts:

A SMTP-to-email conversion is performed by the SMTP server.

A SMTP client (usually a web browser) sends a mail message.

A mail server delivers the mail message to the recipient.

A recipient (such as a mail server) sends an email message back to the sender.

SMTP used to send email messages. A SMTP client can send email messages using SMTP commands. The SMTP commands are defined in the SMTP RFC, RFC-821. A typical SMTP client is a web browser. The web browser connects to the SMTP server and sends a mail.

Conclusion

SMTP is a way to send email messages. There are many ways to send an email message. It is possible to send an email message using an email client or a web browser. The way that SMTP is used to send an email message is called SMTP-to-email conversion. Simple Mail Transfer Protocol (SMTP) is a protocol that is for sending the email messages. It is a generic protocol, meaning it can be used to send email from any mail server.

There are two types of SMTP commands:

SMTP commands for sending email messages

SMTP commands for receiving email messages

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Hot Standby Router Protocol

HSRP

HSRP is common Layer 3 hardware-based redundancy protocol used in campus networks with multiple VRFs. In a nutshell, it uses two routing devices as active and standby VIPs, respectively. When the active router fails, the standby router becomes active without any reconfiguration of IP address information.

What is HSRP?

HSRP is an automatic failover system that is used to balance the traffic across multiple routers and allows the network to automatically switch the data traffic to the standby router without the need for any manual configuration changes. HSRP is usually used to keep the connectivity between two devices even if the router fails.

Router Failover

What is Router Failover? Router failover is the process of switching the traffic from one router to another router when the current router fails. This may be done manually or automatically. In the case of manual failover, the administrator will manually change the IP address information of the failed router. The automatic failover is done by using the HSRP protocol.

What is the Failover Time?

The failover time refers to the time from the moment when the active router fails until the moment when the standby router becomes active. The failover time depends on the type of router and its protocol. For example, with the HSRP protocol, the failover time is the time required for a switch to change the active router to the standby router. The time is measured in seconds.

How to set up HSRP?

To set up HSRP, you will need to set up the two routers as active and standby routers. The routers must be able to talk to each other. To do this, you will need to enable multicast on the routers. You can enable the multicast on both the routers.

How HSRP Works ?

When a router receives a packet with an IP address, it checks the local routing table to determine which interface to forward the packet. HSRP operates in the same way as IP routing, but it works with the VRF (Virtual Routing and Forwarding) instead of the IP routing. The difference is that HSRP only works with a particular VRF, which is selected by default. An IP address that belongs to a specific VRF is called a virtual address.

What are the advantages?

There are a number of advantages to using HSRP:

In a nutshell, it uses two routers as active and standby VIPs, respectively.

If the active router fails, the standby router becomes active without any reconfiguration of IP address information.

It is common to use multiple VRFs in a campus network, and HSRP is a common Layer 3, hardware-based redundancy protocol used in campus networks with multiple VRFs.

What are the disadvantages?

As mentioned, the HSRP protocol has a security problem. To solve this problem, it is possible to prevent this attack. For example, when an attacker finds the IP address of the standby router, he can change it to the IP address of the active router. If the active router fails, the standby router becomes active without any reconfiguration of IP address information.

HSRP Vulnerability

As mentioned, the HSRP protocol has a security problem. To solve this problem, it is possible to prevent this attack. For example, when an attacker finds the IP address of the standby router, he can change it to the IP address of the active router. If the active router fails, the standby router becomes active without any reconfiguration of IP address information.

HSRP Vulnerability Solution

To sum up, it is possible to prevent the attack of a passive intruder by using the HSRP protocol. The attack is also prevented by setting the failover time to a relatively short period of time.

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Wireshark - The Ultimate Network Protocol Analyzer

Sniffer

Sniffers are programs that capture and analyze network data. A sniffer can be used to capture data that is not in a format that can be analyzed by a protocol analyzer. For example, a sniffer can capture and analyze data from different protocols like TCP, UDP, ICMP, DHCP, HTTP, HTTPS, DNS, NTP, SNMP, FTP, etc. A sniffer can also be used to capture data that is not in a format that can be analyzed by a protocol analyzer.

Wireshark

By using Wireshark, you can capture and analyze the data from a network. You can capture and analyze data from different protocols like TCP, UDP, ICMP, DHCP, HTTP, HTTPS, DNS, NTP, SNMP, FTP, etc.

Introduction

Wireshark is a network protocol analyzer. You can capture and analyze data from different protocols like TCP, UDP, ICMP, DHCP, HTTP, HTTPS, DNS, NTP, SNMP, FTP, etc. You can also see and analyze the network activity of different devices on the network.

The Basics

Wireshark can be used to sniff the network. You can use Wireshark to capture and analyze data from different protocols like TCP, UDP, ICMP, DHCP, HTTP, HTTPS, DNS, NTP, SNMP, FTP, etc. You can also view the data in the ASCII format. You can also search for the packets based on different criteria like packet content, destination IP, etc. You can view the network activity of different devices on the network.

What is the scope of Wireshark?

Wireshark can capture and analyze data from different protocols like TCP, UDP, ICMP, DHCP, HTTP, HTTPS, DNS, NTP, SNMP, FTP, etc. Wireshark can capture and analyze data from different protocols like TCP, UDP, ICMP, DHCP, HTTP, HTTPS, DNS, NTP, SNMP, FTP, etc.

What Does Wireshark Do?

Wireshark is an open-source packet analyzer. It has the following capabilities:

Capture, filter and replay packets.

Display packet headers and raw data.

View raw packet data in the ASCII format.

Search for packets based on different criteria like packet content, destination IP, etc.

Automatically disassemble and decompress protocols like TCP, UDP, ICMP, HTTP, HTTPS, etc.

Graph the data.

Compare and analyze the data from different protocols.

Create and view the traffic in the Graphical Protocol Analyzer (GPA).

Wireshark is a packet sniffer.

Wireshark Setup

There are different methods to set up Wireshark in system. You can download the latest version of Wireshark from the Wireshark website.

Open the downloaded archive and unzip the package.

Open the terminal and change the working directory to the location where you have unzipped the package.

Now, you  install Wireshark.

How do I use Wireshark?

You can use Wireshark by either starting it from the command line or using the graphical user interface (GUI). Wireshark has both GUI and command line interfaces.

Using the GUI

You can start Wireshark from the command line by typing the following: $./wireshark

You can also start Wireshark from the graphical user interface.

To start Wireshark from the graphical user interface:

Go to Start > Programs > Wireshark > Wireshark

Select the first option (Run as Administrator)

Enter the password if required

Click OK

The Wireshark GUI will start.

How does Wireshark work?

Wireshark works by capturing and analyzing the data that flows across a network. Wireshark can capture and analyze data from different protocols like TCP, UDP, ICMP, DHCP, HTTP, HTTPS, DNS, NTP, SNMP, FTP, etc. You can see and analyze the network activity of different devices on the network.

Wireshark also supports analyzing and displaying a wide variety of information such as:

Packet capture data

TCP/IP protocol stack information

TCP, UDP, ICMP, ARP, DHCP, HTTP, HTTPS, DNS, NTP, SNMP, FTP, etc. protocols

Captured data

Traffic information

Host information

Domain

What is the target audience?

You should use Wireshark if you plan on:

Analyzing network data

Analyzing traffic flows on any network such as LAN, WAN, Internet or Intranet

Analyzing packets for security and intrusion

What is the default Wireshark Port?

If you are capturing Wireshark traffic on your system, make sure you don’t have another program running on the same Wireshark port. You can use Wireshark by logging in using a remote host. If you are logging in using the Linux or Mac command line, the default Wireshark port is 53, for Windows users, the default Wireshark port is 1024.

Other Wireshark Resources

https://www.wireshark.org/

[networkeducative]

GNS3

GNS3

Tool GNS3, a graphical network simulation software, is a cross-platform package including a GUI, a command line-based Simulation program, and a Virtual Machine. GNS3 is an open source software for building networks in a modeler environment. You can create models of computer networks and then you can use GNS3 to validate or test the behavior of such models. A simulation model typically consists of nodes and links between these nodes. Nodes represent devices such as server computers, workstations, switches/hubs, etc., while the links represent the connections between these nodes which typically configured including bandwidth and delays. You can use emulation features to change parameters such as packet loss and link load and/or you can define the type of traffic coming from one node to another node. GNS3 is a free and open-source simulator. You can run simulations in either simulation mode, which provides an integrated GUI for a network simulator, or command-line mode. It has support for IPv4, IPv6, and OSI Layer 2, Layer 3, and OSI Layer 4 protocols. GNS3 can simulate protocols such as TCP/IP, UDP/IP, IPX, and AppleTalk. GNS3 is released under the GNU GPL.

GNS3 Features

Simulation mode: GNS3 has an integrated graphical interface for network simulation, and command-line interface.

IPv4, IPv6, and OSI Layer 2, Layer 3, and OSI Layer 4 protocols.

Command-line mode: You can use GNS3 command-line interface for more power.

You can use emulation features to change parameters such as packet loss and link load.

You can define the type of traffic coming from one node to another node.

It supports the L3 protocols like TCP, UDP, ICMP, IGMP, and PIM.

GNS3 can simulate protocols such as TCP/IP, UDP/IP, IPX, and AppleTalk.

Why Should I Use GNS3?

GNS3 is useful for simulating any type of network using emulated or real devices.

Ability to simulate various types of networks such as point-to-point, point-to-multipoint, broadcast, VLANs, Layer 2 switches, Layer 3 switches, and routers.

Ability to test your network and how it will behave when the load is changed.

Packet and IP level traffic generation

GNS3 has a real-time traffic flow simulator.

Network and performance analyzers.

Dynamic routing, protocols, and multicast.

Port forwarding, NAT, and firewall.

What Are the Different GNS 3 Versions?

GNS3 has several versions. You can download the latest version from https://www.gns3.com. The GNS3 Simulator is a free software for testing and learning. GNS3 uses a graphical user interface (GUI) that you can use to build and test networks. The GNS3 Simulation program is used to perform a simulation of a network, and the Virtual Machine is used to run the simulation.

How Do I Install GNS3?

GNS3 has two ways to install:

You can download the latest version from https://www.gns3.com and install the latest version from the download.

You can install the simulator and virtual machine

What are the GNS3 Packages?

GNS3 Packages are the GNS3 software which contains all the necessary tools to simulate networks. GNS3 Packages are available in RPM and DEB format.

How Do I Use GNS3?

Install the GNS3 Packages on your operating system.

You can download the latest version from https://www.gns3.com and install the latest version from the download.

You can install the simulator and virtual machine.

Download the GNS3 Simulator.

GNS3 Simulator is the graphical user interface (GUI) for the GNS3 Simulation program. You can use the GNS3 Simulator to build and test your networks.

How Do I Install the GNS3 Python Module?

Download the latest version from https://www.gns3.com and install the latest version from the download.

Extract the archive and you will see the GNS3 Python module in the directory.

Install the module.

How Do I Install the GNS3 QEMU Virtual Machine?

Download the latest version from https://www.gns3.com and install the latest version from the download.

Extract the archive and you will see the GNS3 Virtual Machine in the directory.

Install the virtual machine.

What Is the GNS3 API?

GNS3 API is the interface to GNS3 program.

[networkeducative]

Simple Network Management Protocol

Simple Network Management Protocol

The Simple Network Management Protocol (SNMP) is an approach for managing network-attached devices. The SNMP, which was initially created in 1988, is designed to monitor the status of network components and network items that include software, hardware, link utilization, interface temperatures, processors, memory utilization and more. SNMP operates on all equipment used for private internet access like routers, switches and servers. As a protocol, SNMP almost exclusively operates over the Internet Protocol (IP), typically using port 161 or 161U where 161 is the standard port used by SAP for version 1 of the protocol and 161U is the standard port used by SAP for v2 of the protocol.

What is SNMP?

The SNMP is an open standard that defines how network management applications, such as Hewlett Packard's Network Node Manager (NNM) or Cisco's Integrated NetFlow Monitor (INM), can be integrated into network devices to monitor and control the devices' performance. The SNMP is not a network operating system, nor is it a management application. It is a set of standards for management applications that provide information about the network device. The SNMP uses a management information base (MIB) to store information about the device. This information is shared with management applications. The MIBs that describe a device are contained in an object. A management application can obtain information about a device by accessing the object that describes the device.

MIB

The MIB defines the information that is stored about the device and its operation. The MIB is a database that contains definitions for objects that describe the device and its operation. The MIB defines the SNMP operations that can be performed on the device.

SNMPv1

SNMPv1 is defined in RFC 1157. The SNMPv1 protocol has three different modes of operation:

A Management Information Base (MIB)

A Management Information Tree (MIT)

A Simple Network Management Protocol (SNMP) Agent

SNMPv2

SNMPv2 is defined in RFCs 1912 and 2161.SNMPv2 supports the following three MIBs:

The Management Information Base (MIB)

The Management Information Tree (MIT)

The Simple Network Management Protocol (SNMP) Agent

SNMPv3

The SNMPv3 protocol is designed to provide new capabilities to the SNMP protocol. The new capabilities include:

Improved scalability

Improved security

Improved management of large networks

Improved MIBs

Improved management of large networks

Increased scalability

SNMP Objectives

The SNMP is a protocol for network management. The SNMP has multiple objectives:

To support network management applications that access and control network devices.

To support the transfer of management information about the device.

To define a set of objects that describe the device.

Provide a mechanism for management applications to access and control devices.

Provide a mechanism for management applications to transfer management information about the device.

SNMP Authentication

SNMP authentication is the process of proving that a message was sent by a user with the right authorization. SNMP authentication is performed when the management application receives a message.

Common SNMP Errors

Errors that occur when SNMP operations are performed. The following common errors that can occur when SNMP operations are performed.

Invalid OID: An OID is not valid.

Invalid MIB: An MIB is not valid.

No MIB No: MIB exists.

Unsupported OID: An OID is not supported.

Unsupported MIB: An MIB is not supported.

SNMP Traps

The SNMP Trap is a mechanism that allows a management application to notify another management application that a particular event has occurred. The management application can notify the other management application by sending a trap message. A trap is sent by a management application when a specific event occurs. The management application must specify the SNMP version and the type of trap. The management application must specify the OID that identifies the event that occurred. The OID is an OID that identifies a particular event. There are three types of traps that can be sent by the management application:

An SNMPv1 Trap

An SNMPv2 Trap

An SNMPv3 Trap

[networkeducative]

Prerequisite knowledge to Pass CCIE Routing and Switching

Prerequisite knowledge to Pass CCIE Routing and Switching

Introduction

General Guidelines

Course Introduction

Course Scope

Basic Networking Terms

TCP/IP & OSI Model

Introduction to Network Devices

Introduction to Decimal, Binary and Hexa-Decimal Numbers

Work experience on Recommended Software:

Putty/Secure CRT

Cisco Packet Tracer

GNS3

Web-IOU

EVE-ng

Addressing Schemes

IPv4 Addressing:

History of IPv4 Addressing

Format of IPv4 Addressing

Classification of IPv4 Addressing

Calculating Number of networks in classes

Calculation number of hosts per network

Concept of Network-id and Broadcast-id

Subnet Mask and Wildcard Mask

Concept of Default Gateway

Routed & Non-Routed Ports

Rules of IP addressing for Routed Ports

Classless IP addressing:

Subnetting and Super-netting

IPv6 Addressing:

History of IPv6 Addressing

Format of IPv6 addressing

Network Prefix and Interface ID

Types of IPv6 Addresses

MAC Addressing:

History of MAC addressing

Format of MAC addresses

Types of MAC addresses

Lab Setup Experience

Basic Lab Setup with Cisco Devices.

LAN and WAN cables

Physical Overview of Routers and Switches.

How to access network devices locally.

Difference between local and remote access.

Introduction to terminal applications such as Putty, Hyper terminal and Secure CRT etc.

Introduction to Cisco IOS and CLI.

Initial Configuration of Cisco IOS.

Introduction of different modes of Cisco IOS.

Configure and verify clock

Configure and verify hostname

Configure and verify user access verification or

login password

Configure and verify enable password

Configure and verify enable secret

Learn how to modify, copy, write and erase configuration.

Verify running-config and startup-config

Create username, password and their privileges

Configure banners:

motd

login

exec

Practice above configuration of Cisco Packet Tracer and GNS3.

Advanced Configuration

Introduction to LAN and WAN interfaces.

How to configure and troubleshoot Ethernet and Serial interfaces.

Configure description on interfaces.

Configure ipv4 and ipv6 addresses on interfaces.

Configure Keepalive, clock rate and encapsulation on interfaces.

How to make admin up and down interfaces.

Verify connectivity with test traffic.

Introduce ICMP-echo and echo-reply.

Use of ping command and understand output.

Impact of round-trip time.

Remote-access with TELNET and SSH.

Introduction of DNS.

Configure DNS.

Introduction to DHCP.

How to configure DHCP on Cisco IOS.

Basic Routing

Introduction to Routing for reachability.

Understand next hop.

How to configure next hop with:

Outgoing interface

Next Hop IP address

Understand static routing.

Configure and verify static routing for IPv4

Introduction to Dynamic Routing

Types of routing protocols

Interior gateway protocols:

RIP: Routing Information Protocol

OSPF: Open Shortest Path First

IS-IS: Intermediate System to Intermediate System

Exterior Gateway protocols:

BGP: Border Gateway Protocol

Administrative Distance or preference of routing methods.

Configure and verify Default Routing.

Configure and verify DHCP Relay Agent.

Network Services and IOS Features

IOS and Configuration Backup with TFTP

Configure and verify CDP

Configure and verify LLDP

Configure and verify NTP: Network Time Protocol

Password Recovery

Configure and verify Embedded Event Manager: EEM

Configure KRON Scheduler

Configure and verify SYSLOG

IPv6 DHCP Server, Client and Relay Agent

IP Traffic Management

Introduction to Access Control List

Configure and verify standard ACL

Configure and verify extended ACL

Contiguous and dis-contiguous wildcard mask

Implement named and numbered ACL

Introduction to public and private IP addresses

Introduction to NAT and PAT.

Configure and verify network address translation

Configure and verify PAT/NAT-overloading

Deep Dive into Dynamic Routing

Understand and Implement Routing Information Protocol.

OSPF: Open Shortest Path First

Link State Algorithm

OSPF Process-id.

OSPF Router-id.

Configure Loopback Interfaces

OSPF Area-id.

OSPF contiguous wildcard mask

OSPF Metric: cost

OSPF Tables:

Configure and verify single area OSPF.

Design and implement multiple area OSPF.

Regular and transit area.

Define Internal Router, Backbone Router,

Backbone Internal Router, Area Border Router

and ASBR.

Introduce and configure redistribution.

Define seed/external metric.

Type 1 and Type 2 seed metric.

Static routes with null-0 for testing.

OSPF and Policy Based Routing

Introduction to PBR tools:

Route-map

IP prefix-list

Distribute-list

ACL

OSPF Design constraints and filtering

OSPF Packet types

OSPF neighbor states

OSPF over multi-access networks

DR, BDR and DRO roles in multi-access networks.

Introducing OSPF LSA types 1 to 7.

Regular area types:

Stub Area

Totally Stubby area

NSSA: Not So Stubby Area

Totally NSSA

Configure and verify OSPF Virtual Links.

Continuous and discontinuous OSPF backbones.

OSPF filters:

IP prefix-lists

Area filters

Passive interface

Route summarization

Authentication

Troubleshooting

Understand network troubleshooting tools and

techniques

Ping      

Syslog:

Debugging

Conditional debugging

Traceroute

telnet  

Advanced show commands with filters

Troubleshoot RIP related issues.

Troubleshoot OSPF related issues.

Deep Dive into Exterior Gateway Protocol

Introduction to EGP

Historical Background

Introduction to Multihoming

BGP fundamentals.

Internal and External BGP.

BGP attributes: Weight, Local preference, As-path, Multi exit discriminator, Origin  

Router-id

BGP route-summarization

PBR with BGP attributes and PBR tools

Full Mesh i-BGP

Route-reflector configuration

BGP configuration best practices

BGP Packet types and states

BGP authentication

Deep Dive into Intermediate System to Intermediate System.

Understanding IS-IS routing protocol.

Importance of IS-IS in ISPs.

Comparison of OSPF and IS-IS

IS-IS L1, L2 and L1L2 Router roles

IS-IS L1, L2 and L1L2 neighbor relation.

IS-IS PDUs: L1 Hello PDU, L2 Hello PDU

L1 & L2 PSNP

L1 & L2 CSNP

IS-IS over multi-access network

DIS role in multi-access network

Route Leaking from L2 into L1

IS-IS for AF IPv6

Configure and verify Static Routing for IPv6 addresses.

Configure and verify RIP-ng

Configure and verify OSPF-v3

Configure and verify BGP (AF-IPv6)

Implementing VPNs DMVPN    

Introduction to Virtual Private Networks

Configure and verify GRE tunnels

Configure and verify IP-Sec :IKE 1, IKE 2

Configure and verify DMVPN: Phase 1, Phase 2, Phase 3

MPLS & MPLS VPN

Understanding Switching Architectures:

Control Plane

Data Plane

Understanding Routing Information Base

Understanding Forwarding Information Base

Understanding MPLS

MPLS header

MPLS Labels

Label Information Base

Label Forwarding Information Base

Label Allocation

Label Distribution

Label Retention

Configure and verify basic MPLS

Understanding MPLS VPN

VRF

Route Distinguisher

Route Targets

MP-BGP

Multicasting & QoS

Introduction to Multicasting

Multicast Source & Client

Multicast Routing

Protocol Independent Multicast

PIM Dense Mode

PIM Sparse Mode

Rendezvous Point: RP

Multicast Domain

BSR

IGMP

MSDP

Introduction to Quality of Service

Network Congestion Management

Classification and Marking

IP Precedence

DSCP

Congestion avoidance with WRED

Queueing Techniques

Policing and Shaping

Ethernet Switching

Forwarding on the basis of MAC Addresses

Address Resolution Protocol

ARP Table/Cache

Switchport Modes

Access Ports

Trunk Ports

Static Trunk

Dynamic Trunk

DTP

Dynamic Desirable

Dynamic Auto

Dot1q and ISL

SPAN

RSPAN

Broadcast Domain

Collision Domain

VLANS

Introduction to VLAN

Configure and verify basic VLAN configuration.

VTP: VLAN Trunking Protocol

VTP mode server

VTP mode client

VTP mode Transparent

VTP Updates

VTP Pruning

VTP Versions

Introduction to GVRP

Native VLAN

Private VLANS

Voice VLANS

Inter VLAN Routing

Inter VLAN routing with Access ports

Inter VLAN routing with Router on a Stick

Inter VLAN routing with SVI (MLS)

Inter VLAN routing with Routed and Non-Routed Ports

Concept of SVI

How to allow and block VLANs on trunk links

L2 Redundancy STP

Introduction to L2 redundancy

Infinite switching loops

Broadcast storm

Inconsistent MAC address table

Introduction to Spanning-tree protocol

Bridge-id

Root Bridge

Non-Root Bridge

Switch Role Election

Port Role Election

Root Port            

Designated Port

Non-Designated/Block Port

Impact of Bridge-id

Path Cost            

Sender’s Port-id

Per VLAN STP: PVST

PVST+  

Load-balancing and redundancy

STP Enhancements Protect STP Operations RSTP MST/MISTP

Implementing Portfast feature.

Implementing Uplinkfast

Implementing Backbonefast

BPDU Guard      

BPDU Filter        

Root Guard        

Loop Guard      

Understand & Implement RSTP

Understand & Implement MST

Link Aggregation Link Bundling EtherChannel L3 Redundancy

Introduction to link aggregation

Configure and verify EtherChannel

Port Channel

Channel Group

Static Implementation

Dynamic EtherChannel with Different Load-balancing techniques.

Introduce First Hop Redundancy

Hot Standby Routing Protocol

HSRP tracking

L3 Redundancy & Switch Security

Implementing VRRP

VRRP Object Tracking

Implementing GLBP

AVG      

AVF      

Implementing GLBP Object Tracking

Implementing Switch Port Security

DHCP Snooping

Dynamic ARP Inspection

VACL    

VLAN access-maps

[networkeducative]

IP Version-6 | IPv6

Introduction IPV6

IPv6 stances on behalf of web Protocol description six the importance of IPv6 makes its name clear, it's even as vital for the internet! The Internet Protocol commencing currently on for vital time is intended as a response to the necessity to attach a transparent knowledge affiliation, and has earned a “recognized” commonplace for multiple levels of communication. Currently IPs at totally different blocks will conduct and obtain continuous info, not solely on the net. Scientific discipline is owned by the Internet Engineering Task Force, the Connectors are all in danger for web principles acknowledging the link between programs from totally different representatives. However scientific discipline is that the commonplace, that is pointless, since these days everything affects the net victimization scientific discipline. Accessible scientific discipline to propel and obtain data. As a fragment of this "anything web related" is to (Internet of things), therefore currently you recognize why you're making an allowance for this facet of IPv6, one reasonably web Protocol these days, the best obligations to monitor and send and receive knowledge is thru the system for web use rules, together with scientific discipline. For why IPv6 exists intended. Acquire the IPv6 interconnected considerations that the remainder of the details are predicted to know. Provide a wise arrangement of IPv6, together with addresses associated a quick explore however an IPv6 web works.

If you want to read full content than visit our website by click below:

https://www.networkeducative.com/2021/11/internet-protocol-version-6.html

[networkeducative]

Transmission Types Half Duplex And Full Duplex | Half Duplex vs Full Duplex

A couple of different transmission types that are used in networking and those types are:

Half-duplex

Full-duplex

Half Duplex

so let's talk about half-duplex first so in a half-duplex network you have a point-to-point system where two devices are connected to each other using a network cable and these devices can communicate with each other in both directions but in a half-duplex they can only communicate in one direction at a time they cannot communicate in both directions at the same time so if computer a is sending data to computer B computer B has to wait until computer a is done before it can send data to computer a so data flows in one direction at a time the two computers have to take turns when they send data to each other so half duplex is just like how walkie-talkies work with walkie-talkies a person has to press a button if they want to talk to transmit their voice to the other person and while the button is pressed information is only going in one direction so they can't hear the other person while they're transmitting their voice they would have to release the button in order to receive the other person's transmission.

Full Duplex

Now full duplex is better in a full duplex the two devices can also communicate in both directions with each other but the difference is that they can communicate in both directions at the same time which gives full duplex an advantage over half duplex devices can send and receive data simultaneously so as a result because it sends and receives data at the same time a full duplex system has double the bandwidth of half duplex a good example of a full duplex would be telephone communication when you talk to somebody on the phone you can talk to and hear the other person at the same time so you don't have to wait to do one or the other you can talk and listen simultaneously.

Comparison Between Half-duplex and Full-duplex

so as a comparison between half-duplex and full-duplex you can use an analogy of cars on a highway where you have cars that travel across an area so when a half-duplex the cars would all have to share a single lane on the highway and that lane only allows traffic in one direction at a time the cars on the opposite sides of the highway would have to wait their turn to use that lane to get to their destination and since it only has one lane collisions do happen from time to time and that's why in a half-duplex network it needs a traffic cop to regulate that lane to tell cars to wait their turn and in networking this traffic cop is called csma/cd or carrier sense multiple access with collision detection and this is an access method that's used to help avoid collisions and to also respond correctly if a collision does happen and but in a full duplex the cars don't have to wait because you can compare a full duplex as having a two lane highway each Lane is dedicated for a direction the cars that are traveling in the opposite directions have their own dedicated lane as they travel to their destination and so as a result since each direction has their own dedicated Lane it avoids collisions and there is no need for a traffic cop now today we use full duplex networks a main reason why you would see a half duplex network today is for older legacy equipment that can only be used in half duplex mode for example if a network is still using hubs instead of switches because hubs can only operate in half duplex mode and not full duplex which is a main reason why hubs are obsolete today and you can't even buy them anymore.

[networkeducative]

What is a Firewall?

What is a Firewall?

A firewall is a system that is designed to prevent unauthorized access from entering a private network by filtering the information that comes in from the internet. A firewall blocks unwanted traffic and permits wanted traffic. So, a firewall's purpose is to create a safety barrier between a private network and the public internet. Because out on the internet, there's always going to be hackers and malicious traffic that may try to penetrate into a private network to cause harm. And a firewall is the main component on a network to prevent this. And a firewall is especially important to a large organization that has a lot of computers and servers in them. Because you don't want all those devices accessible to everyone on the internet where a hacker can come in and totally disrupt that organization. That's why you need a firewall to protect them. A firewall that's used in computer networks is very similar to how a firewall works in a building structure.

In fact, this is where the word 'firewall' came from. A firewall in a building structure provides a barrier so that in the event of an actual fire, on either side of a building, the firewall is there to keep the fire contained and to keep it from spreading over to the other side. So, the firewall is there to keep the fire from destroying the entire building. But if the firewall wasn't here, the fire would spread to the other side and the whole building would be destroyed.

And a network firewall works in a similar way as a structure firewall. It stops harmful activity before it can spread into the other side of the firewall and cause harm to a private network. In today's high-tech world, a firewall is essential to every home and especially a business or an organization to keep their network safe. A firewall works by filtering the incoming network data and determines by its rules if it is allowed to enter a network, these rules are also known as an access control list. These rules are customizable and are determined by the network administrator. The administrator decides not only what can enter a network but also what can leave a network. These rules either allows or denies permission.

So as an example, here we have some rules in a firewall's access control List and traffic from one IP address has been denied. So, if traffic from this IP address tried to get into this network, the firewall will deny it because of the rules that are set in the firewall. But the other IP addresses are granted access because the rules Allow them.

Firewall Rules

Firewalls don't just make rules based in IP addresses, but they can also make rules based on:

Domain names

Protocols

Programs

Ports

Keywords

Let's say in this example, the firewall rules are controlling access by port numbers. And let's say that the rules have allowed incoming data that's using port number 80, 25, and 110, and the data using those ports have been given access to this network.

So any incoming data that's using those ports, can pass through the firewall. But also in this firewall, the rules have denied any data that's using port numbers 23 and 3389. So, any incoming data that's using those port numbers, the firewall will deny access and it won't get passed the firewall. So, in a nutshell this is how firewalls basically work.

Firewalls come in different types:

One type is called a Host-Based Firewall

And this is a software firewall. This is the kind of firewall that is installed on a computer and it protects that computer only and nothing else. For example, later versions of Microsoft operating systems come pre-packaged with a host-baseball firewall. And you can see that example here. There are also 3rd party host-based firewalls can be purchased and installed on a computer. So, for example, Zone Alarm which is a popular 3rd party host-based firewall. And also, a lot of antivirus programs will have a built-in host-based firewall.

Another type of firewall is called a Network-Based Firewall

A network-based firewall is a combination of hardware and software, and it operates at the network layer. It is placed between a private network and the public internet but unlike a host-based firewall, where it only protects that computer, a network-based firewall protects the entire network, and it does this through management rules that are applied to the entire network so that any harmful activity can be stopped before it reaches the computers. Network-based firewalls can be a stand-alone product which is mainly used by large organizations.

They can also be built-in as a component of a router which is what a lot of smaller organizations rely on. Or they can also be deployed in a service provider's cloud infrastructure. Now, a lot of organizations will use both network- based and host-based of firewalls. They will use a network-based firewall to protect the entire network as a whole and they will also use host-based firewalls for their individual protection for their computers and servers. And by doing this, it'll ensure maximum protection. Because if harmful data just so happens to get passed the network firewall. The host-based firewalls on each computer will be there to stop it.

[networkeducative]

What is a Tri-Band Router?

What is a Tri-Band Router?

Let's see about first what a single and a dual-band router are. Now Wi-Fi routers broadcast a signal so that wireless devices such as laptops, tablets and phones can connect to access the internet. Now, a single-band router will only broadcast a single band and that frequency band is 2.4 GHz. And this is what the first wireless routers were, they were single-band routers. Now the 2.4 GHz band works pretty well but the problem is that when more and more devices connect to the Wi-Fi signal, the signal can become over-crowded and slow down the performance of the Wi-Fi speeds. And in addition to overcrowding, a lot of other devices, such as microwave ovens, cordless phones, and Bluetooth devices also use the 2.4 GHz band which causes a lot of interference. So, to help this problem of overcrowding, they came out with dual-band routers. And dual-band Wi-Fi routers broadcast two separate Wi-Fi bands. They broadcast the 2.4 GHz band and they also broadcast the newer 5 GHz band.

So, by broadcasting two separate bands, it's like having two separate networks in one device. So, you're going to have some devices connect to the 2.4 GHz band, which should be primarily your older and slower devices and you're going to have other devices connect to the 5 GHz band which would be your newer and faster devices. So, by separating your connected devices into two separate networks, it would help alleviate the problem of overcrowding and interference. But now they have tri-band routers and as its name implies, a tri-band router will broadcast three separate bands. It will broadcast a 2.4 GHz band and it'll also broadcast two separate 5 GHz bands. So, by having three separate bands in one router, you can have three separate networks for your devices to connect to which would help further solve the problem of overcrowding and interference.

Real Example for Understanding

So, to help illustrate this, you can think of a Wi-Fi band as a freeway. So, if you have a single lane on the freeway for traffic, then it might be okay if only a few cars use that lane. But the problem is when more cars want to use that lane, the freeway is going to be more congested and cause a slowdown. So, this would be like a single-band router but if you want to add an extra lane on that freeway for traffic, then the freeway would be less congested because the cars would have more lanes to use to get to their destination. So, this will be like a dual-band router. However, even a two-lane highway can get congested if more cars get on the freeway. Now what if you want to add a third lane to that freeway? So, by adding a third lane, then the freeway will be even less congested and the cars will clear faster and help eliminate any slowdown caused by excessive traffic. So, this example will be like a tri-band router. So, in a tri-band router we are going to have three lanes or three bands or three networks for all of the devices.

And this will help dramatically with the performance of your Wi-fi network. And in addition tri-band routers will also have a technology call "smart connect". And "smart connect" is a feature that intelligently assigns each wireless device to a wi-fi band where we can utilize its maximum speed. So, when your devices connect to your tri-band router, smart connect automatically separate your slower devices from your faster devices. So, it will put your slower devices on the 2.4 GHz band. Now slower devices like older laptops and wireless printers. And it will put your modern and higher speed devices on either one of the 5 GHz bands. So, this device will be like your modern laptops, tablets, phones, gaming consoles, and smart TVs. So smart connect intelligently chooses the best bands for all of your devices. And by doing this, it will make sure that your network is running at its maximum speed. So, who will need a tri-band router? Well, if you have a lot of wireless devices and I would say maybe between 10 and 15, I would highly recommend that you get one. Especially if you have more than 15 because you're going to see a big different and the performance of your network with a tri-band router.