ser作为一个高效、高度可配置的simple服务器，结合sip协议的特点采用mediaproxy来实现NAT穿越和负载均衡-with a high effeciency and flexibility sip express router ,ser implemente the function of transversing NAT by the mediaproxy

结合OpenSIPs作为高效可扩展的传输媒体流服务器。-MediaProxy is a media relay for RTP/RTCP and UDP streams that works in tandem with OpenSIPs to provide NAT traversal capability for media streams from SIP user agents located behind NAT.