摘要 |
A network access server (NAS) determines the status of availability (e.g., how much more quota is unused) of an access resource, and sends a notification embedded in a point-to-point protocol (PPP) packet. The format of the packet is chosen such that definition/use of higher layers (e.g., HTTP) is not required to communicate the status to a client system. As a result, the user may be notified even if software such as web browser is not being executed on the client system. |