Sep 1, 2008 12:00 PM, By James Careless

Virtual private networks, long a staple of business communications, are finding a place in public safety

Virtual private networks, or VPNs, provide the security of private networks without the cost by using encryption to disguise data through its transmission via a public network, including the Internet. It's a two-fold process: Each IP packet is encrypted, then “wrapped” in another IP packet to disguise it further. At the receiving end, the packet is “unwrapped” — first it is extracted from the incoming packet, then it is decrypted. The process creates a so-called VPN tunnel, which prevents an intruder from seeing the data stream.

The VPN concept appeals to public-safety agencies for many reasons. It is secure, it provides instant interoperability on a network-to-network level between connected agencies, and it allows its users to transport information — voice, video or data — over the Internet, as well as over cellular, land mobile radio, satellite and Wi-Fi networks.

That's not all: VPNs also make it easy for multiple agencies to share the same network space without getting in each other's way. “You don't want the police data traffic to be interfered with,” said Brooks Gianakos, systems engineer for New England Communications Systems, a Motorola dealer in Windsor, Conn. “It is important to have each agency's data segregated from each other.”

Another benefit of VPNs is that they can extend an agency's coverage area to encompass the entire globe. “In the past, public-safety traffic was carried over dedicated T-1 lines, which took time and money to set up to extend coverage,” said Sean Fitzpatrick, manager of network engineering for Tyco Electronics M/A-COM.

“With a VPN, you can easily reach anywhere via the Internet or other public connections,” he said. “Say the chief is out of state on business — if a major fire breaks out, he can connect directly to the incident commander via a VPN, which connects his computer to the department's radio system.”

Of course, in instances where the data is being carried solely over private public-safety networks, VPNs are not required. In the same vein, it is possible to transport encrypted data over a public network securely without a VPN, as long as the encryption is sufficiently robust to deter unauthorized hacking. But the advantage of using a VPN is that it offers a secure tunnel to send data from point to point in the public domain.

And there may not be many drawbacks. “There is some signal [delay] using a VPN, but at a rate of just 3 to 5 milliseconds, it isn't an issue for data or even voice traffic,” Fitzpatrick said.

However, there is one caveat: A VPN does not replace an agency's existing radio system. Rather, it connects to that system, encoding its voice and data communications into IP packets that can be transported to other agencies and approved users.

Want to use this article? Click here for options!
© 2009 Penton Media, Inc.