DECT Multicell support

[mrtrev]

Yes we would also like a solution where multiple base units can work in unison.

I think the topology would work something like:
- Set up a "Super Base" that handles all SIP registrations for up to 100 accounts. This unit does not need to talk to the phones directly.
- Each "Base" unit is configured to communicate with the Super Base via Ethernet.
- Each Handset is able to connect to any Base that it's near. The Base will notify the Super Base that the phone is connected to it so that incoming calls can be routed to the correct Base.
- If a Handset roams to another Base, the Super Base will gracefully handle the hand off so any active phone calls are not dropped.

With this configuration each Base could support similar ratings as current (ie. 5 handsets / 4 calls) but the system overall would be able to handle a much larger number of handsets and every user can seamlessly roam to any area with coverage.

Each SIP account is configured once and each handset is configured once. The Super Base manages all of the associations, and the Base units are essentially remote radio antennas for it.