View Full Version : Ethernet switch won't work although connecting a computer does
rickkaye
Jul 14, 2012, 11:11 PM
I am trying to wire Internet access to the workshop in my garage. The wireless in my house does not reach there. Fortunately, the previous owner ran wire from the room with my router out to the garage and separately ran a wire from the garage to the workshop. But, he left those two wires unterminated.
I had never done any wiring before but I decided to try to do this myself. So, I read up on the process and bought the necessary tools. I put RJ-45 connectors on both ends of the wire from the router to the garage. Then I put an RJ-45 on the garage end of the wire to the workshop and attached the workshop end to an RJ-45 outlet.
I then plugged into the router, attached the two wires in the garage with a straight through coupler and plugged a computer into the outlet in the workshop. To my surprise, it all worked. Why was I surprised? In addition to this being the first time I had done any wiring work, I had "cheated" when attaching the RJ-45 connectors. When I stripped the wires, I found that the twisted pairs were not just twisted (as they were in the patch cable I practiced on) but they were in a single strand of insulation (I'm not sure exactly how to describe this but there were four strands of plastic, each with two wires packaged inside.) I didn't know how to separate the two wires that were packaged together so I wired the connectors with all four color - color/white pairs next to each other. I know that's not the standard. But from what I read, as long as I wired both ends of the cable the same way, everything should work. And in fact, it did.
But then I wanted to connect two devices in the workshop to the Internet. So, I pulled out a switch that I had lying around and it did not work. I could not connect through it. I tried using different wires but it still did not work. I hooked up a WAP to the outlet and that worked fine. I could connect multiple devices wirelessly to the WAP. But one of the devices I want to connect is not wireless. I figured maybe the switch was bad, so I bought a new one and that did not work either. I took the switches into the house and tried them and they worked fine. Basically, I can connect any single device to the Internet in the workshop. But if I connect a switch it's no go even if only one device is plugged into the switch.
I don't think my non-standard wiring of the connectors should make a difference but I included it in case. Does anyone know why a connection would work fine for a single device but not work with a switch?
Scleros
Jul 16, 2012, 08:54 AM
See Media Dependent Interface (http://en.wikipedia.org/wiki/Medium_Dependent_Interface). What switches do you have? Switch to switch links generally need either auto MDI-X port capability on both switches, using a crossover cable, or using a selectable uplink port on one of the switches with cabling wired straight through. Yet, since the switches worked connected to the router in the house with the same patch cables as used in the garage (?), also double check the wiring order.
I also suggest terminating the cabling at both ends in a box to punchdown jacks (example: CAT6 RJ45 Keystone Jack (http://www.cablestogo.com/product.asp?cat_id=3552&sku=29311)) using a punchdown tool instead of using RJ45 plugs and couplers. Using stranded RJ45 plugs with solid wiring or the opposite can be problematic long term if plug style is not considered.
rickkaye
Jul 16, 2012, 02:32 PM
Thanks for the response, Scleros. The switch I bought is a Netgear FS-105. It is the successor to the device pictured on the MDIX page you linked to. The manual does not use the term MDIX but it says it has "Auto Uplink" and configures each port "depending on whether you’re connecting to a device (computer, server, or printer) or networking equipment (hub, switch, or router)". I was wondering if my non-standard wiring could have messed with this feature, but I don't see how.
The RJ-45 outlet that I'm using in the workshop did use a punchdown connector to connect to the cable in the wall. I could switch to punchdown connectors in the room with the router and the garage. But, remember the connection works fine when I plug the WAP into the wall in the workshop. It is only when I interpose the switch that I have a problem. Is it possible that problems using RJ-45 plugs and couplers would show up after the switch is introduced even though the connection was working flawlessly before that?
Scleros
Jul 17, 2012, 09:13 AM
Do you have or can make a crossover patch cable to try for kicks?
Does the router auto-uplink too? If you can take the switch into the garage and plug it into the router with the same patch cable as used in the workshop and get link (connection), then there is an issue with the wiring somewhere.
The stranded/solid plug thing is that using the wrong type for the cable can result in the connection degrading over time. That shouldn't be an issue now.
How far is the workshop from the garage?
rickkaye
Jul 17, 2012, 03:20 PM
The router has only one MDIX port and that is used to connect to the cable modem. So, here's what I tried:
1 - I took the WAP into the wire closet and connected it directly to the router. That worked.
2 - I connected the switch directly to the router and the WAP to the switch. That worked.
3 - I went to the garage and disconnected the wire that runs to the wire closet/router from the wire that runs to the workshop. I connected the wire from the wire closet/router directly to the WAP. That worked.
4 - Still in the garage, I connected the wire from the wire closet/router to the switch. And I connected the switch to the WAP. That did NOT work. On the switch, I could see that the port with the wire to the router did not light up and blink the way it does for an active connection. Of course, I also tried it and while I could connect to the modem, I had no Internet connection.
So, the problem lies in the wire from the wire closet to the garage. But, it only shows up when it connects to the switch. When I connect that wire to the WAP, it works fine.
The straight line distance from the wire closet to the garage is 100-125 feet. But the cable is buried so I do not know how long it is.
Any thoughts on what could cause this?
I could go out and get a crossover cable but I'm not sure what to do with it?
Scleros
Jul 17, 2012, 06:24 PM
I could go out and get a crossover cable but I'm not sure what to do with it?
The crossover cable could be used as the patch cable from the switch to the wiring in the garage just to see if it worked if perhaps the auto-uplink wasn't negotiating properly.
Any thoughts on what could cause this?
If the terminations or cable are "iffy" the switch's implementation may just be fussier than the WAP's about linking.
The distance should be within the 100 meter limit for 100BASE-TX Ethernet (http://en.wikipedia.org/wiki/Fast_Ethernet) and not an issue. Does the underground cable jacket say CAT5, CAT5E, or CAT6, etc?
Is the cable in conduit? Pulling new might be quicker than troubleshooting the existing.
If you have enough cable slack, redo your terminations to punchdown jacks paying attention to pair order and amount of untwist. Then, connect a computer to the garage end and check that it not only links but fully works by transferring a large file from the house to the garage via the underground cable and see what throughput rate you get or if there are lots of errored packets. The command netstat -es from a command prompt in Windows will display errors and statistics. The network interface adapter in the computer may also have diagnostic tools on its property page in the device manager.
Or, if there is a local network installer in the area, they may be willing to come out with a certification or other tester to verify the cable and eliminate any trial and error troubleshooting for you.
rickkaye
Jul 21, 2012, 03:16 PM
I bought a crossover cable and tried it. It did not work.
I doubt the connection is iffy since I get excellent throughput through the WAP. Pinging outside sites does not show any dropped packets.
I bought a cable tester when I bought the tools for making cables. The cable shows up as fine on the tester.
Basically:
1) The wire works for every device except the switch.
2) The switch works on other wires.
3) The only difference for that wire is that I used a non-standard (but consistent on both ends) wiring pattern when terminating it.
Is there any reason why the non-standard wiring would confuse the switch?
Scleros
Jul 21, 2012, 08:07 PM
Is there any reason why the non-standard wiring would confuse the switch?
The switch doesn't care what the insulation color of the wires are, however I re-read your original post. 10/100 Fast Ethernet uses the pair on pins 1 and 2 and the pair on 3 and 6. Gigabit Ethernet uses all four pairs if you decide to upgrade later. If you did not separate the pair normally connected to pins 3 and 6 and instead wired each pair in sequence across the plug, the signals on 3 and 6 will be split and carried on one conductor each of two different pairs which would result in the loss of the benefits of the cable's twist to exclude noise and crosstalk. Depending on how thorough the switch's protocols are it may be detecting this. Question for Netgear.
What tester did you buy? Inexpensive ones may not detect split pairs.
rickkaye
Jul 23, 2012, 11:23 AM
I did buy an inexpensive tester. It sends a signal on each wire, one wire at a time in order, pin1, pin2, etc. At the other end, a light flashes as the signal is received. So, if wired "correctly", at the receiving end you see pin1 flash, followed by pin2, followed by pin3, etc. It does not detect split pairs.
Until I read your post, I didn't know split pairs were a problem. While trying to resolve this, I called Netgear a few days ago. They were spectacularly unhelpful. The guy I spoke with basically said since there are no configuration options for a switch, there was nothing he could do to help me. He did make one offhand comment which I dismissed at the time but in light of your explanation might have made sense. He said I might want to return the switch and buy a cheaper one. He said sometimes the cheaper ones are less fussy about the connection.
From what I'm reading now about split pairs, it is possible that the WAP would work while the switch would not in the presence of split pairs.
I guess I need to figure out how to terminate the wires according to the standard so I don't have any split pairs. Thanks.