[92184] in North American Network Operators' Group
Re: Data Center Wiring Standards
daemon@ATHENA.MIT.EDU (Mark Foster)
Fri Sep 8 21:25:39 2006
Date: Sat, 9 Sep 2006 13:23:59 +1200 (NZST)
From: Mark Foster <blakjak@blakjak.net>
To: Rick Kunkel <kunkel@w-link.net>
Cc: nanog@merit.edu
In-Reply-To: <Pine.LNX.4.44.0609081724400.24867-100000@samwise.w-link.net>
Errors-To: owner-nanog@merit.edu
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> My thoughts go like this: We put a patch panel in each rack. Each of
> these patch panels is permanently (more or less) wired to a patch panel i=
n
> our main patch cabinet. So, essentially what you've got is a main patch
> cabinet with a patch panel that corresponds to a patch panel in each othe=
r
> cabinet. Making connection is cinchy and only requires 3-6 foot
> off-the-shelf cables.
>
> Does that sound more correct?
>
> I talked to someone else in the office here, and they believe that they'v=
e
> seen it done with a switch in each cabinet, although they couldn't
> remember is there was a patch panel as well. If you're running 802.1q
> trunks between a bunch of switches (no patch-panels needed), I can see
> that working too, I suppose.
>
> Any standards? Best practices? Suggestions? Resources, in the form of
> books, web pages, RFCs, or white papers?
Theres a series of ISO Standard for data cabling but nothing is yet set in=
=20
stone around datacentres. I think the issue of Standards in datacentres=20
was touched on here some time back?
Ok, a quick google later,
TIA-942 Telecommunications Infrastructure Standards for Data Centres=20
covers off a lot of the details. Its pretty new and I don't know if its=20
fully ratified yet?
I quote...
--8<--
Based on existing cabling standards, TIA-942 covers cabling distances,=20
pathways and labeling requirements, but also touches upon site selection,=
=20
demarcation points, building security and electrical considerations. As=20
the first standard to specifically address data centres, TIA-942 is a=20
valuable tool for the proper design, installation and management of data=20
centre cabling.
The standard provides specifications for pathways, spaces and cabling=20
media, recognizing copper cabling, multi-mode and single-mode fiber, and=20
75-ohm coaxial cable. However, much of TIA-942 deals with facility=20
specifications. For each space within a data centre, the standard defines=
=20
equipment planning and placement based on a hierarchical star topology for=
=20
backbone and horizontal cabling. The standard also includes specifications=
=20
for arranging equipment and racks in an alternating pattern to create=20
=EChot=EE and =ECcold=EE aisles, which helps airflow and cooling efficiency=
=2E
To assist in the design of a new data centre and to evaluate the=20
reliability of an existing data centre, TIA-942 incorporates a tier=20
classification, with each tier outlining guidelines for equipment, power,=
=20
cooling and redundant components. These guide-lines are then tied to=20
expectations for the data centre to maintain service without interruption.
--8<--
The source url for the above was=20
http://www.networkcablingmag.ca/index.php?option=3Dcom_content&task=3Dview&=
id=3D432&Itemid=3D2.=20
You may like to see if you can track down a copy of the referenced=20
standard.
From=20my personal POV -
You have a couple of options depending on your switching infrastructure=20
and required cabling density - and bandwidth requirements. One way would=
=20
be to have a decent switch at the top of each cabinet along with a Fibre=20
tie to your core patch / switching cabinet. All devices in that rack feed=
=20
into the local switch, which could be VLAN'd as required to cater for ILO=
=20
or any other IP management requirements. Uplink would be a trunk of=20
1000SX, 1000LX, MultiLink Trunk combinations of same, or perhaps even=20
10Gig Fibre.
The other option would be to preconfigure each rack with a coupla=20
rackunits of fixed copper or fibre ties to a core cabinet and just patch=20
things around as you need to. Useful if you are in a situation where=20
bringing as much as possible direct into your core switch is appropriate,=
=20
and cheaper from a network hardware pov - if not from a structure cabling=
=20
pov.
Good luck. I know what a prick it is to inhereit someone elses shoddy=20
cable work - I find myself accumulating lots of after-hours overtime,=20
involving essentially ripping out everything and putting it all back=20
_tidily_ - and hoping that I don't overlook some un-documented=20
'feature'...
Mark.
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