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TimFlag for United States of America

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How to resolve network connectivity with DSL line

I have a network connection issue and I don't really know how to go about fixing it. The issue is we have a remote site that is in a customer building. In the building we have a storeroom which we store products for the customer when they need them. I have a workstation in the storeroom that is connected to an internet connection which creates a SonicWall Site to Site VPN tunnel. The Internet connection is a 1.5mb DSL line which has the workstation and a vending machine attached to it.

The problem I am having is that the workstation has really bad network connectivity and loses connection to the SonicWall router often and is really slow. I have other clients that are on a 1.5mb connection but it is a T1 line instead of a DSL line and there are 4 people who connect to our network the same way but do not have the same problem probably because they are on a T1 line.

The client connection that is having issues is connected to the SonicWall via an ethernet cable which is 406 feet long and has POE switches on each end. I told the customer that they cable was too long so their solution to boosting the cable signal was to place the POE switches on both ends to boost the signal but I don't think that will work. The SonicWall has GB ports on it which is connected the GB port on the POE switch but when the signal reaches the end POE switch the signal is degraded to 10mb instead of 1GB. I am to assume that is due to cable length but I have some clients in the building that have a similar length maybe, not as long but they don't experience this type of drop off. Additionally the client at the remote site has slow logon time and their connection to the SonicWall drops often. Again I assume it is the cable length but I want to make sure.

I want to bring in a new line that is high speed but if this is a line issue and not a bandwidth issue a new internet connection will not help since it is a line issue instead of a bandwidth issue.

How can I test/resolve this issue in order to fix this issue?
NetworkingVPN* WANSonicWall

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Rob Williams
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Soulja
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I would lean towards a line length issue. Ethernet is usually about 300 or so feet limit. Definitely not a bandwidth issue as your dsl is only 1.5Mbps.  Is  it possible to put a switch in the middle of the run? Is fiber an option for your equipment?
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Rob Williams
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Yes ethernet is limited to 328', exactly.  Any longer and you immediately start having network issues, specifically dropped packets due to timing issue.  Soulja's suggestion of a switch in the middle is a good, easy option.

Also make sure the cable is properly terminated.  Poor punch downs, removing too much of the jacket, and untwisting the wires will all result in reduced performance.
POE stands for Power over Ethernet, it is not a repeater nor an extender. you need a switch or a hub somewhere near the center OR use another cabling method i.e. fiber,  Or powerline ethernet and shorter cables.  Both outlets have to be on the same phase of the electrical connection
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noci

PoE does NOT boost the signal, it only can provide power to the endpoint opposite of the switch nothing else.
You need some ethernet switch in the middle.   Check the counters on the network interface for errors.
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CompProbSolv
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The likely problem is that, as you determined, the cable is too long.  100 meters (about 300') is the spec.  You'd want to put a switch in the middle such that neither end is more than 300'.  You could also change to a fiber connection as that allows longer lengths, but that's not easy or inexpensive.

The T1/DSL issue doesn't really matter.  If the devices can't get a reliable connection to their firewall, what the firewall connects to is irrelevant.
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Dr. Klahn

If the cable in question is older than Cat5, you might want to replace it in any case.  If so, take the opportunity to pull fiber at the same time.

The above comments are exactly right; four hundred feet is about twice too long for reliable operation.

Ethernet over powerline is fine for some homes but I would not trust it in a commercial or industrial environment where there are transformers serving different parts of the building.  It's like carrier current AM; everybody has to be on the same phase (biphase leakage can't be relied on), on the same transformer, and within a couple hundred feet.
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Rob Williams
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>>"you need a switch or a hub"

I am sure David was using "hub" as a general term, but true hubs we used before switches will not work as they do not recreate and send the packet.  I only mention it in case you have an old one hanging around.
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Soulja
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@Rob

Actually a hub would work as well. We know hubs are just multiport repeaters. They're main function back in the day was to extend cable lengths.
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noci

Actually: A hub may work as well depending on port settings if you have a managed switch. (Speed & Duplex).
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Benjamin Van Ditmars
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Tim
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ASKER

Thanks for all your advice. You all answered similar to what I told the customer but wanted to have some validation.
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Rob Williams
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No suggesting at all I deserve points but based on your accepted answer I don't think you believe the cable is too long. This is not a phone line and 328' is not a random number, and includes patch cords.  Bring in any company with a Fluke or HP cable certification meter (About $8,000 unit) and have them test the line. It will fail.  Before I did IT support my job for 4 years was troubleshooting cabling infrastructures. It has to do with the length of time the smallest packet takes to reach the far end of the cable.  Too long, and you have lost packets, collisions, and re-transmits.  UDP may work, but TCP will not.
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Soulja
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@Rob

I agree, I  would like Tim to explain what the accepted solution state that wasn't already stated.
Because everybody is hang up at the cable. but just start at the firewall/router and see if it works there. can also be a bad DSL terminal, or a shaper issue. always start at the begin and work from that point
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Rob Williams
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I agree it can be a combination of 100 things but no where does a cable longer than 328' work with TCP/IP. Why not start there.
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Networking
Networking

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