rack related issues

Mon Apr 15 15:26:43 PDT 2002

> Dean Kao wrote:
> >    In terms of the rack, can people with install experience give me
> >    some advice?  Anything would be great.

Heather Stern wrote:
>  I've limited experience in *installing* rack rather
>  than just using them but I should warn you that there
>  is more than one "standard"  size and the
>  difference has bitten people buying parts to rackmount.

Some comments on rack sizes and mounting...

The two sizes I typically see are called "19 inch" and "23 inch".
These refer to horizontal spacing between the rails. A "19 inch"
rack is about 17 3/4 inches between the two rails (According to
a quick check with my ruler). Most equipment (such as routers, etc.)
are setup for 19". There are adapters available to let you use
19" equipment in 23" racks. You sometimes need 23" to fit wide
equipment, like Sun Ultra60's laying on their side or E400s on
shelves. The colo's I have looked at have 23" racks inside the
cabinets, but my sample is small.

There is also equipment and shelves setup for 4 rails (front and
back) with about 24" between the front and back, although the
depth varies. They may be free standing, on wheels, or bolted down.

Another rack type uses two rails (sometimes called
relay-racks by Telecom folks) that actually have the back
holes about 6" behind the front ones on a piece of "channel"
aluminum. They bolt to the floor for stability. They may
need "ladder rack" or "cable tray" from the top to a wall to
help with stability.

The equipment you are mounting may have it's rackmount "ears" near
or at the front of the equipment, or it may be at the center
for balance in a relay-rack.

cheers
-joe
Joe Yetter