One thing you’re going to hear me say again and again: It is much more efficient to stop illegal robocalls at their source, rather than trying to catch them once they’ve gotten out into the network. It’s analogous to trying to corral a bunch of horses after they’ve gotten out of the barn and dispersed into the pasture and beyond. It is much easier to prevent the illegal robocaller from launching his calls in the first place – if you can find him.
Most of the solutions to date have focused on identifying and intercepting robocalls one-by-one as they reach their destinations. That’s always been hard, but now it’s even more difficult because robocallers spoof (make up) their calling number, sometimes changing it with each call. Some have argued that it’s an intractable problem.
But that’s not a defensible argument. Every call to a USA telephone number must enter the USA telephone network through some USA telephone provider. Each of those providers is subject to a measure of regulation, and can send their calls onward only by agreement with other providers. Most phone calls only make a few “hops” to get to their destination. If an AT&T subscriber calls a Verizon subscriber, the call probably goes directly from AT&T to Verizon. A CenturyLink subscriber might find that their call to a T-Mobile subscriber goes through Inteliquent. A Sprint-to-Sprint call stays on Sprint.
Most illegal robocallers use smaller providers to initiate their calls, and that means there are usually more hops involved – three or four or even eight, as each call wends its way to its destination. The path taken by any given call won’t be readily apparent so today it takes some effort to figure out where it came from. That process is called traceback, and while it used to be an arduous process, we can now trace back selected calls in a matter of days or even hours.
When we figure out that a particular provider is the conduit for thousands or millions of calls associated with an illegal campaign (by tracing back a small sample of the calls), we can alert the provider to that fact, and they can now engage with their customer to stop the illegal activity. Corralling all those calls in one place is far more efficient than chasing them one-by-one through the network. That’s stopping the calls at the source.