The VoIP analysis module is only available to VoIP license users or
evaluation version users who selected VoIP evaluation mode.
The Real-time Transport Protocol (or RTP) defines a standardized
packet format for delivering audio and video over the Internet.
While protocols like SIP or H.323 are used to control the call
(e.g. setting up a connection, dialing, disconnecting, etc.), RTP
is used for reliable transmission of data packets and maintaining
Quality of Service. In other words, RTP streams carry the actual
voice payload encoded utilizing one of a number of codecs, and
analysis of RTP data provided invaluable information for assessing
call quality and troubleshooting VoIP networks.
To view RTP streams captured by the application, select
in the left pane of the VoIP analyzer window:
The upper part displays a complete list of all RTP streams. When
selecting a RTP stream from the list, the lower pane displays
detailed information on the selected stream, including the complete
list of RTP packets, summarized and statistical data, as well as
Up to four different charts for the selected stream can be
displayed simultaneously, with the window interval from 5 to 60
seconds. Note that right clicking and dragging the graph will
scroll it to the left or right respectively. The following chart
types are available:
– number of RTP packets per second including duplicates, lost
packets, and "out of order" packets.
– stream speed in terms of kilobits per second.
– average sizes of RTP packets broken down by network and RTP
headers, and RTP payload.
– stream jitter.
R-Factor, MOS Score
– stream quality estimation.
– temporal allocation of RTP packets in a stream.
The RTP Streams list contains all captured RTP streams, both
belonging to SIP or H.232 signaling sessions, and the ones for
which signaling sessions were not identified (so called 'orphan'
streams, i.e. the ones that do not belong to any parent session).
Please refer to the
chapter for more detailed information on how to exclude RTP streams
that don't have corresponding signaling sessions.
with Lists in VoIP Analyzer