Network traffic is generated whenever Trend Micro releases an updated version of any product component.
To reduce network traffic generated during pattern file updates, Worry-Free Services uses a method called incremental update. Instead of downloading the full updated pattern file every time, new patterns that have been added since the last release are downloaded. The Security Agent also tries to update from another Security Agent on the same network to further reduce network traffic.
For more information on the update method, see About Updates.
Regularly updated Security Agents only have to download the incremental pattern, which is approximately 5KB to 200KB. The full pattern is substantially larger even when compressed and takes longer to download.
Trend Micro releases new pattern files daily. However, if a particularly damaging virus is actively circulating, Trend Micro releases a new pattern file as soon as a pattern for the threat is available.