As plain old telephone service (POTS) continues to fade into obsolescence, alarm dealers are increasingly choosing to send alarm signals via IP-based communications. In this scenario, the alarm technician will connect a cable from the alarm control panel to the customer’s router and transmit the alarm communications over the Internet.
This type of alarm reporting is gaining in popularity and virtually all alarm manufacturers have developed a method of IP communications for their control panels.
Historically, alarm dealers have been concerned with the reliability of IP communications. A typical POTS connection is up and working approximately 99.99 percent of the time. Alarm dealers can increase dependability even further by programming another number from a different carrier in the secondary communication number of the panel’s programming. In this case, if the primary number fails because of a carrier issue, the panel would dial out using the secondary number, which would then dial into the same receiver at the central station.
Border Gateway Protocol Primer
This method of utilizing redundant POTS carriers has been employed for many years. There is an IP equivalent of this methodology being used today, and it is known as Border Gateway Protocol (BGP). To quote Wikipedia, BGP is “the protocol backing the core routing decisions on the Internet. It maintains a table of IP networks or ‘prefixes’ which designate network reachability among autonomous systems.”
BGP’s primary metric is the shortest autonomous system path. That means it selects the best path through the Internet by choosing the route that has to traverse the fewest autonomous systems.
OK, so in layman’s terms: most people know POTS communicators transmit via a telephone number dialed by a digital dialer. In the IP world, the communicator transmits via an IP address. The IP address is a string of numbers that assigns a residence for the communicating device much like a phone number resides at a certain address.
In a typical scenario, an IP address is assigned to a single carrier, and because few if any businesses or residences have multiple Internet service providers (ISPs), alarm dealers have been forced to send IP signals utilizing the customer’s single ISP to the central station.
In BGP, the IP address is published with two different routes over two different ISPs, generally by the central station. In this case, once the IP address is programmed in the control panel at a customer’s site, it will hunt for the best path between the two providers. Once it establishes the best path, it will use that path to communicate to the central station from that day forward. If, however, the best path carrier is down for any reason, it will cease trying to communicate over that path and fail over to the other ISP.
This is very similar to the POTS example described above. If the POTS carrier in the primary location is down, the primary dialer will typically dial eight attempts and then utilize the secondary carrier to send the transmission. BGP works much the same way, but with multiple ISPs.
It is important to understand that BGP is established by the end point, which in the alarm industry is usually the central station. The central station will be issued a book of IP addresses that will be linked to at least two different ISPs. Like any form of redundancy, BGP costs more because of hardware requirements to facilitate duplicate routes and because of increased fees for the registry subscription to the American Registry for Internet Numbers (ARIN).
This is a very high level overview of BGP. If you are interested in learning more, search BGP online or contact your central station and inquire about the service. Once again, with POTS connections disappearing at an alarming rate, IP monitoring is becoming more and more popular. Employing BGP can give alarm dealers utilizing IP communications a more reliable connection to the central station.
Mark Matlock is Senior Vice President at United Central Control Inc. (UCC), a wholesale monitoring station based in San Antonio.