[Network|Road To 10G] PART I: Not all Ethernet Cables are made equal

Results

Continuity test

HDE Network Cable Tester

After the install of the four new lines, line continuity tests were conducted using cheap network cable tester ($9.99). This type of product do not measure the speed of actual cable. If one is looking for such testing, you need professional grade tester like a one from Fluke ($609). In my case all four lines passed the continuity test.

Speed Test

After the installer left, I have started to test individual runs for exciting new 10Gbps speed. The result are below.

*The numbers here are based on my recollection and may not be fully accurate as I have done so many tests in such short period, and during the time of the test, all I cared were if I could get 10Gbps or not.

The estimated cable length are based on rough physical distance with some padded length. I have not looked at how exactly installer placed cables in attic or wall, so these numbers may be off by a bit, but relative relationship should hold.

Discussion

The result is very peculiar at the least and my initial reaction was a nothing but a disappointment. However, knowing my existing cable with estimated 150ft length achieved 10G up/down, I quickly started to do a self troubleshooting. Followings are steps I have taken.

Once I confirmed 10G is still functional using pre-existed line, I have eliminated laptop, adapter, patch panel, switches, and NAS as a source of the suboptimal speed. So naturally, I hypothesized/blamed newly installed Cat 6 cables.

CAT Cable Interference

There are documented issues of CAT cable getting interference if it travels along/crosses the power-line.

When you run this unshielded cabling in parallel with electrical cables, that magnetic field is disrupted and the communication becomes noisy and garbled. In many cases, transmissions will simply not make it from Point A to Point B. In other cases, transmission rates will slow to a crawl as communications are constantly retried.

10 things you shouldn’t do when running network cable

So my initial fear was indeed this. I have noticed 3 lines that were having under 10G performance were indeed crossing over the some line, presumably TV cable line, just next the network rack. So I have repositioned these cables but it still did not fix the issue.

Another common issue I have read is improper termination of the cable. Fortunately, I have terminated multiple ethernet cables and had own tools for them, so I’ve decided to give a try.

Changes

  • Fixed lines crossing over a cable line
  • Changed termination of Dining and Kitchen

*Of note, Family TV change/improvement may not be a real improvement as my memory is a bit vague if it actually had full 10G from the start, but somehow my email to trueCABLE said otherwise. If it was not at 10G, I think the issue really was coming from something else (that I will talk towards the end of this article).

These changes had give some improvement but still no 10G in 3 out of 4 lines. So I have emailed TrueCable as I started to wonder if I got defective cable, per the installer.

To my surprise, they have been extremely helpful. Unlike typical technical support where we get templated, zero content replies, this was an actual person replying within a couple hours of my email and it actually had technical details. Based on the 100 Mbps link on the Dining line, The technician has pointed out, the issue is unlike to be a cable related but he had suggested a possible improper termination of the cable as a likely source.

What you are describing is not likely not the cable causing the issue. A far more likely explanation are the terminations. 100 Mb/s connectivity typically means there is excessive untwist at the connectors. 

From the email conversation with TrueCABLE Technician

The conductors cannot, according to spec, be over 1/2″ from the last untwist to the point of termination. 

From the email conversation with TrueCABLE Technician

Another tip I have received from them is to use HIGH force setting on punch tool.

I suggest punching them back down like above, but use the HIGH force setting as you are seating 23AWG conductors. The conductors need to be fully and evenly seated into those IDC slots.

From the email conversation with TrueCABLE Technician

These tips were indeed applicable in my case as an installer had his end cable in the wall jack exposing about 1 ft of untwisted cable from its RJ45 keystone on the wall jack side. However, by the time I had emailed the trueCABLE, I had already fixed this except for the use of “HIGH POWER” but still not achieved the 10G speed. So I’ve tried again replacing the termination ends on couple of the lines (Dining room and Kitchen).

Changes

  • Changed termination using HIGH-POWER mode

Now the result on Kitchen is very strange. It reaches to full 10G speed on UP but only 200 Mbps on DOWN. If I switched to 5G port on Netgear i.e. forcing to the 5G connection, I still get 5Gbps up and down.

At this point, I was ready to give up and TrueCABLE has started shipping my new cable. I’ve also contacted my installer and negotiated half price installation/exchange of cables as all terminals are already there.

The following day, I have decided to do a final test and actually take a note for each wall jacks. I might as well replace any cable that are not reaching 10G. My OCD nature actually helped me here. I have tested the line from original install, the longest run, where I thought I had full 10G up and down; however, this time the result was a surprise. I got 10G speed on UP but Down had only 1.2 Gbps. In office, I still had 10G up and down. So this seems similar to the case I was seeing in the kitchen iMac area. Although I had partly started to doubt my memory, I’ve still decided to try eliminating any variable factor even though I didn’t think they would help.

In summary, I have found sneaky issue that was hiding in my network. The part of issue was related to short/medium patch cables, of the same brand Ultra Clarity.

For short and medium cables, I have been using three primary brand products interchangeably.

  1. TrueCABLE Cat 6 Riser Unshielded – self created ($149 for 1000ft)

2. CableMatter Unshielded Cat 6 1 ft x 10 ($15.99)

Cable Matters Cat 6 Cable


3. Ultra Clarity Unshielded Cat 6 1.5 ft x 10 and 3 ft x 10 ($12.99 & $14.99)

Ultra Clarity Cat 6 Cable

Changes

  • Changed short/medium cables from Ultra Clarity to Cable Matter or TrueCable.

Now I got 2 lines getting full 10G speed and the third one technically giving Cat 6 quality; however, this is still underperforming than the other cable I have and I believe its not even meeting a technical specification of Cat 6 cable because Cat 6 cable should be able to support 10G throughput up to 55m (180ft).