Configuring Sdp Payload Types - Cisco SPA942 - - IP Phone Administration Manual

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STEP 5
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- The NTP timestamp used in the SR is a snapshot of the Cisco IP phone's
local time, not the time reported by an NTP server.
- If the Cisco IP phone receives a RR from the peer, it tries to compute the
round trip delay and show it as the
section of the web GUI administration page. It can range from 0 to 255
seconds. Defaults to 0 (recommended).
• No UDP Checksum—Select yes if you want the Cisco IP phone to calculate
the UDP header checksum for SIP messages. Since this involves
computation load, you should keep the default value (no) to disable it.
• Symmetric RTP—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.
• Stats in BYE—Determines whether the IP phone includes the P-RTP-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=<packets sent>,OS=<octets
sent>,PR=<packets received>,OR=<octets
received>,PL=<packets lost>,JI=<jitter in ms>,LA=<delay
in ms>,DU=<call duration in s>,EN=<encoder>,DE=<decoder>
Defaults to no.
Click Submit All Changes.

Configuring SDP Payload Types

Configured dynamic payloads are used for outbound calls only when the Cisco IP
phone presents an SDP offer. For inbound calls with an SDP offer, the phone
follows the caller's assigned dynamic payload type.
Cisco IP phones use the configured codec names in outbound SDP. For incoming
SDP with standard payload types of 0-95, the Cisco IP phone ignores the codec
names. For dynamic payload types, the Cisco IP phone identifies the codec by the
configured codec names (comparison is case-sensitive).
Configuring SIP, SPCP, and NAT
Call Round Trip Delay
Cisco SPA and Wireless IP Phone Administration Guide
Configuring SIP
value in the Info