STUN (Session Traversal Utilities for NAT) is a set of methods and a network protocol to allow a host to discover its public IP address if it is located behind a NAT.
It is used to permit NAT traversal for applications of real-time voice, video and other interactive IP communications.
Our customers’ STUN servers suffered from their popularity, crashing all the time due to the heavy load. Using Sirius, we built a STUN server running on OCTEON and were able to replace one Windows server, which was a quad core Xeon running at 2.5 GHz, with just one OCTEON I processor running at 600 MHz. The new system was equipped with a rate limiter on each incoming and outgoing IP address, preventing the STUN server to be used for malicious purposes. This functionality would have been unthinkable on the Windows version.
Statistics from the Stun server. X-axis is 24 hours, Y-axis is average nr of STUN requests per second. The average for this period is 5908 requests per second at an average core load of 4%.