Cisco SPA112 Administration Manual page 57

Configuring the Voice Settings
SIP
Cisco SPA100Series Administration Guide
Field
RTP Port Max
RTP Packet Size
Max RTP ICMP Err
RTCP Tx Interval
No UDP Checksum
Description
Maximum port number for RTP transmission and
reception.
Default setting: 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 setting: 0.030
Number of successive ICMP errors allowed when
transmitting RTP packets to the peer before the ATA
terminates the call. If value is set to 0, the ATA ignores the
limit on ICMP errors.
Default setting: 0
Interval for sending out RTCP sender reports on an active
connection. It can range from 0 to 255 seconds. During an
active connection, the ATA 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. The NTP
timestamp used in the SR is a snapshot of the local time
for the ATA, not the time reported by an NTP server. If the
ATA 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) on the Information page.
Default setting: 0
Select yes if you want the ATA to calculate the UDP
header checksum for SIP messages. Otherwise, select no.
Default setting: no
4
56