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BotFodder

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Joined: 01/13/2006 15:23:41
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Ethernet spec is 100 m for CAT 5/5e/6 cable (for all speeds - 10/100/1000 - I'm pretty sure) - that's from a switched port to end point. Hubs aren't usually switched ports and are simply repeaters, and for best results should be considered "mid points" in the 100 m spec.

So anything from a switched port to 300 feet should be okay, save for the quality of the cable. If you're talking unshielded, you might potentially get interference from outside sources (though the nature of twisted pair cabling should minimize that issue).

If there are a lot of kinks in it (I'm not talking turns around corners and such - I mean real kinks) that *might* cause issues.

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v0rTeX

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Joined: 12/19/2004 20:59:52
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... and on that note, if you are using a hub instead of a switch, come to my house so I can smack you in the back of your head. What are people thinking when they buy a hub? Switches are the same price and so much better.

I can back up the statement about kinks in the line. Electrons don't like to flow around sharp corners and square edges. It acts like a resistor (moreso than just a length of copper would) and then the voltage reaching the other end won't always be high enough to be recognized as a '1' instead of a '0'.
Spacey

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It is not necessarily true that anything which does 11g can do 11b. There are two different radios involved here, and some wireless cards (and some access points) have reduced their cost by dropping 11b.

As for 11n and other higher speed 802.11 specs, it is quite true that the specs are not finallized 100%. I happen to work for a wireless networking company, and we actively participate on most, if not all of the various of the 802.11 standards groups. However, at least one vendor, D-Link (who is a customer/OEM partner of ours) has a 108Mbps product. But when dealing with such extensions, realize that they are pulling tricks to achieve this, and one vendor's product may not play well with those of other vendors.

Now, WRT the bandwidth...As fodder says, 11b would suffice if we are talking just UT. The reason for this is that in many cases (more on this in a sec), the limitation will not be on your wireless connection, but on your WAN connection through your ISP, on out to the servers. Indeed, I remember talking with Dru about him trying to limit network usage to that of a T1, which would be 1.5Mbps.
As for when the wireless connection will be the limiter...when you have a number of wireless nodes, there will come a time when each node will only get a portion of that bandwidth. Indeed, many advanced APs will provide settings to limit the bandwidth used per client. As for which one I would get...I would get something which supports g if not both, as the cost for the type of equipment you would get for that is not that much more.

(As for wanting to buy from my employer...our equipment is for a much larger deployment, such as for entire office buildings, hospitals, college campuses or even cities like Koln, Germany.)

Oh... BTW...There are other things which you need to think about when dealing with wireless. They include:

- Security. If you plan on doing anything you would not put on a poster outside your house...read up on the subject, read the manuals, and configure your security parameters!!

- RF Propagation. Are you looking at a house with walls made with old mortar&lath, concrete, bricks, metal studs, etc.? Depending on what the walls are made of and the layout of where your AP and computer will be, you may need multiple APs, or even still have to run your wires all the way. Our house uses mortar and lath, and I have an AP in my office even with one just down the hall. The reason is that my office has a blind spot where the signal effectively passes through about 2-3 feet of mortar just because it is glancing down the wall.

- OS support. While this is generally not a problem with windows, if you are running Linux, you will likely find that you have to go through some hurdles to use some of the newer cards, even with the latest release of the distro.

And Fodder...good reply on the whole, but you will find that you can get DSL with well over 6000/768 now with no problems. My NSP is checking the line to see how much over my current 3000/768 I can run on my DSL connection before I upgrade. But even without that upgrade, I can still suck my employer's WAN connection dry (they have two T1's).

BotFodder wrote:

Anything that does 802.11g also does 802.11b (unless configured not to) - the issue is that if anyone using the access point has an old card that doesn't do g, the *everyone* gets stuck using b.

There are card and router combinations that support either the 802.11n (I think it's n) spec (which is not finalized yet, near as I know) or a special 108 Mbps spec, but I have no experience with either.

Honestly, even 802.11b should be able to handle the bandwidth needed for UT2004 - the 11 Mbps it's theoretically capable of is well over the usual 3 Mbps down/384 Kbps up of most cable systems, or the slower speeds of some ASDL. However, if you've got 20 people using the same access point at the same time, you'll notice some slowness in response. It's basically the same principle of using cable with all of your neighbors - you're sharing that signal.

So, I guess the short answer is ... it really doesn't matter too much. It depends on the capabilities and usage of your current wireless access point and router, but if you get a b/g capable card, you should be set. I can't imagine that they're that expensive. 

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Spacey

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Sour_Grape wrote:
CAT5 is really reliable, and faster, up to 25-30 feet. Longer than that and you start getting some packet loss. Some people say you can go up to 100 feet without loss, but that hasn't been my experience. I know some engineers who refuse to go longer than 16 feet without a repeater hub. Of course all these things depend on how reliable your connection needs to be. Similar to buffered and nonbuffered RAM. For solid gaming I wouldn't recommend longer than the 25 feet. Longer than that and you might as well be using a good wireless connection. 


Funny, I have one link though my house which is around 150', due to the wierd routing. I run this link at 100Mbps full duplex and and easily get it to well over the 90% point, at which point, the non-electrical protocol limitations start in. And even with longer runs at my various employers and clients (which included places like CompuServe and Lucent), and over at the radio observatory, I know of links which were right about the 100m limit, and even then, there was no significant packet loss or latency. But at these distances and data rates, I generally start thinking GigE and fiber.


EDIT: As Fodder points out, running unshielded cable can leave you open to some interference, so don't run it past large motors like you find in your fridge or AC compressors, etc., and you should also stay several feet away from neon lights, and such. The electrical characteristics of twisted pair and the ethernet signaling will generally protect you, but why risk problems?? And as for kinks, a good rule of thumb for bends in Cat5/5e is to go no tighter than the outer edge on a CD where possible, and never go tigher than the inner edge of the reflective area. While it may not seem that bad, if you throw a TDR (time domain reflectometer) onto a line with a tight turn, you will start seeing signal reflections off those tight turns, and at the same time, those become points where the twisted pair will be more vulnerable to RFI.

On the hub-switch debate...you do need to think about this a bit (I never go with hubs, unless I want to snoop the traffic on another port for debugging purposes). But complicating this whole issue are some products which are called hubs, but in reality are really just extremely very dumb switches. I bought a 10/100 hub a few years ago from Linksys (who I will not buy from now), only to find out that it was in reality a switch. I spent several hours one day trying to figure out why I was not seeing the packets I was looking for, until I noticed that I was only seeing broadcast packets and those headed for the host on that port.

And vortex...it is not resistance, but rather the change in impedence (complex part), as you are changing both the capacitance and inductance (both mutual and self) of the pair. The discontinuity only comes into play when considering the twisted pair as an antenna for RFI purposes. I learned this one from folks who learned from Dr. John Kraus, whose EM and Antennas books are still the standard some 60 years after they were written, as well as from John himself.

*BEL*_e (spacey), BEL Clan General -- You Frag em, I'll Slag em!
LA -- *BEL*_e (level 283 - Extreme AM), LW -- *BEL*_o (level 26) MM - ?? ( *BEL*_Rolaids ?? *BEL*DrWho??, Engineer... *BEL*BS_E_E [BSEE '89, Ohio U] (level 22)

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v0rTeX

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Joined: 12/19/2004 20:59:52
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Spacey wrote:

And vortex...it is not resistance, but rather the change in impedence (complex part), as you are changing both the capacitance and inductance (both mutual and self) of the pair. 


Given how few people in a crowd normally understand electronics and communications in that depth, I didn't see a need to confuse anyone.

Renius


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Joined: 06/16/2005 12:00:11
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So I finally figured out what I am going to do to connect my computer to the server of all serves THE "disastrous consequences". My roommates said that they didn't mind if I drilled a hole in the floor so I'll just connect to the router with a 20 ft cat5. Should work out perfectly.

Thanks every one for all the help. I had no clue what I should do. I should be back soon, so BotFodder you had two weeks to enjoy all my kills but now I want them back.
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BotFodder

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Joined: 01/13/2006 15:23:41
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Bah, between the possibly 7-14 levels I may have lost from the crash and the various computer-related aches my right hand has been suffering, you might have a chance.

I had just maxed out DB too ...

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