[SR-Users] Packet loss / Jitter / Latency issues

Dear Daniel and Kamailio'ns Greetings, I am working on kamailio server (4.0.x),whicch is integreted with media-proxy server (2.5.2) and it is all working fine in the point of SIP functionality. And i have a set-up like this below, with this when the calls (audio/video) sessions started i am experiencing latency,jitter, echo's in audio calls and a choppy ,pixelled video : KAMAILIO | Android SIP client (IMSDroid) ---- Wi-Fi router ---- Switch (level 2) ---- Wi-Fi router ---- Android SIP client (IMSDroid) (Total set-up runs on Intranet infrastructure). When i call between two SIP clients, Calls are getting established successfully and RTP flow is also relaying using Media-proxy server. But the audio/video performnce is not good enough. I am experiencing all this Latency , jitter , Choppy pixelled video. How can i resolve all this issues? What could be the problem ? Ofcourse SIP proxy is not responsible all this problems (as i know ), But is there anything can be done on Media-proxy server ? Or anything Buffer settings can be done on Kamailio server side (or anything else) ? Even i changed Shared memory and Package memories to 512MB and 16MB respectively. Anybody can guess what may be the problems that causes these issues ? PS: When i tried 'ping' Clients IP addresses in Kamailio server PC, there is 20-30% packet loss also. Please help me in resolving these issues. Any help will greatly appreciate. Regards, Ravi.