[K12OSN] Networking a new school for K12LTSP?

[Olivier Mugnier]

Hello

Scuse for my language... but as i am french, I'm sure you will 
understand....

I'm an electrician in France... so I want to give you some technical 
information.

(For the time I take to type this... more information... sorry for 
rebondancy !)

>> 1) Gigabit backbone -- is that just cat6 cabling or does this relate
>> to topology?  And if topology, what kind is the best for LTSP?

1.The main difference between 5 and 6 is that 6 require continued ground 
field protector... You can't leave it even on 1 cm...
So you need specilised socket that take ground far behind.... Cable is the 
same except that the wire are a bit larger....
Be very careful on cat6, normalisation was not complete and not fully 
respected (2-3 year ago... may have change since)

>> 2) What is the difference between solid wires and regular cat 6?  Is
>> there a name for this specification?

2. I think that the difference are in the wire... usually, we but only 1 
wire in copper (*8 for 1 cable) for the wall... While for connection, we but 
many wire (smaller but many) (*8 for 1 cable)
The first one are more difficult to install since the can't turn as well as 
the second... but the first one are better for connection
(sometime, some wire of the small one get off and the over wich was not 
maitain any more go off as well) Secondly, it usually a bit cheaper. Third, 
he doesn't like to be moved all the time... Connections doesn't move if the 
wall doesn't move... There for the first one is usually much more reliable 
than the second.... but
The second is much more easy to turn, and the different wire make it much 
more reliable in time if someone walk on it all the time... (as 1 break is 
not lost of connection) but it is a bit more expensive....
Therefore: The first one in the wall between socket, the second type between 
socket and computer...

>> 3) Is it always the case that it's better to have a room with 4 drops
>> for 4 computers, rather than 1 drop and a switch for the 4 computers
>> to plug into?

3. More wire allow you to easily upgrade to more fastest network...
I mean, usually, once the building is made, adding an extra cable is very 
difficult.... and 1 cable
of cat 5 won't go over 1G (for very short distance), therefore.... even by 
putting a gigabit switch, there will be 1G for all the client....that are 
connect to the hub and client can take as much as 80Mg between them and the 
server...
That the same between no brand giga switch that can go up to 2or3G and 
nammed that can pass-thru 8G and much more....
Remenber that cost is greater for switch than for cable (25€ / switch <=> 
80m of cable in france in cat5) and that power bill will consider that... (I 
don't think that it would be cheaper in consommation without talking of 
Backing up (ondulated))

>> 4) I really like the idea of floor drops and power outlets where the
>> network drops are -- thanks!

4. We have completely recabled our school last year and I already miss some 
power (1 for screen and 1 for computer but printer, scanner, speaker, 
external hard drive, screen projector, phone and much more... We (in france) 
can't use multiple socket for safety of the children...) So I would say now 
3 socket by child computer and 5 for the teacher would be the least...
The same apply for computer socket... We tend to have network printers, Voip 
phone, normal phone (use the same wired)
(and even laptop for some of us) so they put 2 socket for each teacher 
place... 3 should be better...
Floor drop are not bad idears (but cannot be used in france for security), 
but what about 1 or 2 roof socket for projector, wifi access point...

>> 5) We're going to, due to the distances involved, have a primary
>> server room where the network cables terminate, and a secondary room
>> as well.  Is it necessary to connect them via fiber? The distance
>> between them is probably 100 feet.  I'm asking because the hardware to
>> convert fiber <-> copper is rather expensive.  Is it not easier to run
>> several cat6 and somehow bridge them? (technical details fuzzy, but I
>> think you know what I mean! :) )

5. For 100Ft, (30 meter) you can effectively run multiple 1G cat6 connection 
and aggregate them (need branded hardware that support fail/over multiple 
link)

>> 6) For wiring wireless -- this may be something we do in the future?
>> Can I ask them to run cables and power to specific spots in the
>> ceiling and then just leave it as is?

6. For sure, leave them non connected for 30year than use them is you 
want....
Remenber that if you wan't to have a very high speed connection you vill 
have to have more than one cable
or (better I think but depend of the technology evolution) 1 cable for each 
small area...
Wifi is one... phone point can require as well one cable... (6 DECT on a 
wirelless spot wich use 2 wire)

>> 7) Labeling each of the cables with numbers/room location with
>> validation - I got it!
7. I would rather say on socket and on cable and not right at the end but 1m 
before (3ft)

>> 8) How much of an issue are florescent lights?  Our building is filled
>> with them -- should I make a point to mention this?

Yes, absolutely.... The cable can cross florescent lights (avoid) but never 
follow them
The same apply for all magnetic field: Big electric Motor, electric 
tranformateur....
(If  i remenber well, 10 light of this type of ligh can make your cables 
uselless... and that is for Cat5, 1G should be more strict)

The same for high voltage... and even 110V can't be good for your 
transmission...


>>
>>
More remarque

1. Fiber is fast and should be able to go up to 10G for 2fiber.... 6 give 
you 30G... Should be enough...

2. But as much fiber as you can, then as much cable and then if you are 
short in money, but empty pipe can allow you extension (if there not turning 
3 time at 90° on 10 feet with 3 wire inside already and place for only one 
new)
(french specification says that 30% must be free... on power cable and power 
cupboard)
But for ethernet cable, I would rather says 70% free
Let them from the cable road to each mising socket (should be possible to 
but either fiber (specific renforced) or simple cable)
It is more easy to but a new cable in an empty pipe than to add an extra 
cable to a bigger one already fill at 30%... and specially because if it 
break, you have loose the one running....

Remenber that cost is mainly time... and is not double time to but two or 
three at the place of one....
If they are marked correctly you can leave them until you need them...

3. In our school, we have 1 cable for each soket to an computing cupboard...
Then wire from the socket to a switch with half of the socket for now....
And over wire for phone to over socket going to the phone installation
Therefore... ready to move to Voip
Multiple phone wired between main cupboard and building cupboard (4 building 
on 200m / 600ft)


And to finish:
4. 200 student * 80 Mo => 14G
I don't think it worst installing more than 30G.... Technology is too quick 
to change...

5. Are you on different floor or are you on 1 big large place... ? This 
should help to determine topology:
Taking back 100 Cable to one single room is much difficult than 50 to two 
small room on each side,
linked with fiber or copper. The best I think is to have 2 place.... because 
you can but one server on each side
equilibrating charge and reducing risk in case of a fire, an innondation or 
bombing and so on...
More difficult to administrate some will tell... false with Linux, ssh 
deported session of X....
or simply with rsync.... for simple backup...
I hope you won't spend your time behind your server screen anyway...

6. Power security on server room : 2 type of socket and 2 light system 
(protected with 2*2 different circuit)
At least a lock on the door there and on the switch.... not with the 
classroom key... or the building pass....
A server is secure by network access and physical access !

Good luck
>From france




----- Original Message ----- 
From: <cliebow at midmaine.com>
To: "Support list for open source software in schools." <k12osn at redhat.com>
Sent: Wednesday, January 24, 2007 11:17 PM
Subject: Re: [K12OSN] Networking a new school for K12LTSP?


> power over ethernet poe is certainly nice and tidy..for 100 foot run the
> fiberoptic seems a alittle overkill huh..
> if sure like to see a wired connection because sure as can be the computer
> station will be across the room..out in the hall..wherever it seems least
> likely..just a couple ruminations..chuck
>