439 posts categorized "Test & Measurement" Feed

Layer 1 Troubleshooting Scenario (by Tony Fortunato)

In this article I wanted to review a current troubleshooting scenario that I thought you would benefit from.  The point of the article is that you should never overlook the basics.

While working onsite, I overheard a group of technicians discussing a current issue with a WiFi radio on a tower. Their management system reported that the radio was down and probably had to be replaced. One of the issues is that they have to get a hold of someone to climb the tower which means that the outage only gets longer. After they located someone I asked what was going on.

The senior analyst explained that his happens every so often and the radio just needs to be replaced with a new one.  I then asked if they would mind showing me around since we were just waiting for the contractor and they said no problem.

We walked over to the bottom of the tower, opened the enclosure and noticed that smell of burnt popcorn. There obviously wasn’t any popcorn there, that’s just my way of describing the smell of burnt cable or electronics. After some poking around, I determined that they needed to replace a lot more than just the radio.  In the video, I explain what I looked for, what I found and what I suggested. 

While waiting for the contractor, i also suggested that we review their grounding.

 

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Testing POE with Pockethernet (by Tony Fortunato)

Its important for analysts to have basic tool to test their equipment and cables.

The other day I needed to replace a POE injector on a roof and wanted to make sure that the one I found in my box of goodies actually works.

I’ve been in many situations where the equipment or cables I find in a box is there because it doesn’t work.

So I used me pockethernet (www.pockethernet.com) to test the link, poe and network connectivity and thought I would share.

Having layer 1 test tools is not optional for me since I cant tell you how many issues I resolved that were at layer one.

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Is your Network Security Slowing you Down? (by Jason Nutt)

Is Network Security Slowing you Down?

Measuring the Latency impact Created by Next Gen Security Solutions

As an IT professional, you are well aware of the challenges posed by network latency. Applications like audio and video delivery, bandwidth sensitive mobile applications, cloud computing and storage services are extremely sensitive to network latency.

What you may not realize, however, is the amount of latency created by your Next Generation Intrusion Prevention Systems (NG-IPS) and Next Generation Firewalls (NG-FW). While they are critical to protecting your network, these security tools and others that perform deep packet inspection can increase latency, significantly impacting your overall application performance.

Recently we worked with a large health care services provider trying to figure out why it was taking so long to send MRI data between locations. This was causing significant frustration for patients, doctors and medical staff. Having been aware of Aukua’s nanosecond precision capture and analysis tools, they asked for our help. The company suspected one of more of their NG-IPS devices was causing the delays, but they did not have a way to confirm this. Since these security tools do not treat all packets the same, they were unable to detect or measure the application latency issue with artificial traffic such as ICMP. And since some applications were being adversely delayed and others were not, they could not rely on the NG-IPS vendor’s generic latency specs for various packet sizes. In addition, compliance rules prohibited them from introducing new traffic into their live network.

 

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Using Microsoft’s clip (by Tony Fortunato)

In this video I demonstrate an oldie but a goodie, how to redirect output that normally appears on your screen to a file. I take it a step further and show you how to append to the file as well.

These are great tips if you want to put ping, tracert and other commands into a batch file and schedule some testing after hours.

The only disadvantage to this is that you may end up deleting several files if all you do is put those contents into another file.

In this case you can use Microsoft’s clip command to put your output directly into the clipboard, so all you have to do is paste the contents into your document.

Real straight forward tip that will save you some time when you’re troubleshooting at the command prompt.

 

 

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ProfiTap's Network Superheroes (by Tony Fortunato)

ProfiTap contacted 12 network analysts and had them put their ProfiShark product through its paces. Then the analysts wrote about their specific experiences, feedback and general thoughts.

I read through the pdf's and was intrigued as to what people wrote about and enjoyed hearing from different perspectives.

I personally think the end result was a great mix of articles that i think you would enjoy.

Here's a very brief summary along with the links:

Mike Pennacchi “Measuring Device Latency with the ProfiShark”

  • Mike shows us how to use the SPAN mode of the ProfiShark while determining and comparing the latency introduced by a Microtik configured to use NAT.
  • Very cool to see Mike sharing the methodology behind his testing.
  • youtube.com/watch?v=gMXBhNP9JJs
  • http://www.nps-llc.com

Stuart “Thor” Kendrick In-line Tapping in the Data Center”

  • Stuart takes us through his trials and tribulations while adding another VLAN to an ISILSON cluster.
  • Impressed with the level of detail and photos Stuart provides walking me through ProfiShark Manager and his specific connects.
  • Liked that Stuart used another tool ‘mass-ping’ for his troubleshooting.
  • http://www.skendric.com

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