Blame it on the Cable

Anyone who spends a lot of time in their careers installing or fixing layer 1 (Cable, jacks), knows that IT people can be quick to blame the cable for their network connectivity issue.

Network Troubleshooting (or most types of troubleshooting) usually comes down to isolation.   Some folks have a hard time with this concept.  They bounce from one idea to the next hoping to get lucky and find the smoking gun.

When I troubleshoot a suspected cabling issue, I'll usually start with Occam's Razor philosophy - that the simplest explanation is most likely.   For instance, did any event occur prior to the onset of this problem? Lightning storm, remodeling? Furniture rearranging?

Once I've exhausted a little bit of time on that with no success, I'll begin the isolation process.   Or, you could think of it as "process of elimination".

My experience is the actual horizontal cable is usually not the culprit.  Cables in the walls and ceiling usually don't go bad on their own.   That old excuse about rats chewing on the wires?   In 30 years, I don't think I've ever seen that.

But, just to be sure, and appease the IT guy.....

I'll start by testing the cable's continuity by using a cable tester as demonstrated in this video.

If you happen to have a cable certifier (a tool that tests for speed capability of the wire - cat5e, cat6, etc.), then by all means, please use it.   However, usually if a cable passes the continuity test, then if it was a cat5e cable when it was installed, it's probably still a cat5e cable.

If the cable fails, the first place I look is the data jack on the wall.   This is the most likely thing to get damaged - corrosion, bent pins, or pairs breaking off from the keystone insert.

If it's not the wall outlet, you can check the termination in the wiring closet (MDF, IDF), those usually aren't a problem unless someone has been doing some changes on the wiring panel.  

Lastly, at this point, the horizontal span of the cable could be damaged (again, it's rare in my opinion),  looking for the problem could be challenging, but it may be easier and the same amount of time/effort to run a new cable.   Because, if you do find the damaged area, there may not be enough slack in the cable to allow you to terminate a splice - which really isn't' a best practice anyway.

Your Electrical wiring can carry Internet

 Did you know that you can use the power outlets in your home (or small office) for sharing network connections?

That's what this thing does.  It's called a Powerline Adapter.   It plugs into the wall and then there is a network port at the bottom where you connect your network cable from the router (or switch).

These work in pairs (or you can have more than2).  They are usually sold in sets.  Here's a picture of a set I recently reviewed on my Youtube Channel.

These are the HN 2000 Wave 2 Powerline Adapter Kit

The way they work is they're just using the house electrical wiring as a way of sending the signal from one adapter to the other.   You could think of them as a Network Bridge of sorts.  

The big benefit to you is being able to bring Internet (network) connections to places in your home/building that are otherwise hard to reach with wire or WiFi.

They require ZERO PROGRAMMING.  So simple, any non-technical person could install these.

Here are the steps:

1. Unpack

2. Plug one powerline adapter to wall outlet near your router (like less than 20 ft.)

3. Connect Ethernet Network cable from Router port to network port on bottom of Poweline adapter.

4. Plug the other powerline adapter into an wall outlet in some other part of the house, near the computer (or Smart TV, Game console, security cam, WiFi Access Point).

5. Connect Ethernet Network cable from network port on bottom of Poweline adapter to the device needing Internet.

6. Check for green lines on both adapters.

7. Data should now be flowing.  If no green lights on adapters, try different wall outlets.

Here's that video if you want to watch it.

Connecting Android Phone to Router with Ethernet Adapter

 

If you've ever wondered "how could I directly connect my cell phone to my router", well this article is for you.  If reading is not your thing, I also made a video of it at the bottom of this page.

All I did was simply connected this Dell 1gig USB C Network Adapter to my Samsung FE20 Android phone.

Now, I had actually does this before years ago and made a VERY popular video about it, but at that time there was no (easy) way to back feed a router's WAN (internet) port via the Ethernet connection.

However, something changed along the way and I discovered there is now a setting in connections just for tethering via Ethernet.

After that, all I had to do was hook it up to my router's WAN port and I magically had data!   

I also made a video about it HERE.

Wifi, but no internet

Good question on my YouTube channel this morning.

I can see I have a wifi connection, but I can't get to the internet.


Just because you have wifi, doesn't mean you have internet.  Wifi only carries the Local Area Network connection.

  Here's a quick way to tell.
1.  If you have a Windows machine open a CMD prompt (search CMD, then open).   Try the command PING 8.8.8.8.   If you get Replies then you have an internet connection.    If you get request timed-out, then the while you may have a network signal,  but it's not getting an Internet connection.
2. Next check for DNS -  Try the command PING yahoo.com - If you see replies, then you have DNS .   However, if you see something else like "could not resolve" or "requests timed out".  DNS may be the issue.   You'll need to work with a support person to get your DNS straightened out.

Troubleshooting Cisco Aironet 1520

I spent all day working on an Aironet 1520 recently.  Here is my brain dump.

Short of opening the front panel, most of what you need for troubleshooting is located on the bottom (photo above).  In particular are 3 things:  Ethernet port (far left whole), 4 LEDs (next to Ethernet port) and the Reset button which is accessed by removing the Phillips Head screw (far right).

If you do need to connect a console cable, open the front panel and you will see two RJ-45 ports.  The console port is not labeled as such, but it is the black (not chrome) RJ-45 closest to the bottom of the unit.

CAUTION NOTES::
- when the RF1 and RF2 lights are GREEN, try to limit your exposure to the unit by less than 6 ft.

- do not carry the unit by holding on to the Omni directional antennas.  They break easily.

- do not power the AP by using a POE port on the switch or an injector that was not specifically designed to be used with the 1520.  The 1520 does not use the regular POE standard.  Only use the big silver injector that is designed to go with this unit.

My troubleshooting tips:
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- The LEDs on the bottom tell you quite a lot about what is going on.  Ideally you want all four to be green.

- I made a video about the LED boot up sequence which you can find here:

•  LEDs will be hard to see during the daylight unless you are just a couple feet away from them.  Trying to read the LED status from the ground will be tough.  Red is quite a bit easier to see than Green.
•  Troubleshooting will be more convenient if you an take the unit down from it's high mounting location and work on it on the ground.  I decided to set it up on a 4 ft ladder so it wasn't laying on the ground (which would inhibit good reception).

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• Removal of the Ethernet cable is made much easier if you stick a small flat instrument (small flat blade screw driver) in the access hole to depress the locking tab down while you pull out the Ethernet cord.
• Factory reset: while the unit is powered-on, remove the phillips screw from the bottom exterior (it's the only one) and that will give you access to a reset button.  Depressing the reset button for 10 secs and then releasing will factory reset the unit.
• Antennas, be sure you have the proper type antenna for each of the 4 antenna connectors.  Each is labeled.  There are THREE 2.4ghz antennas and ONE 5ghz antennas.
• Do not operate the unit without the 2.4Ghz Antenna connected.
• Check for competing Wifi devices in close proximity. If you are having connection problems (reception issues), you may to discover and eliminate sources of Wifi (other un-authorized Wifi AP's, Personal MIFI devices).  Use a program like Net Stumbler or InSSIDer to help discover theses.
• NO uplink LED:  there is something wrong with the network connection.  Check your cabling.
• If you can't get a connection (as in a mesh peer-to-peer), consider taking the injector and the unit to a location slightly closer to it's nearest peer.  Then, power on the unit and wait 5 mins. Even though you may not have the unit plugged into the network, you should still at least see the unit's mac address appear on the mess network (check the controller software).  This will at least prove the unit is capable of connecting. (maybe there is RF interference at the normal location that is preventing the unit from connecting).
• Check the switch port settings where your 1520's Ethernet connects.  If the switch is a POE, then your inline power setting need to be "off" or "Never" instead of Auto.

Here's a "getting started" guide I got from Cisco that really helped me with the LED stats.

Cisco Aironet Quick Start guide

RJ-45 corrosion

Something to check if you are having network connection issues, shine a flashlight into the RJ45 socket to check for corrosion (or pin damage).  I see this a lot on floor jacks and in restaurants.

Any place where the jack would be exposed to moisture.  Another problem is grime build-up.  This happens a lot in commercial kitchens when oily steam permeates the air and condenses on the pins inside the jack.

Alcatel-Lucent DMXtend 1665

I encountered one of these bad boys while working an assignment for Level 3 the other day.  I can't speak authoritatively on this.  My guess is this is a multi-plexer for multi-tenant services within the building.

In other words, L3 would bring a high-capacity fiber into the building and the use the DMX to split it into individual fiber channels to feed different tenants within the building.