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Home > Archive > CCDA/CCDP > December 2002 > wiring closet location query
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wiring closet location query
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| Hi,
Just wondering if anybody has an idea about a design query I have.
Even though UTP 5e can go 90M from a HCC to a workstation outlet, when choosing a location for the closet Cisco recommends selecting a location from which whose furthest terminal will be 50M. So basically you are meant to use a compass from potential closets with a radius of 50 M.
Any ideas as to why it is 50 rather than 90M?
( I would imagine curves in the cable could be a factor but 40M seems like a big margin).
Lozza. | |
| dbowen 2002-12-02, 9:11 pm |
| Did you find that Cisco spec on the Cisco website? If so, can you post the link?
I'm just as curious as you are...I always treated Cat5e just like Cat5 (just minding not to crease, stretch, twist, etc.). | |
| Lozza 2002-12-03, 12:02 am |
| Ran a query "choosing a wiring closet" using go.com and got this response:
http://www.wflinn.com/networking/ci...co_Sem1_Ch8.ppt
You will notice in section 8.2.2.3 they make the reference to using a 50M radius when selecting a location for a closet - so I don't think the issue is directly related to whether the cable is cat5 or cat5e.
If you have any ideas as to why they choose to use a radius of 50M rather than 90M you'd certainly help clear it up for me.
cheers,
Lozza | |
| csy71 2002-12-11, 12:59 am |
| quote:
Originally posted by Lozza
Hi,
Just wondering if anybody has an idea about a design query I have.
Even though UTP 5e can go 90M from a HCC to a workstation outlet, when choosing a location for the closet Cisco recommends selecting a location from which whose furthest terminal will be 50M. So basically you are meant to use a compass from potential closets with a radius of 50 M.
Any ideas as to why it is 50 rather than 90M?
( I would imagine curves in the cable could be a factor but 40M seems like a big margin).
Lozza.
Hi Lozza,
So that your end to end distance will no be more than 100m. Infact this is a guide line for 10baseT setup for cat5 cabling in the EIA/TIA spec.
cheers!
csyeo | |
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| Thanks for the reply csyeo.
I suppose then that that means that they assume a un-powered hub will be used. This would mean the hub has no repeater capability and then yep, the 50M stipulation means an end to end distance of 100M will be achieved.
Lozza | |
| chodan 2002-12-27, 8:41 pm |
| While ideal this is not always practical.
Especially in a large building.
My advice is have a one or more fiber plants on every floor with more fiber strands than you think you will use in this century.
BTW you will still run out of fiber strands in a few years.  | |
| depamo 2002-12-27, 9:56 pm |
| The Cisco recommendation is to give you 'elbow room' in your wiring closet. If you go check out a full setup closet, sometimes you have some long runs to get to the switch from the patch panel and keep it neat so that is distance and a connection that adds to your overall length. So say you drop a 100m drop to the patch, you drop in to the patch that has a 10m length to the switch? or worse, 10m to a hub with another 10m to the switch (don't ever say you won't use these when you get an extra 20 people on a floor and your 6.5K is maxed!)
This falls into the 1/3 2/3 rule (well, math is a little off but you get the idea). Planning is never how something ends up so you always give youself room for the unexpected. So from their experience, that is the best 'planning' distance, your needs might be different on availability, space, numbers of users.
Actually I have had full duplex lines go much further then the 100m maximum. You plan ahead of time, you do what works!! |
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