LearnF9

What is LAN?

2020-05-24T17:18:00.001+05:30

What is LAN?

A LAN is a local area network which interconnects network components present geographically close to each other or you can say all the Local area network to connect close devices to each other such as in a single room, the floor of a building, within a building or on campus.
LAN can span from very small sizes, like small office/home office, to a large corporation or in an Enterprise environment.
Basically a LAN infrastructure is owned by a company or organization to share its devices or resources in a local area with the help of the network.

What are the components of LAN?

Common components you can see in a LAN network is Computers/PCs, Laptops, and servers.
Networking components like Router, Switch, Hub, firewall Access Point, IDS/IPS, and many more.
Also NIC and media type like wired or wireless also the components of LAN.
The protocol mostly used in LAN is "Ethernet protocol" to share resources and data.
"Ethernet" is by far the most common type of LAN protocol.

What is the Function of LAN?

The main function of all of these LAN components is to allow users to access applications and data, to share resources like printers and storage devices, computers to connect to other network components to share information and utilize resources in the LAN network.

Today Ethernet is the most common Layer 2 protocol implemented in a company network.

Examples of LAN technologies.

Ethernet, Token Ring and Wireless (WLAN) using The Institute of Electrical and Electronics Engineers (IEEE) 802.11 are examples of standard LAN technologies.

LAN Topologies:

LAN has the following topologies:

· Star Topology

· Bus Topology

· Ring Topology

· Mesh Topology

· Hybrid Topology

· Tree Topology

What is IPv4, IPv6 Addresses and where IPv5 Internet Protocol Address is?

2020-03-27T11:16:00.002+05:30

IPv4 Address:

IPv4 (Internet Protocol version 4) was the first publicly used version of the internet protocol. An internet protocol is the set of rules that govern how packets are transmitted over a network. IPv4 was developed as a research project by the Defence Advanced Research Projects Agency (DARPA), a United States Department of Defence agency, before becoming the foundation for the Internet and the World Wide Web. IPv4 includes an addressing system that uses numerical identifiers consisting of 32 bits. The format of IPv4 addresses is the ###.###.###.### format, which is made up of four numerical octets (a unit of digital information in computing consisting of eight bits), with each set ranging from 0 to 255 and separated by periods. Thus, IPv4 provides an addressing capability of 232 or approximately 4.3 billion addresses.

IPv6 address:

IPv6 (Internet Protocol version 6) is the most recent version of the Internet Protocol (IP), the communications protocol that provides an identification and location system for computers on networks and routes traffic across the Internet. IPv6 was developed by IETF i.e. Internet Engineering Task force to deal with the biggest problem of IPv4 address exhaustion.

IPv6 was developed in the 1990s to solve the addressing limitation, and commercial deployment of this new internet protocol began in 2006. IPv6 is a 128-bit protocol, and it provides vastly more IP Addresses. The format of IPv6 is a series of eight 4-character hexadecimal numbers; each of these represents 16 bits, for a total of 128 bits. The characters in an IPv6 address is numbers from 0 to 9 and letters from A to F.

An example of an IPv6 address is 2001:0db8:0000:0000:1234:0ace:6006:001e. IPv6 has the capacity to offer trillions upon trillions of IP addresses (as many as 3.4x1038 addresses) with little chance of running out.

IPv6 is developed to overcome the problem of IPv4. In December 1998, IPv6 became a Draft Standard for the IETF, who subsequently ratified it as an Internet Standard on 14 July 2017.

We know IPv4 and IPv6 but ever wondered where IPv5 Internet Protocol Address is?

As I said above, an internet protocol is the set of rules that govern how packets are transmitted over a network. IPv5 is also a version of internet protocol (IP) IPv4 and IPv6 that was never formally adopted as a standard.

The v5 stands for version 5 of the Internet Protocol. Usually, Computer networks use version 4, typically called Ipv4, or a newer version of IP called Ipv6. IPv5 that was also known as Internet Stream Protocol, abbreviated simply as ST. It was designed for connection-oriented communications across IP networks with the intent of supporting voice and video.

One shortcoming that undermined its popular use was its 32-bit address scheme – the same scheme used by IPv4. As a result, it had the same problem that IPv4 had – a limited number of possible IP addresses.

ST was effective at transferring data packets on specific frequencies while maintaining communication. It would eventually serve as a foundation for the development of technologies such as voice-over-IP, or VoIP, which is used for voice communications over the internet.

IPv5 used the same IPv4's 32-bit addressing, which eventually became a big problem for IPv5. The format of IPv4 address is the ###.###.###.### format, which is made up of four numerical octets with each set ranging from 0 to 255 and separated by periods. This format allowed for 4.3 billion internet addresses; however, the rapid growth of the internet soon exhausted this number of unique addresses. By 2011, the last remaining blocks of IPv4 addresses were allocated. With IPv5 using the same 32-bit addressing, it would have suffered from the same limitation.

So, IPv5 was abandoned before ever becoming a standard, and the world needs to move on to IPv6.

What is VGA and HDMI cable?

2020-03-25T16:20:00.000+05:30

What is VGA and HDMI cable?

VGA and HDMI are interface standards used for cables that connect devices — such as laptop computers and DVD players — to a display, like a TV, computer monitor or projector.

HDMI:

HDMI (High-Definition Multimedia Interface) is a proprietary audio/video interface for transmitting uncompressed video data and compressed or uncompressed digital audio data from an HDMI-compliant source the device, such as a display controller, to a compatible computer monitor, video projector, digital television, or digital audio device. HDMI is a digital replacement for analog video standards.

The HDMI standard allows for the transfer of both digital video and audio signals via the same interface (port) and cable, capable of providing high-definition (HD) video at resolutions of 1,920 x 1,200 pixels and 8 audio channels simultaneously. Because it supports digital copy protection of all signals, HDMI cables are included for devices such as the Apple TV, Blu-Ray players, and game consoles, among other similar electronic products.

Pin ut

HDMI type A receptacle
Pin 1	TMDS Data2+
Pin 2	TMDS Data2 Shield
Pin 3	TMDS Data2−
Pin 4	TMDS Data1+
Pin 5	TMDS Data1 Shield
Pin 6	TMDS Data1−
Pin 7	TMDS Data0+
Pin 8	TMDS Data0 Shield
Pin 9	TMDS Data0−
Pin 10	TMDS Clock+
Pin 11	TMDS Clock Shield
Pin 12	TMDS Clock−
Pin 13	CEC
Pin 14	· Reserved (HDMI 1.0–1.3a) · Utility/HEAC+ (HDMI 1.4+, optional, HDMI Ethernet Channel and Audio Return Channel)
Pin 15	SCL (serial clock for DDC)
Pin 16	SDA (serial data for DDC)
Pin 17	Ground (for DDC, CEC, ARC, and HEC)
Pin 18	+5 V (min. 0.055 A)
Pin 19	· Hot Plug Detect (all versions) · HEAC− (HDMI 1.4+, optional, HDMI Ethernet Channel and Audio Return Channel)

VGA:

VGA connectors and cables carry analog component RGBHV (red, green, blue, horizontal sync, vertical sync) video signals and VESA Display Data Channel (VESA DDC) data.

A Video Graphics Array (VGA) connector is a three-row 15-pin DE-15 connector. The 15-pin VGA connector was provided on many video cards, computer monitors, laptop computers, projectors, and high definition television sets. On laptop computers or other small devices, a mini-VGA port was sometimes used in place of the full-sized VGA connector.

VGA is an older standard that carries only a video signal. HDMI is the default cable standard for newer electronic devices, such as Blu-Ray players or LED TVs. HDMI can carry both digital video and audio signals, all while encrypting data with HDCP.

The video quality attained with a VGA cable is noticeably worse when compared to that of HDMI.

in out

A female DE15 socket.
Pin 1	RED	Red video
Pin 2	GREEN	Green video
Pin 3	BLUE	Blue video
Pin 4	ID2/RES	Reserved since E-DDC, formerly monitor id. bit 2
Pin 5	GND	Ground (HSync)
Pin 6	RED_RTN	Red return
Pin 7	GREEN_RTN	Green return
Pin 8	BLUE_RTN	Blue return
Pin 9	KEY/PWR	+5 V DC (powers EDID EEPROM chip on some monitors), formerly key
Pin 10	GND	Ground (VSync, DDC)
Pin 11	ID0/RES	Reserved since E-DDC, formerly monitor id. bit 0
Pin 12	ID1/SDA	Data since DDC2, formerly monitor id. bit 1
Pin 13	HSync	Horizontal sync
Pin 14	VSync	Vertical sync
Pin 15	ID3/SCL	Clock since DDC2, formerly monitor id. bit 3
The image and table detail the 15-pin VESA DDC2/E-DDC connector; the diagram’s pin numbering is that of a female connector functioning as the graphics adapter output. In the male connector, this pin numbering corresponds with the cable’s wire-and-solder side.

VGA vs. HDMI Capabilities:

HDMI is a digital cable. VGA is analog. VGA cables can have degrading quality within the cables and make picture quality poorer. On the other hand, HDMI is all digital, so quality is not at all affected. HDMI either works entirely or doesn't work at all. This is also why overpriced HDMI cables aren't worth it. There is no picture quality difference whatsoever. Sometimes you might want a better HDMI cable if it's moved a lot and needs to be more rugged, but otherwise its best to get the cheapest one. VGA is more hit and miss.

What is Split Horizon?

2020-03-24T10:36:00.000+05:30

What is Split Horizon?

Split horizon is a method of preventing a routing loop in a network.

Meaning whenever loop formation occurs in the network Split horizon will prevent that. Now how it will prevent loop formation, the basic principle behind the split-horizon is that the routing source of any packet will never send back to its source from which it is generated.

Split Horizon in RIP:

Distance vector protocols (RIP and EIGRP) are more susceptible to routing loops. Routing loops occur when a packet is continually routed through the same routers over and over in repetition and forms loop.

Split horizon is one of the methods used by distance vector routing protocols to avoid routing loops. This is achieved as – a router will not advertise a route back onto the interface from which it was learned. Split horizon is enabled on interfaces by default.

To consider what could happen without the split-horizon mechanism, take a look at the following example:

We let us assume that we have a network of three routers (R1, R2, and R3). All routers are running RIP Protocol, i.e. a distance vector protocol. R3 is directly connected to the 10.0.0.0/24 network and advertises that network using RIP to R2. R2 receives the routing update from R3, places the route in its routing table and informs Router R1 about the 10.0.0.0/24 network.

Now because the split-horizon mechanism is enabled by default on all interfaces, R1 will not advertise to R2 that it has the route to 10.0.0.0/24 network in its routing table. And here split horizon prevents the formation of the Routing loop in the network.

What if Split Horizon will not present:

Now consider what would happen if the split-horizon mechanism didn’t prevent Router R1 to advertise the route back to Router R2. Router R1 would advertise to Router R2 that it has a route to reach the 10.0.0.0/24 network. Let’s say that the link between the Router R2 and Router R3 fails. Since Router R2 received a route to that network from Router R1, it will send all packets destined for the 10.0.0.0/24 network to router R1. But Router R1 thinks that Router R2 has a route to reach that network (it doesn’t know that the link between Router R2 and Router R3 failed) and sends the packets back to Router R2, thereby creating a routing loop.

What is Sticky Keys?

2020-03-17T21:57:00.000+05:30

What are Sticky Keys?

Most of us by mistake press many times SHIFT Key during playing games, editing videos or photos, or doing many other things on our computer and suddenly get a new window asking that “do you want to turn on Sticky Keys?”

Now the question is what Sticky Keys is and how we get this window which is asking “do you want to turn on Sticky keys?” Many of us don’t know what this Sticky key is and we simply close this popup without checking it what Sticky Key is.

In case if you don’t know, no need to worry. It will not hamper anything in your system if you open or close it. And I believe after reading this article you will know all about what sticky keys is.

Sticky Keys:

Sticky Keys is a feature available in your Laptop/Desktop Operating System to provide ease to their users who have physical disabilities or help users to reduce repetitive strain injury. Sticky Keys was introduced by MAC and Microsoft back in the 90s.

Sticky keys enable the user to enter key combinations i.e. Shift, Ctrl, Alt, Windows logo key in sequence rather than simultaneously. In simple words, with this cool feature there is no need to press Ctrl, SHIFT, Alt and Windows logo key with other alphabet keys to perform your task.

For example: If you are typing something on the MS Word page and you need to select everything in your page, you just use Ctrl + A key to copy all and to paste the same in new the page you use Ctrl + V key to paste that. So here you use a combination of Ctrl and another key simultaneously to perform the task.

Here these Sticky Keys feature helps those who are unable to press these keys combinations simultaneously and give the option to click them one by one and perform the same task.

Think if you have an injury on one hand and because of any reason you are not able to press these key combinations then, in that case, you will not be able to complete your task but with this sticky key, you can use this key combination as a normal key and use sequentially.

Now when we know what sticky keys are so it is obvious that you will curious to know how to enable sticky keys in your system.

How to Turning on Sticky Keys:

There are two ways to enable the sticky keys, ease of access feature in your system, let’s check the easiest way first.

First Method:

You can directly use Sticky key, you just need to Press “Shift Key” five times to enable it. A popup on your screen will come with sound and will ask you “Do you want to turn on Sticky keys?”

Click on Yes and it will enable. Isn’t it so simple?

Second Method:

1. Click on the start menu.

2. Type control panel in type here to search.

3. Click on Control Panel.

4. Click on Ease of Access.

5. Click on Ease of Access center.

6. Click on Make the keyboard easier to use.

7. Go to make it easier to type.

8. Check turn on Sticky Keys.

9. Click on Set up Sticky keys.

10. Check Turn on sticky keys when SHIFT is pressed five times.

11. Click on Apply

12. Click on OK.

Here your cool Sticky Keys feature is enabled.

Now how you will Know It is enabled or not, so to check it is enabled or not check below:

How to check Sticky Key is working or not:

If the sticky key is enabled you will get sound whenever you press any of these combination keys. (Shift, Ctrl, Alt, Windows logo Key). Microsoft Windows will play a sound or you will see an icon in your Taskbar containing four keys combination.

Now if you want to close this Sticky Key feature follows the below steps.

How to Turn Off Sticky Key:

1. Click on the start menu.

2. Click on Control Panel.

3. Click on Ease of Access.

4. Click on Make the keyboard easier to use.

5. Go to make it easier to type.

6. Click on Set up Sticky Keys.

7. Uncheck this Turn on sticky key when SHIFT is pressed five times.

8. Click on Apply.
9. Click on OK.

I hope after reading this article you will understand about sticky Key feature and I am capable enough to explain this to all of you.

How to install GNS3

2020-03-16T21:18:00.000+05:30

How to install GNS3:

Step 1: You can directly download GNS3 setup from GNS3 website or below link. https://www.gns3.com/software/download

Step 2: I am Installing GNS3-2.2.5-all-in-one-regular for Windows; you can select and download the GNS3 setup as per your OS.

Step 3: Click on Next and start the installation of GNS3.

Step 4: Click on I agree to accept the terms of Agreement.

Step 5: Click on Next, (no need to change anything here).

Step 6: Select the Components that you need to install.

(I am unselecting Solar-putty, VirtViewer, TightVNC Viewer, CPU limit)

Step 7: Select the Destination folder where you want to install GNS3.

Step 8: You will get a new dialog box to install WinPcap, to install it click on next.

Step 9: Click on I Agree.

Step 10: Click on install to install WinPcap.

Step 11: WinPcap installation is finished now. We need to go back to the GNS3 installation.

Step 12: After the completion of WinPcap installation you will see the on-going installation process of your GNS3 software (wait it will take some time).

Step 13: Once done you will get the installation complete message on the screen.

Click on next.

Step 14: Check “No” for Solarwinds Standard toolset installation, Click on next.

Step 15: You will get the dialog box of completing GNS3 2.2.5 setup, click on Finish.

It will open GNS3.

Congratulations your GNS3 Installation is done. Now you can install CISCO IOS for your Lab Practical Scenarios and make yourself confident enough to achieve success.

How to install VMware Workstation

2020-03-15T21:44:00.001+05:30

How to install VMware:

Step 1: Download VMware workstation, you can download it directly from below link:

https://www.vmware.com/in/products/workstation-pro/workstation-pro-evaluation.html

Step 2: After downloading setup, double Click on the setup and start installing VMware in your machine.

Step 3: Click on Next and proceed

Step 4: Check the box and accept the license agreement, click on next.

Step 5: Click on Change if you want to the installation directory otherwise click on next.

Step 6: Click on Next and if you want you can check the box for updates.

Step 7: Click on next

Step 8: Click on Install

Step 9: Click on Finish.

Step 10: Once click on finish, you will get the below Thank you dialog box from VMware Workstation.

Now you have successfully installed VMware in your machine.

Note: A journey of a thousand miles begins with a single step.

And believe me, my dear friend if you have faith in you, you are already one step ahead of your competitors.

OSPF Routing Protocol

2020-03-13T12:07:00.001+05:30

OSPF Routing Protocol:

It is an open shortest path first routing protocol, or also known as a link-state routing protocol.
AD value is 110, the cost for FastEthernet is 1 i.e. (100Mbps/cost of bandwidth in Kbps)
OSPF has an unlimited hop count
OSPF provides flexible, Fast and scalable routing protocol, its convergence time is fast.
OSPF establishes neighbourship to share the routing tables or its Database.
OSPF is configured on Interfaces, not on the router.
OSPF supports VLSM/CIDR
Works on both IPV4 and IPV6
Works on Dijkstra Algorithm.

OSPF mechanism:

OSPF generates and sends Hello Packet
Establishes Neighborship.
Shares database.
Form Adjacencies.

Loopback interfaces

2020-03-12T22:28:00.000+05:30

What Are Loopback Interfaces and why we use loopback interfaces in OSPF routing protocol:

Loopback interfaces are logical interfaces, which are virtual, software-only interfaces; they are not real router interfaces.

In networking, we create Loopback interfaces on the router which serves in many ways. Loopback interfaces never go down until and unless the administrator intentionally shutdown it. Loopback interfaces do not require any type of medium eg. ethernet cables to connect so it is always up by default after creating a loopback interface in global configuration mode.

Loopback Interfaces play a major role in the OSPF routing protocol. Using loopback interfaces with your OSPF configuration ensures that an interface is always active for OSPF processes. They can be used for diagnostic purposes as well as OSPF configuration. the highest Loopback interface is selected as Router ID in OSPF if we have not configures any manual id on the interface.

In Computer, The Loopback Interfaces is a virtual network that your computer uses to communicate with itself. It is used mainly for troubleshooting and to connect to servers running on the local machine. The loopback IP address is 127.0.0.1.

with the Help of loopback interface address i.e 127.0.0.1, you can troubleshoot and ensure during network issue as a primary troubleshooting step that everything is fine and working at your Machine end i.e your ethernet adapter is working or not before going to troubleshoot on another device.

For IPv4, the loopback interfaces is assigned all the IPs in the 127.0.0.0/8 address block. That is, 127.0.0.1 through 127.255.255.254 all represent your computer. For most purposes, though, it is only necessary to use one IP address, and that is 127.0.0.1. This IP has the hostname of localhost mapped to it.

For Self Testing follow the steps:

Open CMD as Administrator

Type ping 127.0.0.1

Make sure the host is not connected to any of the networks.