[c-nsp] cat6 gigE

[Lawrence E. Bakst]

1. Cat-6 is (much) harder to terminate yourself than Cat-5. To get it to work reliably you need to allow for only 1/2 untwist per pair.

2. Good connectors are critical. Load bar often helps. Sentinel makes great stuff. Top of the line. However they don't provide end user support.
http://www.sentinelconn.com/

3. As to what grade cable is "required". That is not the issue. It's all about how much margin you want to have on the various parameters that you need to measure. Sure it is supposed to work with CAT-5E, but there isn't much margin. Cable is relatively cheap. No reason not to overkill and get top of the line cable from Mohawk, Berk_Tek or other top of line cable companies.

4. A good tester is really required otherwise you are just operating blind. A tester is required for GbE.  Fluke DTX-1800 is great and future proof to 10 GbE. It costs $6-7K. Also let's you keep a record of every cable assembly on a PC. If you can't afford a tester you should wither buy pre terminated assemblies from a reputable vendor or have a pro do it.

You need to measure NEXT, PSNEXT, ELFEXT, PSELFEXT, ACR, PSACR, and RL at both the local and remote ends. If you don't understand this stuff either learn it or hire a Pro.

Best,

leb


At 3:15 PM -0800 12/8/06, Shaun wrote:
>We've been upgrading some of our uplinks between our edge switches to dual
>gbit rather than dual 100mbit.  Cat6 was ran but we've been having a few
>problems, right now we've been having a few problems getting them to link
>up.  We crimp the cable, put the module in the 2950G's and plug it in.  No
>link, even with the 3750G set to mdix auto but if i take that same cable and
>plug it into a 10/100 port it links fine.  We've gotten a few 2950's to link
>with out a problem but the last 2 we did have not worked.  Figured it was a
>bad crimp but recrimped it 3 times now..  I dont have a tester so i'm going
>to buy one but i was just wondering if there was somthing special that
>needed to be done with cat6.  Were using the TIA/EIA B wiring scheme.
>
>Any recommendations on a decent priced tester?
>
>~Shaun
>
>
>
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