[Serusers] rtpproxy locks up ser

Hi, I don't know if anyone has experienced this. The ser stops getting any packets, ser log shows no activity. When I do "netstat -an", I got this, Proto Recv-Q Send-Q Local Address Foreign Address State udp 261580 0 80.1.2.3:5060 0.0.0.0:* udp 85224 0 0.0.0.0:35940 0.0.0.0:* udp 0 0 0.0.0.0:35941 0.0.0.0:* udp 47704 0 0.0.0.0:35942 0.0.0.0:* udp 0 0 0.0.0.0:35943 0.0.0.0:* I restarted ser several times, didn't help. So I restarted rtpproxy. Ser started processing packets and the recv-q drops to 0. I wonder what could cause recv-Q accumulating packets. Everything was running fine without any problem for a long time. I haven't made any change to either ser or rtpproxy recently. Any suggestions? Thanks, Richard