We found a fascinating network in a school. It needed fixing.
With limited time, controlled budget and limited cabling in place, we needed to find the starting point.
The major choking point for the network was the hub. Although hubs and switches look similar on the outside, inside they are very, very different. They have sockets that you plug cables into and they have flashing lights.
In a hub, every piece of information is copied to every connected device. In a switch the information is copied only to the relevant device (eventually). This is a very, very simplified comparison.
In practice it meant this – if any user asked for a streamed video from Espresso, every device was copied all the information. This resulted in the network being on its knees.
Simply – the hub had to go.
That’s the pinch point solved – now at the other end – which devices generate the highest/most time dependent data. In the curriculum network this was the server and the Espresso server. The data cabinet is a shallow depth one, and an extremely good switch for this situation is a 10/100 with 2 Gigabit ports. Typically the 48 port Gigabit switches are either very deep or very expensive.
The 2 Gigabit ports were earmarked for the 2 servers.
There’s a shortage of network points – one per class
By taking an 80:20 view of life we could see that in each class we urgently needed a clean link for the teacher/white board PC and a clean link for a wireless access point. With one data cable.
This is where cable economisers are so valuable.
These devices work in pairs – one unit at the socket in the wall and one in the data cabinet. 2 devices are linked to the socket in the wall – this links to one socket in the patch panel in the data cabinet. The other economiser links the one patch panel socket to 2 switch sockets.
Here’s how:
In CAT5e cabling only 4 of the 8 wires are used for each connection – economisers make use of the other 4.
These allowed us to remove the switches in the classrooms. This tidied up the work area, reduced power consumption and cleaned the network path.
The economisers are passive devices and simply link wires together. The domestic grade switches had an impact on the network traffic.
The new network looks something like this -
By trialling one decent industrial grade wireless access point, we were able to connect 12 laptops to the Espresso system with no dropped connections.
The school now has the structure in place to allow a fully managed wireless network to be added at a future date.
More importantly, the network can start to become a powerful resource for the school.
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