91 posts categorized "Wireshark" Feed

Slow Transfer, Packet Losses, Congestion Avoidance, Shaping and Policing (by Phil Storey)

Problem: Slow Transfer, Packet Losses, Congestion Avoidance, Shaping and Policing!

This is a response to a question asked on Tuesday 5th December by “u/thegreattriscuit” in Reddit’s “r/Networking” subreddit.

The original question that started the investigation! Click to go to page -

Question Summary - The problem was slow file transfer throughput across a long 1 Gbps WAN (“across an ocean”) and caused by packet losses. However, we’re told that the packet loss behaviour was consistent and readily reproducible for this particular iPerf test - but not apparent for other transfers across the same link.

The provided “topology” diagram is below. The flow is from Host-A at the left to Host-Z on the right and the packet losses occur somewhere between the two points (as indicated by the blue line between two capture points). The losses could be within the Cisco 4500, ASR1000, Force10 WAN, ASR1000 or Force10 switch).

1

A commercial packet analysis tool called NetData Pro was used to perform this analysis and provide the detrail visuals included - 

Full Details of the analysis and Conclusions following - 

*Note for larger diagrams click on image - 

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IoT: Tesla Model S Remote Control (by Jonathan Whiteside, Darrin Roach and Paul Offord)

With the proliferation and expansion of wireless technologies, it is now becoming commonplace for vehicles to be connected to the Internet for numerous reasons, such as website access, telematics and always connected emergency services.

Tesla Motors is very much at the forefront of the ‘Connected Vehicle’ revolution, producing vehicles with ‘always on’ connectivity through 4G LTE and WiFi.  This gives the driver features such as Google Maps navigation, web access and Spotify.

Tesla_control

It also allows remote operation features such as climate control and charge port opening/closing, as well as providing an instant view of battery charge levels.  All these features can be readily accessed from a mobile phone app or desktop app on a PC.

The objective of this experiment was ...

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Wireshark Fundamentals (by Tony Fortunato)

I am noticing that i am  seeing a lot of people who are self taught when it comes to Wireshark and protocol analysis as well as those who want to get into it.

I decided to create a 2 hour Udemy (Wireshark Fundamentals) course to teach people Wireshark basics and in the last lecture Idemonstrate how to get started with protocol analysis.

The key is to demonstrate why and when to use a feature. Knowing where the features are doesn't imply you know when and why to use them.

I encourage anyone interested in protocol analysis to get familiar with cause and effect. That is where you simply do something and review those packets.

Last month had a draw for free coupons to take my class and thought it would be cool to post an entire lecture from the course.  Enjoy.

 

 

 

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How TCP Works - No-Operation (by Chris Greer)

Hey packet people! 

If you have ever had to analyze a TCP connection, you have definitely seen a three-way handshake. In that handshake, both TCP stacks will exchange the options they are open to use for the connection. In the options field, you may also see several instances of the No-Operation value. 

How does this value work? What does it mean (other than no-operation of course), and how should I interpret it? 

Get the answers to these questions here:

 

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Wireshark Udemy Free Course Giveaway (by Tony Fortunato)


I have been presenting, training, creating videos, articles and sharing information for over 20 years. As technology evolves, I have tried to keep up by creating lovemytool google and linkedin groups as well as contributing to many social media technical groups/online publications.

When youtube started becoming a source of information for technicians, i created a channel. My youtube channel has over 330 videos covering various topics such as Microsoft operating system, Cisco, Wireless, Wireshark and other technical topics.

I will not be teaching or presenting this year (so far) so i thought i would take some of the suggestions sent to me last year. I had several requests to create some online material so I created a "Wireshark 2 Fundamentals" class on Udemy as my first attempt. This is introductory class for those who want to start using Wireshark or if you need a refresher.

No need to be intimidated by Wireshark! Many IT analysts avoid getting into Wireshark because it seems overwhelming.  You don't need a lot of experience to get up and running with Wireshark. In this course you will learn all the basics required to confidently capture, save and navigate around Wireshark's environment. I will spend some time explaining enough of the software to encourage you to use it more.

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