Johan Wikström


This document describes techniques to display presence indicators in real-time chat applications. The techniques enable accurate presence indicators with low overheads. A server compares successive timestamps to determine whether a time threshold is met. If the time threshold is met, the server pushes an updated last-seen timestamp to clients. Otherwise, the server only selectively pushes the updated last-seen timestamp to clients. The client polls the server if the last-seen timestamp meets a threshold difference from the current time. The combination of pushing by a server and polling by a client to selectively update last-seen timestamps enables accurate and consistent representation of presence state for multiple users and client devices. The techniques save server resources, network costs, and reduce energy demands on client devices.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.