Frequency capping helps to control the maximum number of times that you'd like each visitor to see your ad within 24 hours. A visitor is defined as the combination of 1 IP and 1 user agent. Every device that visits your ad has an IP address and a user agent. During processing, we use each IP address & user agent combination to calculate visits.
*It is possible that different people have the same IP address for different mobile devices. There are Network carriers that do not assign a unique IP address to each user, but instead have only one external IP that uses NAT (Network Address Translation) to allow multiple users to browse the web with that address. Such providers are quite rare in North America and Europe, but more common in other parts of the world. In that case, all users from that country will have the same ISP, and when that ISP uses NAT, they will also have the same IP address.