Data Center Wiring Standards

Sat Sep 9 15:08:14 UTC 2006

> Rick Kunkel <kunkel at w-link.net> writes:
> 
> > Can anyone tell me the standard way to deal with patch panels, racks, and
> > switches in a data center used for colocation?
> 
> Network Cabling Handbook by Chris Clark is a bit dated (5 years old)
> but probably should be on your bookshelf anyway, particularly since it
> is ridiculously cheap used/new on Amazon (I got my copy a couple of
> years ago after a friend tipped me off that they were on sale for
> $5.99 on clearance at Micro Center).  It's mostly geared to the
> enterprise but it does have a chapter on doing communication rooms
> which is probably a good starting point.  ISBN 0-07-213233-7
> 
> Also, no substitute for visiting your competition and taking a survey
> of how others, particularly larger datacenters,  are doing it.  :)

Having seen so many different things over the years, I don't actually think
there's any one particular right way to do it.

Is the data center carrier neutral?  If so, that tends to lead to solutions
where circuits need to be run point-to-point (whether physically or
virtually).

Are customers expected to be requiring large amounts of bandwidth?  If not,
aggregation based solutions may make more sense (such as putting a switch in
each rack).

What's the smallest and largest customer footprint?  If you're going to sell
5 racks to a customer, in a shared cage with doors and side panels, and the
customer needs multiple gigE connections internally, do you want to try to
solve that problem as part of your site strategy, or do you figure it out on
a case by case basis?

Possible solutions are varied.

For a colo where they'll be buying your bandwidth, and nobody's using
gigabits of it, for example, there's an excellent manageability argument
to be made for running a (single, pair of) gig uplink to each cabinet and
having a 24- or 48-port 1U switch in the cabinet.  You will have a minimal
amount of wiring, which makes problem resolution easier, and you can even 
do vlan stuff to allow customers with equipment in different cabinets to 
have virtual private segments.

I've seen providers that put a 24-port patch panel in each cab and then
ran it back to a central switching point, which is arguably more useful
but eats up a lot of wiring, and you have a fundamental problem in that
some cabs may be populated with colo'ed 1U's (so you hit the wall or have
to add another panel) and others have a single customer with a bunch of
goofy equipment, and they just want a link to their own router/firewall,
so you only use 1/24th the cable.

Facilities like Equinix probably don't have a lot of realistic options
other than what they already do, given the sheer complexity of it all.

... JG
-- 
Joe Greco - sol.net Network Services - Milwaukee, WI - http://www.sol.net
"We call it the 'one bite at the apple' rule. Give me one chance [and] then I
won't contact you again." - Direct Marketing Ass'n position on e-mail spam(CNN)
With 24 million small businesses in the US alone, that's way too many apples.