Linksys BUSINESS SPA922 - Manual (Page 143)

Linksys SPA9x2 Phone Administration Guide
Cisco Confidential--First Draft
136
SIP Tab
SPA9x2 Phone Field Reference
RTCP Tx Interval Interval for sending out RTCP sender reports on an active
connection. It can range from 0 to 255 seconds. During
an active connection, the SPA9x2 can be programmed to
send out compound RTCP packet on the connection.
Each compound RTP packet except the last one contains
a SR (Sender Report) and a SDES (Source Description).
The last RTCP packet contains an additional BYE packet.
Each SR except the last one contains exactly 1 RR
(Receiver Report); the last SR carries no RR. The SDES
contains CNAME, NAME, and TOOL identifiers. The
CNAME is set to <User ID>@<Proxy>, NAME is set to
<Display Name> (or Anonymous if user blocks caller ID),
and TOOL is set to the Vendor/Hardware-platform-
software-version (such as Linksys/SPA9x2-1.0.31(b)). The
NTP timestamp used in the SR is a snapshot of the
SPA9x2’s local time, not the time reported by an NTP
server. If the SPA9x2 receives a RR from the peer, it
attempts to compute the round trip delay and show it as
the <Call Round Trip Delay> value (ms) in the Info
section of SPA9x2 web page.
Defaults to 0.
No UDP Checksum Select yes if you want the SPA9x2 to calculate the UDP
header checksum for SIP messages. Otherwise, select no.
Defaults to no.
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 yes.
Stats In BYE Determines whether the SPA9x2 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.
Parameter Description