Footnote 6 in the report caught my eye: https://ieeexplore.ieee.org/document/7546510/. That’s a paper from the 2016 IEEE Symposium on Security and Privacy titled “SoK: Everyone Hates Robocalls: A Survey of Techniques Against Telephone Spam”. (My own footnote: SoK apparently stands for “systematization of knowledge” and is a type of paper which surveys existing literature without necessarily presenting new or novel research.)
This paper provides a lot of background on the robocall problem and discusses many different mitigation techniques. For each, it describes shortcomings. It’s kind of depressing, but mostly accurate.
However, in part III section H, it says: “Classified as common carriers, TSPs have an obligation to move all phone traffic with no exceptions .” TSP, which is not defined in the paper, is “Telephony Service Provider.” This seems to be saying that phone companies can’t do anything about these garbage calls.
This struck me as pretty strong language and not a mandate with which I was familiar, so I delved into footnote 19: “K. Cox, “FTC: Totally Fine By Us If Phone Companies Block Robocalling Numbers”, Jan. 2015, [online] Available: http://consumerist.com/2015/01/27/ftc-totally-fine-by-us-if-phone-companies-block-robocalling-numbers/.”
There, I found this paragraph: “Phone companies, which have been busily not blocking any of these numbers ever, insist that it is the current law that stops them. AT&T (PDF), Verizon (PDF) and the CTIA (PDF) have all filed comments to the effect that the industry is already totally on it, but that existing tools are sufficient. Further, the FCC should stay away from this, since because phones are regulated as common carriers, all carriers have an obligation to move all phone traffic, period, with no exceptions.”
Summarizing comments from the FTC (which, alongside the FCC, shares responsibility for consumer protection with respect to telephony), The Consumerist explains: “Call-blocking technology is a-ok by them, since it would ‘make a significant dent in the problem of unwanted telephone calls,’ even if, ‘to date [common] carriers have resisted offering call-blocking services to their large customer bases.’”
So now I’ve followed this from TNS, to IEEE, to The Consumerist, to AT&T, Verizon, CTIA, and FTC. What everybody is ignoring is that it is absolutely, positively A-OK for the ORIGINATING PROVIDER (or TSP, in the words of the IEEE authors) to NOT ALLOW these illegal calls to be placed to begin with.
All of these illegal robocalls enter the US telephone network through some USA-based TSP. And there is no obligation on the part of any TSP to allow a “customer” whether located in the United States or elsewhere to place thousands of calls per minute using a caller-ID of that customer’s choosing.
As far as AT&T, Verizon and the other members of CTIA are concerned: By the time the illegal traffic is passed to them, it’s generally difficult or impossible to know if it’s illegal or not, so they indeed have a tough time blocking it. The burden needs to be on the originating provider.
The statement in the IEEE paper is wrong because it doesn’t distinguish between the provider originating the calls versus those downstream. Telephone providers that allow illegal traffic to enter the network can’t hide behind some non-existent regulation.