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 Post subject: Network do's and dont's
PostPosted: Sun Apr 20, 2008 12:11 am 
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Location: Up State NY in the USA!!!!
I am starting this thread for those that want to build a network from the ground up or want to improve their existing infrastructure. As I post there will be places that I try to steer you away from wastes of money. Having designed a number of large networks from servers to finished drops and run well over 4,000,000 feet of wire with termination of over 20,000 drops, the IT managers would say I have a fair handle on things.

First thing is the wire. Most of you will not know this but CAT5e is more than enough for a gigabit network. You do not need CAT6 for gigabit speed What is important is that it's quality wire that is tested to 350MHz. This will be far cheaper with a good box of CAT5e generally at about $100-125 dollars per 1000 feet, CAT6 will be upwards of $300.00 per 1000 feet at the time of this writing.

The place to be spending the money is on good gigabit rated RJ45 jacks. Leviton, Siemons, ICC, Amp, etc... all make good jacks. Stay away from Krone as these are total crap. Also don't buy cheap knock offs as they WILL cause problems.

Termination is a place where allot of mistakes are made. It isn't a very hard skill to acquire but it takes experience and must be done properly to assure you get the full performance of the cables and jacks. If you don't know what you are doing you are best to call an expert after you pull the cables to where you want them and have them terminate them for you. It takes about 1 minute to terminate a cable end. The one advantage to having a pro do this is that they will test the terminations to assure that there are no errors.

About pulling, network wire should never run next to power lines and should only cross at a 90 degree angles. There are times when you just have no choice in the matter though. If this is the case be sure and minimize the distance that they run together. Also make sure that there are no tight bends in the wire, That means do not pull it tight around those corners. Remember that the wires in the cable are small and can be delicate, they will break if you pull on them to hard. If a wire becomes stuck or starts to pull hard, go and solve the problem before continuing the pull. Water based pull lube is your friend here, any home depot or lowes will have this stuff.

Yet another option that most do not think of is that of fibre. Believe it or not there is allot of surplus fibre cables, NICs, and Switches out there for cheap. The price premium will be in the range of about 10-25%. For this you get a much more robust connection to your server and switch. In short runs the optical energy coupled into the fibre is more than enough to overcome a bit of dust or slight misalignment of the couplers. Another thing to keep in mind is that a fibre connection is rated up to 550 Meters 850nM multi mode and 10KM to over 80KM for 1310nM single mode. The energy used is more than enough for any run in the home.

WARNING If you do go fibre for some portion of your network do not ever look into a fibre, you WILL suffer eye damage. The energy is in the infra-red range and you can't see it. Always assume that the fibre is energized and emitting. This is especially true in the case of single mode fiber and transceivers. DON'T EVER DO IT!!!!!

The patch cables are another place where money is wasted, ALLOT!!! As long as they are CAT5e rated cables you are good. Again you do not need CAT6 patch cables, save your money.

Switches, gigabit switches are cheap now with 8 port switches going for less than $50.00. The manufacturer is of little importance since for the most part they all use but a hand full of switch chips at their core. This does not apply to switches by companies like HP, Cisco, 3Com, and others in the enterprise class of managed switches/ routers. There are allot of switches on Ebay that are gigabit with one or two fibre ports. These are perfect for your NAS box and a server connection. In addition these switches are generally managed allowing for greater control of your network.

The same is also true of network cards unless you are talking about Intel or older 3Com cards. These are based on Intel chips for the Intel cards and 3Com or Broadcom chips for the 3Com cards. Cards based on the older Realtek chips had performance issues but the newer chips seem to perform just fine. I upgraded a friends home network and NASLite to gigabit using cards based on realtek chips and the performance was limited by the drives. The cards were no name brand at Fry's and cost only $9.99 each. Here is a place that you can really save money. The cards I got for him were using the same Realtek chips as the Netgear and Dlink cards that sold for $25.00 each. There is no difference in the three but name and layout of the chips on the card. Other than that they are all based on the same reference design from Realtek. Unless you are trying to eek out the very last bit of performance from your network these seem to work just fine. Keep in mind the option of fibre for at least the NAS box and the server if you have one.

NICs I have used in the past and had great performance and reliability from.

NetGear GA621 Rev A1 This is a Gigabit SC Fibre card, it has a PCI interface that works in both 64bit and 32bit buses at 33/66MHz. Based on the National Semiconductor DP83820

3Com 3C985SX, the present card in my NASLite box. Has been up for over a year with not one dropped or error packet. Also a 32/64bit and 33/66MHz buses. This card does not support giant packets, I.E. 9K. The largest is 1.5K. It is a solid performer though and supports dual DMA channels for simultaneous reads and writes.

Feel free to interject your thoughts or ask questions and I and others will try to answer.

Mike

I will update this thread as time goes on. Tony and Ralph should also feel free to edit this thread with their thoughts as well.


Last edited by mikeiver1 on Sun Mar 22, 2009 11:52 pm, edited 6 times in total.

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PostPosted: Fri May 09, 2008 2:23 pm 
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Thanks. A post like this is great for do-it-yourselfers like me who enjoy learning but do not work in the networking field and thus cannot rely on personal experience form having set up hundreds of networks. I have a question maybe you can answer. I use my Windows media center PC to connect to my movies stored on NASLite. When I add a movie, I put in the path to the drive and directory containing the move but this can cause problems if I add drives to NASLite as the drive numbering changes. Is it best to set up a mapped drive and then point to the map? I also notice that I can point directly to the NAS drive or point to the drive under 'shares'. Is there any difference in the drive listed under shares?


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PostPosted: Fri May 09, 2008 2:48 pm 
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Joined: Sun Apr 02, 2006 9:05 pm
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Location: Up State NY in the USA!!!!
I started this thread to address the hardware side of networking, This is more of a software related question but I will be more than happy to try and answer as best as I can.

First off my advice would be to use a Hardware RAID card that can expand the volume on the fly. In this way you can add drives for greater storage and not have a shift in the drive numbering. I have one of the LSI 511 cards and it is really easy to setup and the performance seems more than adequate. It has 4 PATA100 ports and will address 8 drives in total. Drives being cheap this is just one way to get into Terabyte storage. Barring going this route I would bet that in the V3 of NL that we may see the ability to set drive numbers and maybe names manually if we want. You guys got that one? :lol:

Now to the question:
As far as I know there is no difference, perhaps Tony or Ralph or one of the others will have a definitive answer for you on this one.

Mike


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PostPosted: Tue Jul 29, 2008 9:47 am 
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Joined: Mon Sep 11, 2006 10:38 am
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Location: Belleville MI
You should of said about solid and stranded Ethernet wire. Solid Ethernet don't cast a lot like stranded Ethernet wire. Because solid Ethernet is ment to run in the wall were it don't move. Stranded Ethernet wire is ment so you can move it like bend it back and forth a lot. Like Wall to computer.

How about keeping the Ethernet wire twisted good when you put on ends. Don't un-twis the wires alot so they are strait before the end. The twisted of them help RF shilding real good.

Did you know you can use Ethernet wire for a very long S/Video with stereo sound. Because they have 4 twisted pair of wires in them or 8 wires. 2 pair for S/Video and the other 2 pair for stereo sound.

You have to make sure the end are wired right too.

Or X-over cable's if going to from same type thing. Like computer to computer or switch to switch. All Gigabit Ethernet auto knows X-over cable or not. Some 10/100 Networks cards do too.

-Raymond Day


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PostPosted: Tue Jul 29, 2008 12:15 pm 
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Location: Up State NY in the USA!!!!
Some good info that Raymond but you have a couple of technical problems that need pointing out.

"You should of said about solid and stranded Ethernet wire. Solid Ethernet don't cast a lot like stranded Ethernet wire. Because solid Ethernet is meant to run in the wall were it don't move. Stranded Ethernet wire is meant so you can move it like bend it back and forth a lot. Like Wall to computer."

Solid info there and correct. Since you point it out the differences between the wire for structured cabling (solid wire) and patch cabling (stranded wire) I will also point out that there is also a difference in the RJ45 cable ends one uses. The cable ends for the stranded plug has the IDC pins in a row where the plug for the for the solid wire has them staggered. The reliability of patches made with solid wire as opposed to stranded is what I would call fair at best. My advice is that you buy good patches with molded strain relief and anti snag covers. You will thank me the first time you pull the cables through a mass of other cables and the retainer clip doesn't get caught. Oh, and the reliability is much better too!

"How about keeping the Ethernet wire twisted good when you put on ends. Don't un-twis the wires alot so they are strait before the end. The twisted of them help RF shielding real good."

The spec calls for that twist to be maintained to with in .25" of the termination for a CAT5e rating and .125" for a CAT6 rating if memory serves. I will also add that you want to try not to over twist or under twist that wire pair at the termination points. As far as RF shielding, CAT5 doesn't generally come in shielded form. The vast majority of what we and other structured cabling installation companies pull is called UTP or Unshielded Twisted Pair. The noise protection comes from the fact that the signal is carried on a differential pair and any common mode signal is nulled out at the receiving end by the transformer and the filter/s. this is the same scheme used in the likes of the PCIe, DVI and HDMI interfaces as well as SATA, SAS, LVD SCSI, AES/EBU, and ballanced mic and line audio to name just just a few. Installing shielded CAT5 a bit of overkill for the most part and the termination cost will kill a structured cabling budget real fast.

"Did you know you can use Ethernet wire for a very long S/Video with stereo sound. Because they have 4 twisted pair of wires in them or 8 wires. 2 pair for S/Video and the other 2 pair for stereo sound."

Kinda true. You have a bit of a miss on the technical side here that needs to be cleared up The impedance of the wires and the interface standard impedance need to be matched for the end result to be good. The standard impedance of CAT5 network cable is 100 Ohms and is balanced. Composite Video, S-video, and Component video are all a standard nominal impedance of 75 Ohms unbalanced. In the case of audio the standard impedance is generally 600 Ohms for pro equipment (Thank the phone company) and around 10K Ohms for consumer stuff. There needs to be a matching transformer or line driver between the source and the wire and again between the wire and the load or end point. This is critical to maintain the best signal to noise ratio possible and in the case of analog video prevent ghosting. It is also very important to point out, since we are being technical here, that all of the analog video and audio mentioned above are unbalanced signals and that the transformer or line driver converts the unbalanced signal to a balanced signal giving us a good bit more noise rejection than we would get from simple shielding. There are native balanced audio interfaces, these are generally professional or high end audiophile in nature, XLR and TRS being just two of many interfaces in use by them. This maximizes the noise rejection of the run. I will also point out that there are converters for just about any other interface standard you can think of to be run over CAT5 cabling. Some are very expensive, then again doing this right generally is. HDMI is a popular interface and allot of home theater installs will have the equipment far from the projector or monitor and require a long run to get the signal to and from. CAT5 is a cheap way to make this happen.

"You have to make sure the end are wired right too.

Or X-over cable's if going to from same type thing. Like computer to computer or switch to switch. All Gigabit Ethernet auto knows X-over cable or not. Some 10/100 Networks cards do too."


What you refer to is MDI/MDIX in the physical interface standard of Ethernet. To be frank, this really will not effect many now days since for some time the chipsets used in even the cheapest switches sensed and switched the TX and RX pairs if needed. Some older switches may not do this and so when going from switch to switch you may need to use a cross over cable to get things to work. A note here, the minimum length of a cable between nodes in Ethernet is 1 Meter. Do not use a 1/3 Meter cable as you may have issues with dropped packets and errors. I see very few switches or NICs that do not do MDI/MDIx. Also don't forget that for a cable to be a cross over for both 100BaseT and 1000BaseT that all four pairs need to switch since Gigabit uses all four pairs, 100BaseT only uses the Orange and Green pairs.

Thanks for the input Raymond.

Mike


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PostPosted: Wed Jul 30, 2008 9:34 pm 
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The S/video does work super good. I made my own cords. Bought a 10 foot S/Video with Stereo on it. Cut it in half and put female Ethernet ends on them. I used a 100 foot Ethernet cable then and hook it up to a video camera out side on some baby birds and to the PC. I got sound and video of them and it looks super good. The video camera has S/Video out.

So it was about 110 foot long and doing video that looked just as good as a 3 foot long S/Video cable.

I have a cable like that running in the wall to from are living room TV to a bed room. It's about 80 foot long. Does Super Sound and Video.

Sound like you know a lot about Ethernet. That's good. But I guess you never tested out S/Video with them. Sound works good too ether send to get like I did with the video camera.

-Raymond Day


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PostPosted: Thu Jul 31, 2008 12:08 pm 
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"The S/video does work super good. I made my own cords. Bought a 10 foot S/Video with Stereo on it. Cut it in half and put female Ethernet ends on them. I used a 100 foot Ethernet cable then and hook it up to a video camera out side on some baby birds and to the PC. I got sound and video of them and it looks super good. The video camera has S/Video out."

What I said still stands, there is a minor impedance miss match on the video side. In your case the cameras line driver is well designed to compensate for this and it worked for you. There are many times that this will be the case, in structured cabling we don't have the luxury of taking that chance though. By "Structured" I mean all low voltage cabling and not just network.

"Sound like you know a lot about Ethernet. That's good. But I guess you never tested out S/Video with them. Sound works good too ether send to get like I did with the video camera."

In fact I have done this for composite, Svideo, and Component on numerous occasions. In some of them it worked OK, in others the results were less than stellar. Allot of the net result depends on the equipment at the ends. Just because the result is good in your case does not mean that it will work for the next guy, or me for the matter. If you are looking for the best results, use a Balun at each end.

"So it was about 110 foot long and doing video that looked just as good as a 3 foot long S/Video cable."

I would be willing to bet that if you were to do a blind A/B between the cables that you would notice "smear" in the image on the longer cable. It really doesn't matter though since it worked fine for you and you are satisfied with the end result.

There are always short cuts that can be taken but just because they can be doesn't mean that you necessary should. To be frank, doing things right in the arena of structured cabling can get quite expensive. Not so much in the specific area of networking, fibre excluded, but when you get to high performance video and audio. In my case I always think about the next guy to come in after me, is he going to look at my work and think, "What a F#@kin slap dick!" or "This guy really knew what the hell he was doing!"

Thanks again for your input Raymond,

Mike

Quality work is a thing of beauty, that which isn't quality is fodder for ridicule. I see allot of fodder.


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