SIP Delay Issue

Delays in milliseconds cause voice quality issues Problem: Excessive Delay High levels of delay (generally over 200 milliseconds round trip) can cause problems with conversational interaction. This may be due to the routing of the IP stream, mis-configuration of the jitter buffer at either end of the connection or high levels of jitter which are causing an adaptive jitter buffer to grow excessively large.

Impact; In the presence of high levels of delay the normal "protocol" of conversation breaks down. In addition, delay can make echo problems more obvious and annoying.

Resolution Use traceroute to verify the IP path delay. Check the  jitter level for the call and verify the configuration of the jitter buffer. The problem can occasionally be due to VoIP Gateways using excessively large voice packets or aggregating voice frames from many calls into one packet.

Tools: 

Network Analyzer, 

Traceroute, 