PAP is used for communicating with the Push Proxy Gateway, which is usually part of a WAP Gateway.
PAP is intended for use in delivering content from Push Initiators to Push Proxy Gateways for subsequent delivery to narrow band devices, including mobile phones and pagers. Example messages include news, stock quotes, weather, traffic reports, and notification of events such as email arrival. With Push functionality, users are able to receive information without having to request it.