Help Center SMS Routing Understanding A2P Traffic and the Intricacies of 'Grey Routes

Understanding A2P Traffic and the Intricacies of 'Grey Routes

A2P Traffic through Sim Boxes:

One prevalent method of handling A2P traffic is using sim boxes, also known as modem farms. In this setup, A2P traffic is directed through sim cards placed in modems, designed primarily for P2P purposes. The attraction of this method is its cost-effectiveness and the capability to transmit a high volume of messages without immediate detection. It simulates human behavior, as operators are led to believe these messages stem from human users. However, to maintain this facade, the distribution of messages across sims is crucial to avoid overloading a single sim, which would be an unnatural pattern for a human user.

Grey Routes and the SS7 Network:

The term 'Grey Route' often encompasses certain SS7 pathways. The SS7 is an international signaling system used by operators for exchanging P2P traffic. While some operators might reconcile through a 'net-off' arrangement, others might bill based on an AA19 agreement. SMS Gateways connected to an operator or the SS7 can transmit their messages at a low cost. When there's a direct link to an operator or SS7, labeling the route as 'grey' might be inappropriate. However, the more intermediaries involved, the higher the chances of delivery lags and diminished quality, pushing the route closer to the 'grey' territory. The lack of clear commercial agreements between senders and receiving operators makes A2P traffic vulnerable. Given the distinct patterns of bulk SMS A2P traffic—short duration, high volume, and recurring features like Sender IDs—operators can easily spot and block such traffic.


For consistent and authentic SMS traffic, it's advisable to engage with suppliers having direct connections to country or regional operators or those utilizing a 1-hop strategy through local affiliates with direct ties to these operators.