In which network topology does every node connect independently to one central unit?

In which network topology does every node connect independently to one central unit?

• Bus
• Mesh
• Star
• Ring 

EXPLANATION

Star network a data or communication network in which all nodes are independently connected to one central unit

What is Star Topology?

A star topology is a network topology in which all the network nodes are individually connected to a central switch, hub or computer which acts as a central point of communication to pass on the messages.
In a star topology, there are different nodes called hosts and there is a central point of communication called server or hub. Each host or computer is individually connected to the central hub. We can also term the server as the root and peripheral hosts as the leaves.
In this topology, if nodes want to communicate with a central node, then they pass on the message to the central server and the central server forwards their messages to the different nodes. Thus, they form a topology like the representation of a star.

How does communication happen in a Star topology?

Let’s say all the computers of a floor are connected to a common hub or switch. The switch maintains a CAM table in this case. The CAM table is Content Addressable Memory where hardware addresses of the all the connected devices are stored inside a memory in the switch.
For example, if computer A wants to send a data packet to computer B then computer A will forward the message to the switch. The switch will check the address of the destination computer and forward the message to the same.
In the case of a hub, a hub has no memory of its own. So when computer A sends a message to computer B, then hub announces “Hello all the ports connected to me, I have got a packet for this address. Who of you has this address?” This procedure is called ARP (Address Resolution Protocol) and using this network protocol the hub is able to find the address of the intended machine and hence, it transfers the packet to the destination machine.

Advantages of Star Topology:

• Less damage in case of a single computer failure as it does not affect the entire network

Disadvantages of Star topology:

• More cables are required to be connected because each computer individually connects to the central server
• Single point of failure in case the server get down.

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Which PowerShell command should you use to get help with other commands?

Which PowerShell command should you use to get help with other commands?

• Get-Help
• /?
• -help
• -? 

EXPLANATION

The Get-Help cmdlet displays information about PowerShell concepts and commands, including cmdlets, functions, CIM commands, workflows, providers, aliases and scripts. To get help for a PowerShell command, type Get-Help followed by the command name, such as: Get-Help Get-Process.

Displays information about PowerShell commands and concepts.

Syntax

PowerShell

Get-Help
   [[-Name] <String>]
   [-Path <String>]
   [-Category <String[]>]
   [-Component <String[]>]
   [-Functionality <String[]>]
   [-Role <String[]>]
   [-Full]
   [<CommonParameters>]

 

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What does GPO stand for?

What does GPO stand for?

• Great Power Outage
• Group Policy Object
• Group Policy Overwrite
• Group Policy Output 

EXPLANATION

 A GPO when referring to Microsoft Technologies is short for a Group Policy Object. A Group Policy Object is a Policy object that is saved into Active Directory that can be applied to Users of Computers. The object itself has a list of settings that can be configured by an IT Administrator and then periodically (normally every 90 minutes) gets re-applied to the computer.

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Layer 4 in the OSI model corresponds to which of the following?

Layer 4 in the OSI model corresponds to which of the following?

• Network layer
• Transport layer
• Physical layer
• Presentation layer 

EXPLANATION

 

Transport layer

The Transport  layer is also called as the layer 4 of the OSI model. Here are the basic functionalities of the Transport layer:

• Responsible for the transparent transfer of data between end systems
• Responsible for end-to-end error recovery and flow control
• Responsible for complete data transfer.
• Protocols like SPX, TCP, UDP work here

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The OSI model consists of how many layers?

The OSI model consists of how many layers?

• 7
• 6
• 5
• 8 

EXPLANATION

The 7 Layers of the OSI

In the OSI model, control is passed from one layer to the next, starting at the application layer (Layer 7) in one station, and proceeding to the bottom layer, over the channel to the next station and back up the hierarchy. The OSI model takes the task of inter-networking and divides that up into what is referred to as a vertical stack that consists of the following 7 layers.
Note: Click each hyperlink in the list below to read detailed information and examples of each layer or continue scrolling to read the full article:

• Layer 7 - Application
• Layer 6 - Presentation
• Layer 5 - Session
• Layer 4 - Transport
• Layer 3 - Network
• Layer 2 - Data Link
• Layer 1 - Physical

 

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In Linux, the rmdir command (without any flags):

In Linux, the rmdir command (without any flags):

• Removes a directory and its contents
• Removes empty directories
• Removes a directory and all of its subdirectories
• Remotely creates a directory 

EXPLANATION

 

rmdir

Remove directory, this command will only work if the folders are empty.

Syntax
      rmdir [options]... folder(s)...

Options
      --ignore-fail-on-non-empty
                  Ignore each failure that is solely because the
                  directory is non-empty.

  -p, --parents   Remove explicit parent directories if being emptied

      --verbose   Output a diagnostic for every directory processed

      --help      Display help and exit

      --version   Output version information and exit

Example

$ rmdir myfolder

Before removing directories with a wildcard, it's wise to list them first:

$ ls -d britney*/

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Which of the following is a valid command in Linux?

Which of the following is a valid command in Linux?

• w
• x
• t
• y

EXPLANATION

Thw w command display who is logged into the Linux and Unix-like server, and what they are doing at command execution time. The syntax is:
w
I suggest that you either read Linux w command examples page or see Linux w command man page for more information.

When you type "man {name of command}" in terminal, you most often will get info from the Linux Manual on that command (note: do not enter the brackets when typing the command). i.e - man w
NAME w - Show who is logged on and what they are doing.

SYNOPSIS w [-husfVo] [user]

DESCRIPTION
w displays information about the users currently on the machine, and their processes. The header shows, in this order, the current time, how long the system has been running, how many users are currently logged on, and the system load averages for the past 1, 5, and 15 minutes.
The following entries are displayed for each user: login name, the tty name, the remote host, login time, idle time, JCPU, PCPU, and the command line of their current process.
The JCPU time is the time used by all processes attached to the tty. It does not include past background jobs, but does include currently running background jobs.

 

 

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