|Lending some insight to an APCO member|
The concept that I tried to convey was fairly simple to say, but difficult to describe: use abstractions to create interoperable networks that are carrier and technology independent.
The Importance of VPNsMost of the audience was aware that VPN (Virtual Private Networks) are useful to link buildings and offices over public networks. Some even had used VPNs to remotely access their office networks. But few realize the value that a VPN presents for interoperability. Public safety operates in a world of many communication technologies. They have:
- Land Mobile Radio - Analog radios for voice communication. This is the walkie talkie or the in car radio that the police use.
- P25 Radio - This is the digital replacement for LMR.
- PSTN - The public telephone network, generally meaning wired
- Cellular - All the flavors of cellular from AMPS to GSM to LTE and WiMAX
- Private Networks - These are wired networks around a city. Could be fiber, copper or microwave
- Public Safety Broadband - This is the 4.9GHz spectrum that was designed to link point to point facilities for redundancy.
- 765Mhz "D Block" - This is the spectrum that is being planned for the National Public Safety Broadband Network using LTE technology.
My premise was that if you had devices that supported one or more (or maybe even all) of these communication technologies with a VPN client that would create a persistent tunnel (encrypted) these links that fails over between all of the available links, you can create a truly reliable, highly interoperable communication network.
The example I gave was this: say you have a smart phone that supports WiFi, Cellular, and P25 technologies. All of the technologies can be connected at the same time to their respective networks. At the back end you have a dispatcher at a PSAP (Public Safety Access Point or E991 call center) with a connection to the internet. On the cell phone you have a VPN client that connects over IP to the PSAP. Sometimes the connection goes over WiFi, sometimes over Cellular and sometimes over P25. As far as the network is concerned the smartphone and the PSAP are on the same "local area network".
On top of this the cell phone runs a VoIP (Voice Over IP) client application. This application acts just like a multi-line phone attached to a PBX. So the user at the remote end can talk to the dispatcher as easily as they use their wired phone. But now the VoIP phone runs over the VPN and can be routed over WiFi, Cellular, or P25 whichever is available. So if the Cellular network fails, the call can stay connected over P25. You might have a brief (1 or 2 second) drop when the fail over occurs, but you will stay connected.
This same VPN technology can be used for data, voice and even video. The VPN doesn't care about the lower technology, as long as IP can be sent.
National Public Safety Broadband Network
|eWRAP multi technology|
Regardless of how a national network rolls out, it is certain that it will support IP and it may still need to be supplemented with other technologies, some including public networks. Using a VPN gives you the ability implement today and then replace the underlying technologies with new technology without having to replace all of your end nodes.
Of course I showed the eWRAP and the microNVR running MVE video as examples of devices that today support multiple communication technologies and VPN.
The next big show is ASIS in Philadelphia. We will have a booth there and can discuss all of this if you stop by.