An Update on Robocalling

The FCC has continued to push for a solution to reduce nuisance robocalls. A solution is badly needed. YouMail tracks nationwide robocalls and publishes the results on this Robocall index. They estimate that there were over 4.1 billion robocalls in March 2020 or about 12.5 calls for every telephone subscriber in the country. According to their index, the number of robocalls peaked in October of last year with an astounding 5.6 billion calls that month. Not all robocalls are bad. For example, when my daughter was in high school we got robocalls for parents to remind us of things that we likely wouldn’t otherwise be told.

One of the services our firm offers is doing telephone surveys for marketing purposes, and my callers report that a significant percentage of people that we call won’t pick up their calls, which are always a long-distance call from out of region. People have gotten leery about calls from numbers they don’t recognize.

The industry is now scheduled to implement a STIR/SHAKEN solution by June 2021. The STIR acronym stands for Secure Telephony Identity Revisited and creates a trust value score for originating calls, which represent the level of assurance that the originating carrier has in the legitimacy of the call. SHAKEN stands for Signature-based Handling of Asserted information using toKENs is a set of guidelines for carriers that terminate calls that define how carriers should react to STIR information that has crossed the network.

It’s worth noting that this new technology doesn’t block any robocalls, although I’ve seen the general press assume that’s how the industry will be handling robocalls. Instead, the STIR/SHAKEN protocols are a classification system where originating carriers attest to the validity of calls. For example, there is a STIR code for full attestation where the originating service provider authenticates that the call came from on of their customers and that the customer was authorized to use the phone number used to make the call. Carriers that receive calls with that full attestation will deliver the calls like normal to customers.

For calls with lesser levels of authentication, carriers will decide how to handle the calls with customers. I’m already seeing some of this on my AT&T cellphone. I’ve received at least a dozen calls in the last few months where AT&T labels the Caller ID as ‘SPAM Call’. I haven’t answered any of these calls and I guess I should, just to see if they are robocalls or something else. There is a good description of the mechanics of the STIR/SHAKEN process at the bandwidth.com website that’s not too technical.

There is still one big flaw in the new protocols in that STIR/SHAKEN only works for Voice over IP calls. Such calls are already fully digital and the protocols are able to layer on the STIR attestation data along with delivering a call. However, traditional TDM phone calls won’t work with the new protocols since there is no easy way to transmit additional data about the call for use by terminating telephone companies.

There are still a lot of traditional TDM phones in the world. It’s been estimated that 40% of residential landlines and almost half of business telephone lines are still using TDM technology. Everybody with a copper telephone line from a telco likely still uses traditional TDM voice technology. The business/government market still uses a lot of TDM technology, using either individual telephone lines, traditional Centrex service, or PBXs that use channelized PRIs to carry voice traffic. Almost no international calls, except calls from Canada, will use the STIR protocol.

None of the calls originating on traditional phone switches will carry the STIR attestation information. There is a huge concern from rural telephone companies which fear that calls from their customers will be labeled as spam. Businesses that use older phone technology are going to have the same concerns. There are general guidelines that tell the companies that terminate and deliver calls to customers how to deal with the various STIR protocols. But there is nothing to stop a telco from being cautious and labeling all calls without the STIR designation as spam. The calls would still be delivered, but how many people will answer such calls?

There is also a concern that robocallers will only originate calls through TDM phone systems. By doing so they still might get calls delivered if telcos allow other TDM calls. Robocall companies are likely going to be like computer spam, and robocallers will change tactics to defeat the STIR protocols.

Small telcos have a dilemma. Most of them have lost over half of their customers over time and have lost half of the calling volume from the customers that remain. There is no easy or affordable path for somebody originating calls on a copper network to convert them to VoIP. Rural America has already suffered for years by long-distance routing schemes that fail to deliver calls to rural markets. Rural telephony gets really screwed if calls originating from rural areas are also no longer trusted.

The FCC knows about these limitations and is moving forward anyway. Robocalls are a huge problem and the FCC has been under fire from Congress to do something, so they acted. But there is still a lot of risk that much of our phone calling is going to get gummed up with the cutover to STIR/SHAKEN – particularly calls coming from rural America.

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