The problem with UDP is that there is no explicit feedback-loop or congestion control frobs -- this is generally kicked up the protocol stack for the application itself to figure out. UDP is designed that way: push traffic into the network as fast as the network can take it, and expect the application to provide for delay/loss/adaptation of jitter, buffering, etc. So to answer your question, I think it really depends on how the application itself handles UDP traffic, adapts to any sort of RTT measurements, delay/jitter, etc. - ferg -- "Gunther Stammwitz" <gstammw@gmx.net> wrote: Hello colleages, I'm trying to find out how one can measure the performance or quality of a network for gamers and voip-users. Both applications are very sensitive to packetloss, delays or jitter since they're using udp instead of tcp and are very timing critical. ==> Which tools (under linux) are you using in order to measure your own network ore on of your upstreams in terms of "gameability" or voip-usage? Ordinary pings won't help since routers are regulary dropping them and even an end-to-end ping is not perfect since one of the hosts might be busy or something like that? Starting your favorite online game and play on a server that is being housed in your own network isn't the solutions I'm looking for :-( Your ideas are appreciated :-) Gunther -- "Fergie", a.k.a. Paul Ferguson Engineering Architecture for the Internet fergdawg@netzero.net or fergdawg@sbcglobal.net ferg's tech blog: http://fergdawg.blogspot.com/