384 posts categorized "Test & Measurement" Feed

Keeping Your House In Order (by Tony Fortunato)

I have been involved in a lot of network migration, installation and cleanup projects.

I can appreciate having equipment labeled and areas organized since I am involved in all aspects of the network life cycle: design, Installation and support.

For example, network designers rely on accurate information to figure out how much rack space, power outlets and cables they need for an install.  Installers need the same information to properly install equipment. Then the installers update the installation documentation with any changes and the same applies to the support staff.

One thing I get picky about – almost OCD, is keeping my eyes open for potential issues. Some examples are rerouting or replacing ‘temporary’ cables. I have a laundry list of items I look out for when working anywhere.  I like to think of it as a ‘value’ I add to my services.

Here is a sample of what I look for:

  • Cables that are routed across the front of the equipment
  • Cables that are too short and too long
  • Damaged cabling
  • Extra cables lying around – do they work?
  • Error lights or beeps that are ignored
  • No equipment or rack labels
  • Ethernet cable couplers
  • Inability to close rack doors
  • Power bars ‘daisy chained from one another’
  • Excess dust on equipment and rack ventilation
  • POE injector match port speed
  • Grounding

In most cases, the client agrees with me and we make any suggested changes immediately, when possible. In other cases, the recommendations are noted and scheduled during the next maintenance window.

Sometimes the client doesn’t agree and goes with the odd adage, “if it aint broke, don’t fix it”. Based on my experience, I know that some of the issues are higher priority and its just a matter of time before it becomes an issue.

Last year I showed a client that there was a damaged power and Ethernet cable that should be replaced. He thanked me for pointing it out and I found out later that he did nothing about it. Recently his staff called me for some network performance issues and I was told that manager no longer works there.

I went on site and was surprised that one of the wireless issues traced back to that frayed cable I pointed out a year ago.

Here is a photo of the cables I pointed out and you can determine if it should have been replaced.

IMG_0087 (Large)

 

Picture2
ethernet coupler
Picture2
cable pinched in door

 

 

 

 

 

 

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Why Bother with Ethernet Cabling. (by Tony Fortunato)

I think there is a balance between doing it yourself and calling the professionals. If it’s a straight forward manageable task and you have the correct tools and knowledge, why not.

For example, I wouldn’t climb an 80 foot tower, pull and terminate 120 pairs of Ethernet cabling or try to terminate fibre connectors.

While working onsite I was asked “Why bother?“ or “We’ll get someone else to do that”. Some people feel that some network tasks are too menial or beneath them. I’ve had some network technicians ask why I would bother doing ‘that kind of work’ when you have had various certifications.

There are many answers; I like the variety, I enjoy keeping my skills sharp, and the job gets done quicker. I find I can add more value to a design or install since I have physically done the work as opposed to just reading the materials. The bonus is that when I watch people do incorrect installations, I have more things to look for when troubleshooting problems.

Here’s a simple example: we had to pull and terminate 3 Ethernet cables as part of an install. The technician said “let’s just call the cabling company to do it”. I asked how long that would take and he responded 2 to 3 days. I reminded him that I was only there for the day and added that it would not take us long to pull three cables 20 feet and terminate them ourselves. The cables were a straight run in the cabling trays above our heads.

Just a quick disclaimer; if you have no experience terminating cables, do not practice or learn on your production environment. Fortunately I have been terminating Ethernet cables for over 20 years, so this is a fairly simple process. I went to my vehicle and got a spool of cable, some RJ 45 connectors as well as my crimper. Fortunately, I had assumed that I might need to do this type of work and had prepared myself with the proper supplies and my vehicle.

Flashback; I will never forget working with network consultants at a new build and I was the only one with tools, a hard hat and my government safety certificates, even though everyone was told this is a construction area. The other consultants  were limited when, and where they could work where I had the run of the place.

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Microsoft getmac and MAC Address (by Tony Fortunato)

When troubleshooting it is quite common to get the mac address of the host, server or network equipment for a variety of reasons.

For example, many syslog messages or logs may refer to mac addresses depending on what the error is. If you are working from the switch, you more than likely need to know the mac address if you need to figure out which port the target is for your monitor or span command. And of course if you are using a protocol analyzer, you should always capture with a mac address, when possible.

In this video I review how most people figure out their mac address and how to determine the mac address of another device on the same vlan as you. The issue with this methodology is that in some scenarios you may want to figure out the mac address of a Microsoft device that is on another VLAN.

Using Microsoft’s getmac command allows you to get your mac address as well as a remote system’s mac address. As I mention in the video, this command seems to be using the DCE/RPC protocol, so if you block this protocol on your host, servers, or network you might have an issue with command.

Lastly, you need to know the user name/password on the remote system for this to work remotely.

Hope this helps you with your troubleshooting.

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Four best practices that can ensure application health in an Hybrid IT environment! (by Will Moonen)

In a digitally transformative world where the end-user experience (EuE) is a #1 business priority, understanding how applications perform, especially in hybrid IT environments with multiple security layers, is critical.

Here are four best practices that can ensure application health in these environments.

Graphic 1Best Practice #1: Having the right level of plumbing

Start by knowing if you have the right level of plumbing; that is, ensuring that all relevant packets are captured as they travel across the infrastructure.

Since security policies often take precedence when it comes to managing the entire IT infrastructure, when we look at deployment strategies specific to security appliances, we find that most strategies align these appliances with the application streams. Depending upon the company size and other factors, there may be multiple security appliances, which creates additional security zones (or segments).

This calls for the development of a schematic, conceptual overview addressing all branches/remote offices, datacenter(s), and cloud services, including the application flows.

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Troubleshooting a Spotty/Bad Internet Connection (by Chris Greer)

Recently, I changed my internet service to a new provider. These guys promised some decent bandwidth at a good price.

After getting it installed, nerd-proofed, and monitored, all looked good.

That is until I had a remote training class to teach over WebEx – then the audio issues began. (Of course! Why do these issues always KNOW?!?! Right when you need the connection the most – boom!)

Every 10-15 minutes or so the audio would drop for about 5 seconds. The students could still see my screen, but the audio was clearly having issues. Fortunately, I could call in using my cell and finish up the class with no further problems.

As much as I wanted to blame WebEx, I knew that it was no small coincidence that I had just changed my internet service. Alas, this time it looked like it really was the network! Time to crack out the tools and troubleshoot.

Packet Capture - Wireshark

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