The Multiple Spanning Tree Protocol (MSTP) was originally defined in what IEEE Standard?

The Multiple Spanning Tree Protocol (MSTP) was originally defined in what IEEE Standard?

• IEEE 802.1Q-2005
• IEEE 802.1w
• IEEE 802.1D
• IEEE 802.1s 

EXPLANATION

The Spanning Tree Protocol (STP) is a network protocol that builds a loop-free logical topology for Ethernet networks. The basic function of STP is to prevent bridge loops and the broadcast radiation that results from them. Spanning tree also allows a network design to include backup links to provide fault tolerance if an active link fails.

As the name suggests, STP creates a spanning tree within a network of connected layer-2 bridges, and disables those links that are not part of the spanning tree, leaving a single active path between any two network nodes. STP is based on an algorithm that was invented by Radia Perlman while she was working for Digital Equipment Corporation.^[1][2]
In 2001, the IEEE introduced Rapid Spanning Tree Protocol (RSTP) as 802.1w. RSTP provides significantly faster recovery in response to network changes or failures, introducing new convergence behaviors and bridge port roles to do this. RSTP was designed to be backwards-compatible with standard STP.
STP was originally standardized as IEEE 802.1D but the functionality of spanning tree (802.1D), rapid spanning tree (802.1w), and multiple spanning tree (802.1s) has since been incorporated into IEEE 802.1Q-2014.^[3]

 

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In telecommunications, the CBR is used to determine the quality of service. What does CBR stand for?

In telecommunications, the CBR is used to determine the quality of service. What does CBR stand for?

• Clipped Beard Regret
• Central Board Ratio
• Closed Bit Ratio
• Constant Bit Rate 

 

EXPLANATION

Constant bitrate (CBR) is a term used in telecommunications, relating to the quality of service. ... CBR is useful for streaming multimedia content on limited capacity channels since it is the maximum bit rate that matters, not the average, so CBR would be used to take advantage of all of the capacity.

 

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What's a VBR?

What's a VBR?

• Vacation Builds Sanity
• Visual Basic Remote
• Variable Bit Rate
• Volume Boot Record 

EXPLANATION

A variable bit rate (VBR) is an encoding method that is used mainly in communications and computing to achieve improved audio quality in comparison to file size ratio. Depending on the nature of the audio, the bit rate is continuously changed during the encoding process to achieve the VBR.


VBR is most commonly used in the transmission of compressed audio and video data, such as videoconferencing.

Variable Bit Rate (VBR)

Using the variable bit rate (VBR) method has advantages and disadvantages.

VBR advantages are as follows:

• Compared to a constant bit rate (CBR), VBR produces a better quality-to-space ratio for the same file size.
• The available bits are used to more flexibly and accurately encode the audio or video data.
• Higher bits are used in more difficult to encode passages and lower in less demanding passages.

VBR disadvantages are as follows:

• The encoding process requires more time.
  
• The VBR process is more complex and thus more susceptible to errors.
  
• Hardware compatibility can be an issue.
  

VBR encoding types include:

• Quality-based VBR encoding: The focus is on a specific quality level for the media stream and not the bit rate. This encoding also ensures that the generated file has a consistent quality. However, because this encoding cannot provide required size and bandwidth criteria, it may not be suitable for those with restricted memory or bandwidth, like portable media players.
  
• Unconstrained VBR encoding: This makes use of two encoding passes. Like CBR, unconstrained VBR encoding uses a specific bit rate, which is used as an average bit rate. Unconstrained VBR encoding's main advantage is the ability to provide the highest quality for the compressed stream, while remaining within an assumable bandwidth.
  
• Constrained VBR Encoding: This allows the specification of a maximum and minimum bit rate. Using the maximum values, the codec then determines and compresses the data.

 

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Which of the following PowerShell commands is equivalent to the "ipconfig /flushDNS" command?

Which of the following PowerShell commands is equivalent to the "ipconfig /flushDNS" command?

• Clear-DNSClientCache
• Clear-DNSCache
• Remove-DNSRecords
• Delete-DNSCache 

 

EXPLANATION

Clear and Flush DNS with PowerShell

You can use the following command to clear the DNS cache on a Windows system using PowerShell

 
Clear-DnsClientCache

Show DNS Cache with PowerShell

There is also a PowerShell command to show you the DNS cache:

 
Get-DnsClientCache

 

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What does HTTP stand for?

What does HTTP stand for?

• Hyper Text Markup Language
• Hyper Text Transfer Protocol
• HyperTexting Transfer Protocol
• Hypertext Transfer Protocol 

EXPLANATION

 HTTP - HyperText Transfer Protocol. HTTP means HyperText Transfer Protocol. HTTP is the underlying protocol used by the World Wide Web and this protocol defines how messages are formatted and transmitted, and what actions Web servers and browsers should take in response to various commands

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