RTP Test

The Real-Time Transport Protocol (RTP) test includes the RTP and RTP Snoop tests.

The RTP and RTP Snoop tests are tools for detecting the telepresence network quality. Before deploying a telepresence system or starting a telepresence conference, you can use the RTP and RTP Snoop tests to detect the packet loss ratio, jitter, and delay. You can then use the statistics to evaluate whether the network quality meets the telepresence service requirements.

During a telepresence conference, you can configure the RTP Snoop test on an intermediate node to obtain network indexes such as packet loss ratio, jitter, and differentiated services code point (DSCP). This allows you to locate faults rapidly and rectify them, ensuring that the telepresence conference works properly.

Telepresence Conference Delay Detection

Figure 6-19 shows the process of detecting the delay in a telepresence conference.

Figure 6-19 Process of detecting the telepresence conference delay

1. The path from the source switch (SwitchA) to the destination switch (SwitchD) can be obtained using NMS or command line. The source switch reports the results to the NMS.
2. Using NMS or command line, the RTP test instance is configured on the source switch to detect the following for received traffic:
   • Source IP address
   • Destination IP address
   • Source UDP port number
   • Destination UDP port number
   • IP Differentiated Services Code Point (DSCP) value
3. Using NMS or command line, the intermediate switches (SwitchB and SwitchC) and destination switch are configured to prepare to receive test traffic.
4. The source switch constructs an RTP packet and starts to send test traffic.
5. The intermediate switches and destination switch receive the RTP packet and send a reply packet to SwitchA.
6. SwitchA receives the reply packet and calculates the delay in receiving the packet.
7. The NMS server sends a message to the source switch to obtain the delay statistics.

Telepresence conference packet loss ratio and jitter detection

Figure 6-20 shows the process of detecting the packet loss ratio and jitter of a telepresence conference.

Figure 6-20 Process of detecting the packet loss ratio and jitter of a telepresence conference

1. The path from the source switch (SwitchA) to the destination switch (SwitchD) can be obtained using NMS or command line. The source switch reports the results to the NMS.
2. Using NMS or command line, the RTP test instance is configured on the source switch to detect the following for received traffic:
   • Source IP address
   • Destination IP address
   • Source UDP port number
   • Destination UDP port number
   • IP DSCP value
3. Using NMS or command line, the intermediate switches (SwitchB and SwitchC) and destination switch are configured to detect the RTP Snoop test instance.
4. The NMS sends a message to the intermediate switches and destination switch, starts the RTP Snoop test instance, and notifies the switches of the snooping time.
5. The intermediate switches and destination switch calculate the packet loss ratio and jitter, and report the IP DSCP values of packets.
6. The NMS server sends a message to the intermediate switches and destination switch to obtain detection statistics and IP DSCP values of packets.
7. The intermediate switches and destination switch send statistics about the packet loss ratio, jitter, and packet priority change to the NMS. The NMS identifies links of low network quality.