Adaptive Routing: It’s Like a GPS for Your SMS

Published March 31, 2015 by James Winter

If you ask someone who’s responsible for implementing or managing SMS if they ever have problems, the answer will almost always be “yes”. There are a number of issues that impact SMS delivery because it was never intended to be a business communication tool.

As experts in the industry, Nexmo knew it had to solve some of those issues in order to provide some stability in the otherwise chaotic landscape. To address the problem of inconsistent SMS delivery on the international scale, Nexmo developed Adaptive Routing — a system that works like a navigation system for SMS which constantly monitors and changes routes to ensure the fastest, most consistent quality possible.

To understand why SMS has been unreliable for businesses the world over, we first need to talk a little history.

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A Brief History: How Hard Can It Be?

A few decades ago, when SMS first started becoming a valid person-to-person communications tool, the carriers agreed they would assume all traffic was even rather than keep track of how many SMS messages they sent each other. After all, if user #1 sends a message to user #2 in another country, most likely there will be a reply back.

This agreement between carriers provided an opening that some of the more intrepid entrepreneurs began to exploit. They realized that if they registered as carriers, they would be able to send messages to other carriers carte blanche without having to pay.

Instead of having mobile phone subscribers as customers, these fake carriers served businesses who wanted to send SMS, traditionally for outbound marketing campaigns, to customers around the world. These companies became known as aggregators, and they began to cause problems for carriers the world over.

The SMS Aggregator Model

Typically, these aggregators achieved their reach by connecting to other aggregators, creating a situation where your message might go through as many as five different entities before being delivered, hopefully intact, to its final destination. Because quality was never high on the list of priorities to many of these companies, real-time reporting and measurement were not possible.

With SMS, the saying, “You get what you pay for,” is highly relevant. If someone is offering a much lower price to a certain country than the rest of the competition, oftentimes it means they are using a grey route. Grey routes are questionably legal routes that violate the receiving countries’ regulations and often come in the form of SIM boxes — specially designed hardware that receive SIM cards meant for consumer use, but instead are combined together to provide extremely cheap SMS for a business (read more about it here).

These aggregators traditionally operate on a concept called “least cost routing.” Since you get what you pay for, the cheaper the route increases the likelihood your message will arrive late, or not at all.


How Can I Measure My SMS Quality?

Unfortunately, the almost accidental nature of the development of SMS did not take into account a good way to measure international message delivery quality. The traditional industry standard measurement, the DLR (Delivery Receipt), is not always a trustworthy source of information. In some places, aggregators or carriers will not provide reliable information or even fake the delivery of the message.

Nexmo knew it needed a better way to measure the quality of particular SMS routes, and so the Conversion API was born. Because Nexmo differentiated itself from the competition based on quality of delivery, a better method than the DLR was necessary. The Conversion API uses a user action to indicate that the message was received, and is impossible to fake. For instance, when a time-based one-time password (TOTP) message is sent, the message will only be considered successful when the user enters that password.


The Solution

When Nexmo was created, it was founded on the idea that SMS should be a reliable, business critical solution that would help companies engage with their users no matter where they were. Unfortunately, the legacy infrastructure and lack of quality controls has made it difficult for many businesses to trust SMS providers. Oftentimes, they can’t react at the speed needed to ensure a high quality of delivery.

Nexmo created the Adaptive Routing algorithm in order to alleviate the uncertainty present in global SMS. With Adaptive Routing, Nexmo’s SMS routes are tested multiple times per hour using millions of data points to ensure that a route has not lost its effectiveness. By doing so, Nexmo is able to truly provide a business critical SMS solution that our customers can rely on.