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enter image description hereHi I work for a small plant nursery that is split into two parts by a street. The main side of the nursery has the majority of the green houses. There is a main switch in the office and from there we have a series of switches and access points to get internet out to the green houses.

The internet speed stays at a constant 80Mbps until it goes from one green house to another. From there it drops to 8Mbps and stays like that for the rest of the green houses. On the other side of the street, all the green houses are able to maintain the 80Mbps speed which they get from a switch located in the lab. I was wondering what could cause such a big drop from green house to the next.

Edit: I have added a map of the nursery. The red arrow is where the connection speed drops. The stars mean there is a PoE Box or Switch there. All the circles are the access points. Each green house either has grapevines or almond trees.

  • You could improve your question by editing it to add more details. You may find our Question Checklist helpful when editing your question. For example a network diagram would likely help as we have no idea how many devices you are talking about, how far apart they are, etc. But it also may very simply be due to the types of plants in that green house (i.e. water has high absorption for WiFi frequencies, so plants with higher water content may negatively impact signal strength/performance), – YLearn Jun 6 at 19:55
  • Thank you for the tips! – Miguel Guerrero Jun 6 at 20:25
  • What kind of switches are they? Could it be that some are plugged into a 10M port? – Ron Trunk Jun 6 at 23:35
  • Most of our switches are the Netgear ProSAFE GS105E. – Miguel Guerrero Jun 7 at 15:20
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You're not very clear on how the access points are connected. If it's wireless (bridged) ignore this.

Assuming a wired Ethernet connection and chained WAPs, there's obviously something wrong with one of the connections. Either one of the WAP ports is set to 10 Mbit/s (most likely) or the according cable is damaged (possible) or the link has a duplex mismatch (less likely). Check the ports' status in the WAPs whether they read what you expect (e.g. 100 Mbit/s full duplex). If possible, also check for error counters like collisions, runts, giants, FCS errors. If all ports show the right status inspect the cable for damage or test with another, temporary cable.

Also, make sure you don't exceed the maximum link length of 100 m - this requires a solid-core cable for at least 90 m of the link and stranded cable for at most 10 m. If the stranded portion exceeds 10 m, your reach becomes smaller down to perhaps 40-50 m all stranded, depending on the cable quality.

It's also possible that the cable's signal quality has degraded over time. Exposing indoor twisted-pair cable to year-round outside temperatures reduces their life significantly, in extreme to a few years.

Edit

If the link length is an issue: A switch in between starts another segment with 100 m reach on either side (with restrictions applied as above).

However, when running cable outdoors I'd seriously consider a fiber link. There are budget switches or media converters with fiber ports (SFP) and pre-terminated fiber can be had very cheaply as well. Fiber isn't as delicate as twisted-pair cable temperature-wise and allows for several 100 m reach (e.g. 1000BASE-SX runs up to 550 m over OM2; the only slightly more expensive 1000BASE-LX covers 10 km). Just make sure you don't mechanically damage the fiber or undercut its minimal bend radius (30-50 mm).

  • Sorry you are right I did not provide enough information. All the access points are connected through Ethernet cables. I believe that the connection from that one AP to the next is a very long Ethernet cable that might surpass the 100m mark. If I added a switch in between the two points would that help it out if that really is the problem? I'll also check to see if it's damage. Our maintenance team buys rolls of cable and they connect the RJ45s to the cable. I've only been here 6 months, but I'm pretty sure all the cables and APS have been up for at least 5 years. – Miguel Guerrero Jun 7 at 15:19
  • @MiguelGuerrero RJ45 should never surpass 100 meters. As a rule of thumb, it should be a maximum length of 90 meters, making room for additional patch cables in both ends. – user56700 Jun 7 at 15:26
  • @MiguelGuerrero I'm adding those details to my answer. – Zac67 Jun 7 at 15:28
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    @user56700 You're correct, but that's not a rule of thumb but the definition. – Zac67 Jun 7 at 15:38
  • @Zac67 Thank you for all the help and information! I'll talk to the maintenance crew and my boss about this. I know my boss isn't very fond of our WiFi infrastructure, but it's the one the owners decided to implement. – Miguel Guerrero Jun 7 at 16:24

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