Cisco 521SG Administration Guide - Page 242

Cisco SPA IP Phone Field Reference SIP Tab A Parameter No UDP Checksum Symmetric RTP Stats In BYE Description Select yes if you want the SPA9000 to calculate the UDP header checksum for SIP messages. Otherwise, select no. Defaults to no. Enable symmetric RTP operation. If enabled, sends RTP packets to the source address and port of the last received valid inbound RTP packet. If disabled (or before the first RTP packet arrives) sends RTP to the destination as indicated in the inbound SDP. Defaults to no. Determines whether the IP phone includes the PRTP-Stat header or response to a BYE message. The header contains the RTP statistics of the current call. Select yes or no from the drop-down menu. The format of the P-RTP-Stat header is: P-RTP-State: PS=,OS=,PR=,OR=,PL=,JI=,LA=,DU=,EN=,DE=. Defaults to no. SDP Payload Types The configured dynamic payloads are used for outbound calls only where the Cisco SPA9000 presents the SDP offer. For inbound calls with a SDP offer, the Cisco SPA9000 follows the caller dynamic payload type assignments. The Cisco SPA9000 uses the configured codec names in its outbound SDP. The SPA9000 ignores the codec names in incoming SDP for standard payload types (0-95). For dynamic payload types, the Cisco SPA9000 identifies the codec by the configured codec names. Comparison is case-insensitive. Cisco Small Business SPA300 Series, SPA500 Series, and WIP310 IP Phone Administration Guide 241