we have a slightly different issue – and are using a client / server model to connect a regional office to a data centre (over 3g)
Our bandwidth drops when we try and use Netbalancer – to bond / aggregate – should we be using Net balancer at both ends?
In your situation I’d look into setting up multiple VPNs, one on each link, between your regional office and the data center. And then use bonding, not net balancing, to create one virtual link between the office and the data center. I haven’t used bonding on Zeroshell but in a previous life I used it between a Linux based storage device and some servers. If I recall correctly there are a number of bonding options including some designed for load balancing.