Linksys SPA921 Cisco SPA9000 Voice System Administration Guide - Page 209

SPA9000 Field Reference Voice tab B Voice tab > SIP page RTP Parameters section The RTP parameters define the specification of the RTP audio packets. The most important parameter is the RTP Packet size (time) which defines the interval of transmission of the RTP packets. It is extremely important that time interval matches the ITSP settings. Its default value is 0.030 (30 milliseconds). NOTE These settings need to be compatible with the ITSP network settings. The ITSP you use will inform you about any specific setting you need to modify on these areas. These parameters have impact on the signaling and audio reliability. RTP Port Min RTP Port Max RTP Packet Size Max RTP ICMP Err Minimum port number for RTP transmission and reception. and should define a range that contains at least 4 even number ports, such as 100 - 106. Default: 16384 Maximum port number for RTP transmission and reception. Default: 16482 Packet size in seconds, which can range from 0.01 to 0.16. Valid values must be a multiple of 0.01 seconds. Default: 0.030 Number of successive ICMP errors allowed when transmitting RTP packets to the peer before the SPA9000 terminates the call. If value is set to 0, the SPA9000 ignores the limit on ICMP errors. Default: 0 SPA9000 Voice System Administration Guide 207