Subscriber Discussion

Any Thoughts On This Mystery Network Issue At A Mini Storage?

UI
Undisclosed Integrator #1
Feb 14, 2017

Have a mini storage client with cameras on 3 separate buildings each with DVR connected by direct burial cat5e.  One run is pushing the limit length wise, right at 100 meters.  Worked fine for a while  but DVR3 (at the end of the long run) went off line.  thought the cable was damaged, but turns out it's fine.  Here's what's weird.  DVR will flat out not show up at switch in building 2,  However laptop plugged into the cable works great, and sees the other DVR's.  Conversely, if I take laptop up to switch at building 2 it will not see DVR3. No ping, etc. But if I plug direct burial cable directly into laptop, it sees it fine.  I'm at a total loss as to what to do. Have even added a switch at DVR3 location, thinking it might boost the signal a tad. DVR3 was initially just direct connected to buried cable. That seemed to help for a while.  Also replaced the switch at dvr2 but no change.

 

See the enclosed crude drawing.

layout

 

 

UD
Undisclosed Distributor #2
Feb 14, 2017

As you approach the limitations of networking, whether cable distances, bandwidth limitations, etc, you will run into all kinds of strange problems.  Just a theory, but the laptop may be working because it has a better written device driver than the DVR.  My first step with a problem like this would be to find an Ethernet signal repeater to install for the long run.  If the problem persists after that then you may actually have a damaged cable.  Hope this helps give you a few ideas.

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Ethan Ace
Feb 14, 2017

Have you run a cable test on the link? At least to check wiremap, if nothing else. I've seen some cables mysteriously work when plugged into a laptop, but not a switch, and it's turned out to be a shoddy pin or loose wire in the termination.

Also, is there only a switch at DVR2? Nothing near DVR1 or DVR3? I'm just trying to figure out the topology.

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UI
Undisclosed Integrator #1
Feb 14, 2017

I've run a test on a simple tester and get 1-1 2-2 3-3 4-4 5-5 6-6 7-7 8-8, so yeah it's good.

On the topology, The internet router is in the front building and DVR1 is plugged into it.  The switch in building 2 is just a 5 port gbit switch at DVR2 that connects it to the Router in the front building and also receives the buried cable from DVR3.  

 

DVR1 and 2 connect fine.  The switch does not light up when DVR3 is plugged in.  But, as I said, a laptop plugged into the buried cable will see the DVR on SADP and ping it.  

UI
Undisclosed Integrator #3
Feb 14, 2017

Just something to check, make sure you don't have an IP address conflict.

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UI
Undisclosed Integrator #1
Feb 14, 2017

confirmed, no ip conflict.  It doesn't even light up the switch when plugged in.

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Jon Dillabaugh
Feb 14, 2017
Pro Focus LLC

You will find that different NICs will have different levels of ability to connect at the fringe of the network standards. I would assume the NIC in the laptop is of higher quality than in the DVR, hence it is able to operate up to the standard, where the DVR NIC is no longer able.

Another theory, maybe the NIC in the DVR has been "burnt out" over time and can no longer push the boundaries? I would physically walk the DVR3 to the switch and plug it in with a shorter patch cable to see if it is indeed the wire distance that is to blame.

If it turns out the cable distance is your issue, consider a pair of PtP wireless radios to replace the long span. It would set you back less than $200 for the pair.

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UI
Undisclosed Integrator #1
Feb 14, 2017

Ironically, Jon, that is what we had initially (wireless).  We lost one of the stations in a thunderstorm, and when the customer found out it was wireless, he demanded it be hardwired.  So we trenched and buried.  Worked fine for a while and then quit.  I'm beginning to suspect the DVR's NIC being "strong enough".  This little piddly job is about to drive me nuts.  Of course it's 60 miles from our office.

UI
Undisclosed Integrator #4
Feb 15, 2017

He's right.

 

Combination of weak nic and long distance.

 

Who is the manufacturer of dvrs?

 

Test the network capacity not the individual pins.

 

Midspan or poe powered in line booster.

 

 

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Joseph Parker
Feb 14, 2017

If the cable comes out of the ground and runs through the building I'd try a midspan.  

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DW
David Westberry
Feb 14, 2017
IPVMU Certified

I would put a certifier on that cable. I am pretty sure you can check pin continuity and have a successful test yet still not be able to reliably pass network traffic.

 

For a less expensive certifier Real World Certifier by Byte brothers/Triplett is around $600 and offers a bunch of nice features. We pull it out on these types problems.

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AS
Ashley Schofield
Feb 15, 2017

I have recently tested a cable that showed pins 1-8 were good and married up, but when i ran the cable length test, pair 2 was only 5m long, where as the other pairs were 50m...

As David says, get a better cable tester and prove the cable... might be expensive, but at least you wont be wasting man hours chasing your tail

 

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DP
Donald Peters
Feb 15, 2017
IPVMU Certified

I agree with the other posters that pair continuity verification does not provide adequate testing. The maximum cable length should never exceed 300' which allows for 2 x 14' patch cables under the standard. Regardless, the cable in question really needs to be certified.  You can rent a certification tester if necessary but basic units can be purchased for less than $3k.  It may prove to be money well invested down the line.  Just my 2 cents. 

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Mark Jones
Feb 15, 2017

We had a similar situation;  At the very edge of rated transmission distance.  We concluded the cable had gotten stretched, re-ran it and it worked fine.  More than likely you have a cable issue of some sort and I agree, I would try the mid-spans.  Cheaper than replacing your direct burial.  Good Luck.

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UE
Undisclosed End User #5
Feb 15, 2017

First do a test of DVR3 by eliminating the long cable run. Just move DVR3 next to the switch to allow a simple patch cable to be used as was mentioned earlier. You could also move one of the other DVRs to the location of DVR3 to see if they work.

I would ultimately replace the copper with fiber for building to building connections. Fiber is much cheaper than it used to be and you can even purchase pre-terminated cables to make it simpler.

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JB
Jason Brown
Feb 20, 2017

+1 for Fiber. It's cheap, reliable, and the best surge protection you can get.

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Kevin Bennett
Feb 27, 2017

I concur on the fiber alternative.  Cable costs for fiber are reasonable, media converters are not prohibitively expensive, and no need to worry about lightning suppression.

UI
Undisclosed Integrator #6
Feb 15, 2017

check to make sure you removed the PoE injector from the former WAP. It could be hidden somewhere if you re-used any part of the existing cabling.  

Also, make sure you used an outdoor rated cable and put lightening protection on it.  WHAT lightening?? its in the ground,,, but it will give you a ground point and your laptop being non-grounded could have a different potential than the NVR if its grounded, and the DVR 3 location could be grounded/bonded/ or otherwise electrically separated. Try floating the ground at different sides. 

Fiber! best bet between buildings. 

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JH
Jay Hobdy
Feb 16, 2017
IPVMU Certified

Its late and I think I read this right...

 

How about putting a switch at DVR 3? That would basically give you a new NIC...

 

DVR patched to switch, switch to long cable?

 

Or network extender

 

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UM
Undisclosed Manufacturer #7
Feb 16, 2017

Came here to say this, wasn't disappointed.

UI
Undisclosed Integrator #1
Feb 20, 2017

I did that and it solved the problem for a while.  Now it's back doing the same thing.  No connection to DVR3 even going through a small switch mounted back there.

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MC
Marty Calhoun
Feb 16, 2017
IPVMU Certified

Put all of the cable in the TRASH bin and buy $88 dollar UBIQUITI antennas and kiss the problem goodbye forever??

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Jeffrey Hinckley
Feb 16, 2017

Direct burial copper for Ethernet is a disaster waiting to happen.  Different ground potentials between these buildings will cause problems, especially during electrical storms (you lost a radio in the lighting storm).  In this case, you were right initially with the wireless solution (it was probably not grounded properly though).  If that was your initial design sold to customer, and he demanded the wired solution, it should have been fiber. (How much to trench and bury?  Paved lot?).

I would not spend time re-running burial cable.  If this is to be the solution you are to work with, contact Ditek about appropriate isolators or surge protection to project the DVR NICs and switches. Hopefully you buried a conduit (and not the cable) which gives you the ability to pull a terminated fiber vs. another network cable.  If you direct buried the cable, without conduit, there is also the possibility of damage that is touching ground/earth or water, which may show up on your tester as ok.

If this is based on analog cameras to DVRs, I would consider encoders at the remote buildings feeding back to the main building.  Educate your customer regarding the reliability and security of wireless. 

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CH
Corbin Hambrick
Feb 20, 2017

We had similar problems with some underground between buildings.  Distance was only about 240'.  We could get ethernet link but would drop out.

We added the following and haven't had a problem since.

 

http://www.veracityglobal.com/products/ethernet-and-poe-devices/longspan.aspx

 

...will do fiber next time and not even give options for copper.

 

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David Johnson
Feb 20, 2017

I think the poor quality of the NIC in the DVR's is likely the cause.  Had a very similar issue and solved it with the veracity kit.  It's not cheap but it will work.

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U
Undisclosed
Feb 20, 2017

Look at the network stats on the working laptop and on the non-working DVR (if it has network stats).  Check for gigabit vs. 100 megabit or half/full duplex or other subtle cable differences.  Sounds like the cable is half-working and perhaps the laptop is more capable of switching gig/100/full/half.  Try something else on the cable (like a spare camera) 

jw
jim warner
Feb 21, 2017

Twisted pair ethernet is designed by the IEEE to be plug-and-play technology. Large margins are built into the specification to account for less sensitive receivers and weaker transmitters. The parametric margins are needed so that parts can be manufactured by what is essentially a printing process and still have characteristics that guarantee the system will work. A side effect of this is that if you got "lucky" and the silicon gods were closer to the center of parameter target envelope, links that are outside the guaranteed specs will work anyway. 

If you observe a situation where one NIC works and another one fails, it is tempting to embrace the simple explanation that one of them is bad. But it might be that the link exceeds allocated margins for e.g. cable length and your selection of NICs is sampling different parts of the permitted Ethernet interface parameter envelope.

The number of screwy things that can happen if your link length crawls out and touches the margins is very large. So, for example, you might find a link that works fine when it is cold but fails on a warm day. The IEEE specs should guarantee that a system within specs will work. Specs cannot guarantee that out-of-spec systems will fail. 

jim warner, UC santa cruz

UI
Undisclosed Integrator #1
Feb 23, 2017

Unintentional crazy update:  I'm ordering a few boosters to address this issue, and while waiting for the equipment to arrive, I just received a text message from the end user that DVR3 has mysteriously come back on line this morning!.  It's been down for over 2 weeks with no human intervention.

 

Go figure.

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UI
Undisclosed Integrator #4
Feb 23, 2017

temperature changed. Youre out of spec so things like that will have an impact.

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MC
Marty Calhoun
Feb 23, 2017
IPVMU Certified

Put all of the cable in the TRASH bin and buy $88 dollar UBIQUITI antennas and kiss the problem goodbye forever??

 

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Jon Dillabaugh
Feb 23, 2017
Pro Focus LLC

Marty, I would normally agree, but that was what he originally had there. The client didn't like the wireless and made him install the copper. 

If the client doesn't like wireless and the copper is too long, out of spec, they should simply pull some fiber and call it a day. 

If the client won't pay for the fiber, tell him it's either pay for fiber or back to the wireless we go. 

MC
Marty Calhoun
Feb 23, 2017
IPVMU Certified

I kind of agree, poor salesmanship (or industry knowledge) really, someone should have enlightened the customer on how wireless OR fiber will save his ass from lightning damages and hassles like he is facing now. On top of that if you have 1/2 competent technicians you can install wireless for less than the cost of the cable....

and if the customer does not agree move on to the next sale and save yourself alot of hassle and pass the problem site on to your competitor?

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UI
Undisclosed Integrator #1
Feb 23, 2017

Marty, respectfully, I've likely installed more Ubiquiti wireless video links than you have, so I'm very aware of that option.  There's a little back story to this install.  The original install goes back to 2012 with an analog SD system  The building where DVR2 is didn't exist back then.  The back  building had no available power.  We trenched for low voltage from DVR1 back to the back building and installed 3-4 SD analog cameras and ran power and video back up to the DVR in building 1.  Had issues from time to time with those cameras going out, likely attributed to voltage drop.  We switched power to 24 VAC and but an AC/DC converter at the back building and that seemed to help.  

 

Then customer added building 2 about a year ago, and we advised customer that now was good time to fix this issue at building 3.  The plan was to add dedicated DVR to back building and connect back to front with data cable.  Customer was to provide power to back building and allow us a trench when they trenched for power.  Well they didn't notify us timely and the trench got covered before we could get down there.  We therefore put up the UBNT links and moved on.  Didn't get into it with the customer. He's a friend and I'm a customer of his on another deal.  That was until a storm took out one of the ethernet ports on the UBNT at the back building. (Mini storages are like giant lightning rods) I told the customer what happened and he tersely texted me that he wanted it hard wired.  So we rented a walk behind gas powered cable trencher, hauled it down there only to find out it wouldn't crank when we got there.  I was super pissed and just ready to get this over with, so I went to the only local Ace Hardware in this little piss ant town and purchased a rail road pick ax and we hand trenched it.  Got it done in about 3 hours and it worked fine.  Then it didn't and then it did and then it didn't.  

 

It's just been a fiasco.

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UE
Undisclosed End User #8
Feb 23, 2017

Check MDIX, Duplex, Speed - the switch could also be in blocked mode after some errors - so shutdown the port and take it up again.

You could try to set the speed/duplex in static (no auto detect), and also turn off MDIX in the switch..

Since the laptop working, I'm sure there is something like this.

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MS
Mark Sauer
Feb 27, 2017

Good day,

you can order multimode fiber cables any length pre-terminated so no equipment is needed. If you do this, you might order 2 cables, one for spare.  Many switches have sfp slots in them. Purchasing 2 multimode sfp gig modules for as little as 20. each and matched to the fiber for probably 60. is pretty easy to do. As stated above, isolating electrical issues from the remote switches is a good idea, and fiber is very reliable over time. Time is money, how many service call times does it take to cost a lot? I have also had issues like this, one time it was the ethernet connector that had a burned terminal (lightning I think). Now everything has a UPS battery backup mainly for line voltage protection and "line noise" and high or low voltage protection.

MM
Matthew Moyer
Feb 27, 2017

It is possibly the cable. We just (last week) had bought pre made cat 6 jumpers 50ft long to do a job. Some of the wires worked and others would not even show a link light. Cable pin tester showed good no issue. We too a spool of cat 6 laid out on floor, did connectors on each end and it worked perfect. I took one of the jumpers and put it on a fluke wire tester we have for wire runs. Turns out cable is good for continuity, but it is only good for 10mb not 100mb. Cable is only good for phone line use and no good for networking at all. I never knew there was a difference in cat 6 cables before that. So it would be possible that the cable "tests" good with a simple continuity test, but actually not be capable to run the bandwidth you need for  all the video.

U
Undisclosed
Feb 27, 2017

"cable test" in the networking world means you hooked up devices at each end that push ethernet frames through the wire in the planned operational configuration.  In other words hook up two devices, push some data through it (60 FPS camera video on screen with MPEG to a laptop, for example) and then check the computer's link statistics.  Make sure there are zero errors (or get someone to clarify why not.)

Buzzing the cables is about as useful as licking the ends of the cable looking for flavor differences between H.264 video and FTP traffic.  The right Fluke tester should have helped with this (meaning the painfully expensive unit you likely don't keep in the back of every service truck.)

 

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