> Are there any high realtime and stable protocol(opensource & > commerical)? In the LAN communication, the delay time MUST be > less than 10ms for the small packets. Apparently, there is a protocol called Real Time Protocol (RTP), augmented by something called RTP Control Protocol (RTCP). Its stated purpose is to carry real-time sensitive data such as audio, video and the like. More information can be found on it here: http://www.cs.columbia.edu/~hgs/rtp/ -- [ Tobias DiPasquale ] 0x636f6465736c696e67657240676d61696c2e636f6d - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html