Using Rtcp In The Ip Telephone - Avaya T3 Service Manual

Using RTCP in the IP telephone

The RTCP protocol supplies current information about the quality of the voice data in
the network, doing so on the basis of the RTP packets received and sent. This feedback
allows the system administrator to manually adapt to network conditions the data stream
generated by them (for example, by reducing the data rate in the case of a poor QoS)
and to locate faults. To do so, RTCP periodically transmits so-called sender reports (SR)
and receiver reports (RR). The reports received are saved for statistical purposes. (For
more detailed information about RTCP: RTP - A Transport Protocol for Real-Time-
Applications, RFC 1889, Januar 1996).
Activation of RTCP and the associated logging can be set in the Audit menu. Logging
occurs on an FTP server. The data is filed there in csv format.
Note: An FTP server address for logging has to be previously entered in the Web
terminal.
Evaluating the csv log file
Every RTCP report received or sent is documented on a separate line. The values from
the reports are shown in hexadecimal form.
The individual data are separated by semicolons in the file.
Version
Time stamp
Direction
Report type
SSRC source
NTP time sec
NTP time frac
RTP time stamp
Packets count
Octets count
SSRC report block
Fraction lost
Cum. no. of packets
lost:
Highest seq. No. Rx:
Interarrival jitter
Max. interarrival time:
Round trip delay
Logging version
Time stamp DD.MM.YYYY SS
Received / sent RTCP report (RX/TX)
Packet type, type of report according to RFC 1889
Synchronisation source identifier of the sender
Sender information
NTP time stamp, 64-bit time indication, when the report was
sent
Time stamp, when the packet which corresponds to the RTP
time stamp was sent
Number of RTP packets which were sent
Quantity in bytes of the voice data which was sent
Synchronisation source identifier of the source for which the
report is determined
Percentage of RTP packets not received
The number of RTP packets lost during the call
Report block info
Variance in the arrival times of the RTP packets
Max. time in ms of intervals at which RTP packets arrive at the
IP telephone
Time in ms which an IP frame requires to be transmitted to the
called station and back
Menus of the IP telephone
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