What's up with my Cat 5?

[matt91]

I have some computer equipment in the basement, and some on the second floor. Each floor feeds into its own gigabit switch, and these two switches are connected by a single Cat 5 (5e, I think, but not positive) cable.

This setup has worked well for at least a year. Computers on one floor seemed to be communicating with others on a different floor at > 100Mbps, although I had never done a true speed test, because things seemed to work well.

About two weeks ago, my MVP that is remote (i.e., different floor) from my Sage Server started to demonstrate some lag when working through the menus. Since upgrading the Java months ago, this MVP was always extremely responsive. I now get a second or two lag after each button push. Once I get a show running, though, it plays fine.

What I have also discovered is that I absolutely cannot transfer a file between computers on different floors. I can still "remote desktop" into my headless server, and although it is a little slower than it had been, it works.

My cabling, it should be noted, is probably pretty cheap and runs largely exterior to the house.

So, any thoughts on what might have gone wrong that prevents some communications (i.e., Windows-based file transfers) but allows others (streaming a MPEG2 to a MVP).

THanks
matt

[GKusnick]

If it's outside the house, it really ought to be Cat5e ("e" = "exterior").

My guess is that your cable has taken some minor damage (a kink or a water leak or something) that causes one or more conductors to intermittently drop out or short, making gigabit connections unreliable. UDP traffic (such as streaming media) is probably more tolerant of such flaky connections than TCP traffic, so that could explain why some apps keep working (with lower throughput) while others fail.

You could test this theory by running a new cable out the window from floor to floor to bypass the existing questionable cable. If performance and reliability improve, it's time to replace the installed cable with something more robust.

[MattHelm]

Originally Posted by GKusnick

If it's outside the house, it really ought to be Cat5e ("e" = "exterior").

Um, the "e" in cat5e stands for "enhanced", not exterior. Most cat5 (or 6 or 3) is NOT rated for outdoor use.

See: http://en.wikipedia.org/wiki/Cat5e

Originally Posted by GKusnick

My guess is that your cable has taken some minor damage ...

I do agree with that.

[GKusnick]

Originally Posted by MattHelm

Um, the "e" in cat5e stands for "enhanced", not exterior. Most cat5 (or 6 or 3) is NOT rated for outdoor use.

You're right; my mistake. I guess I shouldn't believe everything the cable guy says.

[matt91]

Originally Posted by GKusnick

You could test this theory by running a new cable out the window from floor to floor to bypass the existing questionable cable. If performance and reliability improve, it's time to replace the installed cable with something more robust.

I'll just have to wait until the rain/snow/sleet stops, the kids aren't using the system, I don't have a honey-do list...

Is there cabling that *is* rated for outdoor exposure? We may be moving soon, so replacing with similarly cheap Cat 5e might be the way I go (I got a year out of it last time), but if the cost isn't too bad, I might try to do it right this time.

Thanks for the advice.
matt


Edit: Answering my own question: I see that there are lots of outdoor rated cables available (online), I just have to see what the cost is versus non-outdoor rated.

[Mark57]

Originally Posted by GKusnick

You're right; my mistake. I guess I shouldn't believe everything the cable guy says.

It WAS pretty funny though. I needed a good late Friday snicker. (sorry at your expense)

Originally Posted by matt91

I'll just have to wait until the rain/snow/sleet stops, the kids aren't using the system, I don't have a honey-do list...

Is there cabling that *is* rated for outdoor exposure? We may be moving soon, so replacing with similarly cheap Cat 5e might be the way I go (I got a year out of it last time), but if the cost isn't too bad, I might try to do it right this time.

Thanks for the advice.
matt


Edit: Answering my own question: I see that there are lots of outdoor rated cables available (online), I just have to see what the cost is versus non-outdoor rated.

Even with the outdoor rated cables, depending on where they are physically on the house, you might consider some type of cheapo conduit in really exposed areas. Also, make sure you don't have any kinks or real tight bends in the cable. It it's UTP cable, it's solid wire (as opposed to more flexible braided patch cable) and very stiff. If you bend it too sharply it can cause damage inside the wire and effect speed. Also the fasteners you use to mount/hold it to the house can cause the same problems if they crimp the cable.

[malbec]

FWIW ... you might consider switching to wireless N and avoid the rewiring all together. Just a thought, I would probably rewire myself with outdoor grade cables

[geogecko]

I'd probably use regular Cat5e inside of some PVC conduit. Most likely, this would be much cheaper than an outdoor rated cable.

Also, make sure you are using Cat5e, IIRC, e is required for gigabit speeds.

As someone else also mentioned, you could go with WiFi-N, but it's only rated for about 1/4 the speed of a wired gigabit connection, although still pretty speedy.

I plan to upgrade to a DIR-855 when some more reviews are out, and get some of the HD bridges to go with it (they are also dual band, like the 855--dual band that uses both radios at the same time, not just one or the other).

[reidfo]

I've done pro cabling installations for many years now. The other posters are correct, you should have at least Cat 5e for gigabit speeds, and outdoor rated cable won't necessarily solve any problems.

Gigabit may work over Cat5, but it could be unreliable. As for the outdoor cable, it will help protect against moisture intrusion, and may have a stronger outer jacket, but that's it. Run standard Cat5e in a conduit and you'll be fine.

[perf]

But is it really the cabling? If you can not even transfer small files, isn't it more likely to be a problem with the switches? If the cabling is the problem, then the remote desktop protocol and the protocol for the MVPs must be very much more fault tolerant than the protocol used by Windows for copying files. Is that really the case?

/Per

[geogecko]

Actually, it can be the cabling, or anything in between.

In my old house, I wired a couple of rooms to my garage, where I kept a media closet. I used Leviton Structured Wiring solutions, and was using a 5 port LAN card, which was basically just 110 punch downs, with a PCB that converted those to regular Ethernet plugs to jumper over to the switch. I thought the card was rated for gigabit, but it turns out it wasn't. I was having really weird problems, where small files would transfer just fine, but anything larger would say it was going to take tens of hours to transfer (a couple GB file, on a gigabit network?). Other times, it seemed like the network would just disappear, and I'd have to go restart both machines, and reset the switch...so in some cases, it didn't matter what the file size was, but it was more prone to affecting larger files, in my case.

After leaving it that way for probably 6 months, I finally went into the closet, yanked the wires off the punch downs, and installed a regular Cat5e connector, plugged them into the switch, and all problems were fixed.

So a little card that only has maybe 4 inches of PCB traces on it can even affect these signals. Heck, you have to watch how you hook them up to the punch down Ethernet jacks you install in the wall. If you untwist more than half an inch, like they say, performance can be degraded.

So, long story short, it can be any number of things, including the cable.

[src666]

One more thing - any cable that enters the house needs to be grounded. This means using grounding blocks at _both_ ends of your exterior CAT5e, _before_ it enters the house. It's an expensive PITA, but so is replacing all of your network and computer gear the next time lightning strikes in your neighborhood.

[mrwolf]

Originally Posted by geogecko

...so in some cases, it didn't matter what the file size was, but it was more prone to affecting larger files, in my case.

This is similar to the load being put on an analog wire. I have used the ping utility to troubleshoot many T-1's and other connections by adjusting the size of the ping packet. Theorhetically, it should not be this way but I've proven to more than one telephone line tech that theory and reality are two different things.

Originally Posted by geogecko

If you untwist more than half an inch, like they say, performance can be degraded.

Untwisting the pairs more than half an inch should not degrade performance to any detectable level. If it does, there is a bigger and different problem. "Certified" cable runs are rated much higher than what they will carry.

This doesn't mean you can run 100Mbit over barbed wire, though. Cabling should be clean and neatly installed by someone who knows how to use a punch tool. Most of the time, first timers don't get it right.