8 posts categorized "Viavi" Feed

LMTV LIVE | Wireshark Week (with Brad Reinboldt and Tony Fortunato)

Wireshark_email_header_17_200_3This week Tim, Tony and Denny spoke with an old friend, Brad Reinboldt, Senior Solutions Manager from Viavi Solutions, about their upcoming free education webinar series Wireshark Week.

We looked at the challenges of getting started with Wireshark, uncover quick tips from Tony that make troubleshooting in Wireshark easier, and talk about other tools that work alongside Wireshark to simplify root-cause analysis. Additionally, Brad went into detail on the Wireshark web sessions offered from November 6-11.

For more information, click here to sign up for Wireshark Week

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Network Troubleshooting Through the OSI Model (by Melany Joy Beck)

Network Troubleshooting Through the OSI Model

When it comes to network troubleshooting, working through the Open Systems Interconnection (OSI) model is a straightforward process. With the exception of Layer 1, each layer of the OSI model relies on the next lower layer to provide services as specified. Requests drop down and are completed, as every layer interacts with the next layer, both above and below. When dealing with different layers, understanding how each delivers data and functions impacts how you will troubleshoot.


Viavi guide to enterprise protocols poster – Get yours today. 

Viavi free osi

Layer Highlights and Functions - A complete view from Layer 1 through Layer 7!

Read on to see each layer overview and more free links below - 


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The Payoff of having a double sided capture! (by Mike Motta)

The complaint came in that it was taking from 4 to 20 minutes to transfer data.

Why is the network slow?  Is it the network?

Could it be the infamous SNAIL problem?


At first the client sent me a trace only from the client side.  The trace file showed packets out of order and some re-transmissions along with low TCP windows.  I asked the client if it was possible to get a capture from both sides, client and server and the answer was “yes” (In my world that is the best way to eliminate any magic!)  

First: I looked at the server side trace file first.  It showed the server re-transmitting over a thousand times.  (Uh Oh)   

By having both sides I was able to prove that the server did indeed send the packet but the client did not receive it. 

We can also see that they are 5 hops from each other, which means something is dropping packets. 

Next : It is time to interrogate router interfaces and firewall interfaces for discards or drops. 

Watch this Video for the problem visibility process, guiding us to the issue at https://youtu.be/WW0SjeeteK8 

Get a TAP to see every bit of your Data!


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LMTV LIVE | Networking Trends for 2017 (with Mike Canney of Viavi)

Live Broadcast starts @ 9:30 AM PST, Wednesday, January 11, 2017

ViaviMike canneyWith the New Year’s celebrations behind us, it’s time to put down the eggnog and look forward to the key technologies and trends that will impact network professionals in 2017.

LMTV will kick off this year with Mike Canney, Principal Strategic Architect and troubleshooter of Viavi Solutions, to take a look into our crystal ball to discuss the biggest things to impact IT.

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Why Packetheads Need Not Fear Cisco ACI (by Mike Canney)

Why Packetheads Need Not Fear Cisco ACI

There seems to be much mystique and confusion over Cisco’s ACI and how we as network analysts will troubleshoot in this new network environment. It’s an architecture to which few seem to have completed the move, but many are planning to do so in the near future. Now is the time to architect with visibility in mind.


With Cisco ACI there has been some misunderstanding based on early claims of ‘not needing packets anymore’ to discussions on ’how the heck are we going to do this?’ Eager to confirm my beliefs about ACI, I attended many sessions at the Cisco Live conference this year. There was a lot of clarification and confirmation of how to best instrument new networks for full visibility. 

The Short Answer:  Not much has changed as far as building a visibility fabric. If you have familiarity with building such a fabric in the VMware Nexus ‘Top of the Rack’ design, you will have no issue capturing in an ACI environment. Wherein the Nexus model, to get east-west traffic, you would simply tap the uplinks between the top of the rack and the aggregation layer, in an ACI environment you tap between the spine and leaf switches to obtain traffic. 


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