Hey, guys.
I have a customer that wants a backhaul link mounted to the top of a grain elevator with the Cat5 run terminating in his equipment room about 700 feet away. Since Canopy helpdesk refuses to recommend any kind of solution, I am turning to you.
I need some kind of simple piece of gear that can be put into the middle of this 700-foot run to get his backhaul signal back to his equipment room. Any suggestions? Do I just go with a powered hub or do I need something more complex?
Anyone had to deal with this? If so, are there any brands of equipment you’d recommend?
Thanks! 
Just stick a switch in the middle. It’ll split it into two 350 ft runs. Supposedly you can only run cat5e 320 feet, but I’ve run it farther and it’s been working flawlessly. You’re seriously not going to notice much latency on your pings. On the run I’m talking about we were still within 1-2 milisecond averages.
I hope this helps. As long as you have the switch in a weathertight box, or in doors, it’ll work fine.
Bortnem1 wrote: I have a customer that wants a backhaul link mounted to the top of a grain elevator with the Cat5 run terminating in his equipment room about 700 feet away. Since Canopy helpdesk refuses to recommend any kind of solution, I am turning to you.
320 feet (100m) is the furthest you should use CAT5 . And it's dicey... we put our equipment 7 meters down on our 100m tower because of this (stored the CMMs inside).
You're going to have to use powered repeaters at best, every 100m. That will add some (probably negligable) latency and complexity. There's no possible way you will get 150m out of a cable run - at least two repeaters are going to be needed for this job, and I'd suggest one every 75m.
Use a repeater if you can, if not then a powered hub with repeating capabilities will do (3Com has some very inexpensive 4-port hubs that do this...)
Do you really need to bring the cable into the equipment room? Is he buying a service from you?
Bortnem1 wrote: Hey, guys.
I have a customer that wants a backhaul link mounted to the top of a grain elevator with the Cat5 run terminating in his equipment room about 700 feet away. Since Canopy helpdesk refuses to recommend any kind of solution, I am turning to you.
I need some kind of simple piece of gear that can be put into the middle of this 700-foot run to get his backhaul signal back to his equipment room. Any suggestions? Do I just go with a powered hub or do I need something more complex?
Anyone had to deal with this? If so, are there any brands of equipment you'd recommend?
Thanks! :D
Install a wireless bridge between the grain elevator and the house?
or
Set up bridges on PoE 250 feet from each end. Thus three hops, [house]-250'-[bridge]-200'-[bridge]-250'-[elevator]?
Personally I'd do the wireless bridge between the house and the elevator.
Just my two.
Excellent! Thanks, everyone. I knew I could count on you.
I’ll probably go with a simple POe switch or hub in an enclosure. The environment is extremely dusty, so I’m going to have to protect it somehow.
One follow-up question: I thought the POe standards for Canopy were a bit different than the “standard” POe switches out there. I seem to recall someone mentioning that in another thread where I asked about re-routing the POe capabilities of our CMM2 with a POe switch.
Does using a standard POe switch or hub work with the Canopy backhauls?
Again, thanks everyone!!
You cannot power Canopy SMs, APs, or BHs from an industry-standard PoE hub, switch, or mid-span injector, without adding a DC-to-DC converter at the Canopy end. IEEE 802.3af power-over-Ethernet uses 48VDC (40VDC min.) on either the unused pairs or as a bias voltage on the signal pairs. Canopy uses 24VDC on the unused pairs only; Canopy’s minimum voltage is, I suspect, 7-10VDC, but I’ve not verified my guess. Using a CMM Micro, which imposes a timing signal on the power, makes this issue moot.
Be careful about the equipment – or at least the terminology – used in a multi-hop, layer-2 Ethernet link. You must use an Ethernet “switch” or “bridge” to connect two maximum-length copper cable segments. If a “hub” or “repeater” is used, then the 100-meter limitation applies to the COMBINED length of the two segments. The restrictions are straightforward for 10mbps Ethernet, but are confusing for 100mbps Fast Ethernet because there are two different types of hubs.
Cat5 cable is limited to 100 meters. Cat5e, Cat6, Cat-whatever, can be used reliably at longer distances for full-duplex Ethernet and Fast Ethernet segments, but I don’t know what lengths are possible. You must, however, be careful to use Cat5e (or better) jacks, plugs, and installation techniques: cable bends, kinks, and crush-points – even plastic tie-wraps – all tend to reduce the electrical separation of the pairs, increasing crosstalk.
The 100-meter limitation is also related to signal delays. A shared Ethernet segment, with or without hubs, must be short enough to avoid undetected packet collisions. Ethernet is CSMA/CD; the “CD” stands for collision detection. The segment must be short enough so that the beginning bit of the shortest possible packet will reach the other end of the segment before the last bit of the same packet is transmitted. Collisions, however, cannot occur in a dedicated Ethernet segment, and every port on an Ethernet switch is one end of a separate, dedicated Ethernet segment.
There are also “Ethernet extenders” available. www.TutSystems.com makes the XL5050, capable of 50mbps of full-duplex bandwidth over 1000 feet of a single pair of telephone wire (sub-Cat3). They also make the XL-4000, capable of 10mbps over 4000 feet of a single pair. I just looked at these units earlier today for another post on this forum and found a problem: they are severely limited in the number of MAC addresses they can “remember” in their bridge table. I’ve emailed Tut Systems and they’re going to test ways around this limitation on Monday. I’ll post the result.
Teknix:
Thank you! This is a lot of great information. I do remember there being problems with the V+ standards between standard POe and Canopy…
I received a response from Tut Systems about their VDSL-based XL-5050 Ethernet extender with a bridge table limitation of 32 MAC entries:
Before the table is full, the unit operates as a self-learning bridge. After the table is full, it operates as a transparent bridge.
The 32-entry limitation will not limit the XL-5050’s use for servicing a Canopy AP cluster serving 1200 customers.
We generally use multimode fiber for long distance runs. This requires power at both ends of the location, however. Many of our installs are in 50+ story buildings, so we end up with cable runs approaching 1000 feet sometimes.
I try to avoid “repeaters” and stuff like that because they essentially become big fuses in the cable run. If you run 10/Full instead of 100/Anything over Cat5e, you can easily reach well beyond the 300 foot range.
I agree with Patrick. The best solution is a Fiber Link.
You can pick up a pair of Ethernet to Multimode Fiber Tranceivers off eBay for less than 200/pair. You will need to terminate the fiber cable or you might be able to find someone who will preterminate it for you.
this will be a much more reliable link, and allow you to expand in the future as needed.