A TCP/UDP proxy tunnels UDP packets over a TCP connection. It allows real time media streams to traverse firewalls which allow only outgoing TCP connections. Using Sirius, we designed a UDP tunnel device for our customer that is capable of handling tens of thousands of tunnel connections. Because there is no need to interpret the data sent through the tunnel (just send it to the UDP side if coming from TCP or vice versa) we could use Sirius’ ‘zero-copy’ feature. This will save a lot of precious CPU cycles, which would otherwise have been spent on time consuming copying of memory from one location to another.