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Question

Adding Switch in Network Wreaks Havoc!!!

Apr 20, 2018 9:19AM PDT

I have an Amcrest 16 channel network video recorder (NVR). Model number NV2116. I have connected it to 16 cameras. The recorder is in an office that has only one network cable running back to the main network switch. I need to add a switch in the office where the NVR resides in order to connect a PC to the network.

Everything works fine when connected directly to the main switch.

See links:

Network schematic with no switch

Network graph with no switch

The issue is that when I connect the NVR to the network through a switch I get erratic network reception by the NVR.

See links:

Network Schematic With Switch

Network graph with switch in place


This causes stuttering and dropped frames in the recordings. When I connect the NVR directly to the main switch, everything runs smoothly.

I have tried three different network switches, all with the same result of erratic network reception by the NVR. I have no clue why adding the switch would make any difference.

Network switches I have tried are all 10/100. I have not tried a GB switch yet but I am thinking this will not matter.

Can anyone offer a solution short of running a dedicated network cable back to the main switch?

Discussion is locked

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Clarification Request
We did encounter a few switches that would drop packets.
Apr 20, 2018 10:09AM PDT

These were some discount models (not by Cisco, Netgear, HP or names) so it was costly to find out where the issue was. Imagine spending 10s of thousand in engineering over your buyer picking up a deal? We were not happy about this.

Given the high number of devices the switch will have to be commercial in nature with a big table for MAC addresses and such. The consumer grade models may buckle under this load.

The GB switch even if it's consumer stands a better chance of working here because most have bigger buffers and can process more packets per second. That said, your system may have been on the verge/edge of being in trouble with all those hops already and the new switch is the straw that broke the camel's back.

HOWEVER you have way too many switches and may be breaking an old rule about number of switches from one end to another. https://serverfault.com/questions/724607/how-many-network-switches-can-i-daisy-chain-together kicks this around with the usual 7 hops and spanning tree limitations and so on.

Finally the things that happen in switches mean it may take time for all the switches to learn the MAC addresses. But I don't think that's in play here yet.

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Answer
Wireless access point was the culprit
Apr 20, 2018 11:29AM PDT

I discover what was causing the issue.  I had a wireless router configured as an access point plugged into the switch that I was adding. I never tried unplugging the access point from the switch (don't I feel stupid).  Anyway, after unplugging the access point from the additional switch, the NVR works fine with the additional switch.  No idea why the access point would cause the issue but I can find another place for the access point.

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Did I miss that in your diagram?
Apr 20, 2018 11:32AM PDT

From memory I only found the added switch. I wonder if this is as I noted above where a switch's table is finally topped out.