So, there is an outside possibility that mass tablet deployment may happen here at some point, so I want to start getting my head around it properly.
Things that I'd want to look at:
1. Internet connectivity
2. Onsite proxying
Potentially, it'd be about 600 devices connected around the school. We already have a Ruckus wireless system in place, which we would upgrade and scale up (we have 13 APs across the site on a 1000 series controller). I'd want to at least double that, possibly triple.
We have a 100Mbit internet connection via our LEA which goes via SWGfL. I'd not want to stay with them to be honest. Yes, they work out quite cheap for us at the moment, but they lack flexibility. We also run a TMG proxy onsite, but this is soon going to be no use to us.
So, we would need to replace/scale our net connection, and provide adequate filtering/proxying for it.
How large a connection would people recommend for 600 devices that are more than likely going to nearly always be in use? And for filtering?
One member on here, @Aethon, has just over 1000 iPads in his school (with more to arrive) with a 100Mb connection from the RBC and he's saturating that so they are now moving onwards and upwards to the next connection (cannot remember what size though) but I am sure he can give you some more on his connection and proxying setup, I would expect it to be Smoothwall but stranger things have occurred!
Another thought - VLE. Many of this lot will be using the VLE at the same time I'd imagine, which is Frog. I'm also going to have to find out how well that's going to scale, as I know nothing about it as it was bought whilst I wasn't there!
So, we would need to replace/scale our net connection
If you getting a true 100MB/s then I bet you will be fine. We added 200 extra devices and saw a modest 5-10Mb/s increase on net usage. All our documents and email are on Google apps so there is little in the way of large file transfers.
For filtering a clustered smoothwall would work (does for us), or perhaps lightspeed which is more transparent ( as it works at layer2) but I'm not sure how well that scales.
Judging from the way things are going here, I'd have thought you may need to look at getting something like a 150Mb - 200Mb connection.
As @john mentioned, we're completely flatlining our 100mb connection and looking to move to 1Gb, which is probably a little excessive at the moment but should keep us going for the foreseeable future or at least the next twelve to eighteen months.
As a very rough rule of thumb, I'd consider having around 40\50Mb for every 200 iPads. Of course, the actually traffic they'll generate does heavily depend on what people are doing with them. If you have classes surfing webistes and just being used "normally" then you will be able to get by with a lot less but as soon as you try pushing out apps though and that's when your connection will really start to suffer.
We use a MS TMG for our firewall\filtering and it is set to allow all traffic from the iPads straight through without authentication but after checking for banned websites, etc. The TMG works really nicely for us so you shouldn't be forced to change it. If you want more information about how we have it setup, just let me know.
Besides the wireless infrastructure* I'd have a think about your switches and connections out to your network cabs as you'll need to ensure they can cope with the traffic that's potentially being generated.
(*We use Aerohive and it's got some really nice features that help enormously with iPads, particularly if you are looking at a decent number of devices.)