Hi everyone,

First of all great forum, i've learnt a lot from here thanks.

I'm doing a dissertation for my undergraduate into Wireless technologies, my scenario includes linking 4 hospitals across a city using point to point wireless links like the Motorola PTP5800 which offers a 300Mb connections i have also said that these will be WPA with 63 character pre shared keys and for additional security i will run 256 AES VPN tunnels across them (am i right to think that IPSec consumes around 50% of the bw to maintain the tunnel? and is it relative to the link speed or is the overhead of IPSec fixed?).

At each site there will be a varying number of users and some sites will have video streaming perhaps a live theatre feed to a training room at another site.

I can easily calculate how many Mbps a video stream might require and multiply it by the number of streams, but is there a rule of thumb for the average office/admin worker? Allowing for general usage of network shared drives and web browsing?

As it maybe that only 2 of the four sites have an internet connection, furthermore if i had a Primary domain controller at a main site and remote users had roaming profiles how big would those profiles be if they used mapped drives to store their documents?

So to summarise, what assumptions can be made when trying to determine the required bandwidth for an inter site link?

Thanks in advance
Marc.