[K12OSN] RE: Networking a new school for K12LTSP?

[Sam Snow]

>
> Message: 4
> Date: Fri, 26 Jan 2007 11:54:00 -0500
> From: "Joseph Bishay" <joseph.bishay at gmail.com>
> Subject: Re: [K12OSN] Networking a new school for K12LTSP?
> To: "Support list for open source software in schools."
> 	<k12osn at redhat.com>
> Message-ID:
> 	<ba50840701260854p787909c1i7a3b985eb8f6bc10 at mail.gmail.com>
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>
> Hello,
>
> Thanks once again for all the insight! I'm going to be going back to
> the building committee with much of this in mind.
>
> I'm hoping this isn't a very silly question, but I am a bit confused.
>
> I have a question about the MDF and the IDFs -- where all the network
> cabling will be running back to.  Now I know from various setups I've
> seen that often where all these cables terminate there is a rack with
> the hardware that connects to the switches and the patch panel.  In
> our case while we will have a patch panel where the various Cat6
> cables will come in and terminate.  Assuming 4+ drops / room, we'll
> have many, many terminations.  Now, due to the cost of rack-mounted
> equipment, and what we can afford/is donated to us, it is nearly 99%
> sure we won't have rack mounted units for the servers.  Is this not a
> problem if they can't fit into that distribution centre (which seems
> to be not much larger than a big closet)?  Is there a problem to have
> the servers (full size towers) in another room in the building and
> running cables to the distribution centre? Or will there be some sort
> of bottleneck?
>
> My apologies if this is an obvious thing.
>

It sounds like you need to make sure the MDF/IDFs are large enough before 
the building plans are set in stone. It is much easier to provide physical 
security, power, cooling, etc if they are located in an area that was 
designed for them. Also note that many servers have loud fans. You don't 
want them in your office. I know getting a larger room is harder than I 
just made it sounds (I've fought this battle with a new building), but it 
is a worthwhile fight.

For a cheap way to deal with non-rack mount servers look at a Wire Rack 
shelf unit (example at http://www.spacesavers.com/wirshelun.html ). They 
are available at home improvement stores.

Or buy low cost rack mount shelves. I've bought for a reasonable price from 
Gruber and used their "200 LB" shelves for servers: 
http://www.gruber.com/catalog/showcase/34-104400.html . They also sell on 
ebay.

The physical location is not a bottleneck. The servers and switches don't 
know if they are sitting side by side or 50 ft away. The bottleneck would 
come from how the switches and servers are connected. You want (at least) 
a gigabit uplink to the switches from the servers and then a multi-gigabit 
(via trunking/port aggregation) links between the switches if they are 
large. If they are smaller then you are fine with just a single gigabit 
feeding a small switch.

100MB* 8 ports switch (each with one computer hooked up, pulling the full 
100 MB) = 800 MBits/sec. This would be a fine situation to use a single 
gigabit uplink.

100MB*48 port switch (each with one computer hooked up, each pulling only 
50 MB/sec-- half as much traffic as before!) = 2.4GB/sec of data being 
pulled. If the traffic was being pulled from three 1GB capable servers (in 
theory) your bottle neck would be the switch uplink rather than the 
servers.

If you are in a cost crunch, and your general contractor, local inspector 
and everyone else involved will allow it, you might consider using 
volunteer labor to help or entirely run the wires to the rooms. You may 
have parents who are network admins or have this type of experiance. Even 
parents who don't can lend a helping hand when you a pulling a long wire 
run and putting temporary labeling on all the cables. It can be a great 
bonding experaince, a big cost savings, and fun!

If you go this route you will probably want to run a short "training" 
session on wire pulling and have someone on site supervising who know what 
they are doing to make sure things get done correctly. Besides wiring 
whole buildings, I've even installed underground conduit and pulled a 1000 
ft fiber and a 25 pair phone line between two building using all volunteer 
labor except for the backhoe.

Sam