by Brian Boyko
Over at the other site I edit, Network Performance Daily, I’ve got an editorial up about VoIP and gaming, prompted by integration of VoIP into World of Warcraft. Normally NPD writes for a more technical audience but I thought it might be a good idea to give a basic rundown of the differences between TCP and UDP, and why those distinctions are important for an online gamer.
And though we’ve covered converged data and voice traffic at length before, UDP and TCP on the same network at the same time can cause network and VoIP performance problems if UDP isn’t limited to a certain quality of service. Imagine a TCP and UDP connection traveling together. TCP will, in order to make sure that the packets arrive accurately, will slow down its traffic when it senses that there’s less room in the pipe. UDP, in order to make sure that the packet arrives quickly, will see that there’s now more room in the pipe from what TCP vacated, and take up even more room… which causes TCP to slow even further. It’s a vicious cycle.