TETRA module
The TETRA module shows information about TETRA (Terrestrial Trunked Radio) traffic, used for professional mobile radio communication. Recognized traffic types include call packets for delivering speech data and keep-alive packets sent from the client devices to inform about their availability. Data is transferred via UDP packets, so data integrity is handled by the TETRA protocol:
- for each packet sent from an origin peer to its destination peer (request packets), the destination replies a response packet to the origin.
- every packet contains a sequence number, so that the destination can arrange received packets in the correct sequence.
Overview
Information about all recognized TETRA packets are shown as values and graphs to give a quick overview. Global traffic can be shown in the traffic graph to see the share of TETRA traffic on the overall traffic. Measures of packets and data (accumulated and as per second rate) provide an impression of the used capacity. Request-response times show the time difference between request packets and their corresponding response packets. Problems in the packet sequence are available as counters for lost packets (expected sequence number missing), repeated packets (sequence number seen multiple times) and reordered packets (sequence numbers not in expected order). For call packets, the maximum packet jitter is shown. A PCAP download button allows capturing that traffic.
Connections
All connections with their source and destination IPs and ports are shown. Besides general packet counts, specific packet type counts can be selected for call- and keep-alive-packets. For both types request packets, acknowledged and not acknowledged/erroneous packets are accounted separately. Connection problems can be identified using counters for lost, repeated or reordered packets and by evaluating packet response times. To assess call quality, the maximum jitter of call packets is shown. For having a quick overview, multiple graphs can be shown simultaneously for:
- general TETRA traffic rate
- rate of keep-alive packets in comparison with all TETRA packets
- rate of call packets in comparison with all TETRA packets
- rate of keep-alive request-, ACK- and NACK-response packets
- rate of call request-, ACK- and NACK-response packets
- call packet jitter
- packet response times
- rate of lost call request- and response packets
- rate of lost keep-alive request and response packets
- rate of reordered call- and keep-alive packets
- rate of repeated keep-alive request-, ACK- and NACK-response packets
- rate of repeated call request-, ACK- and NACK-response packets
The TETRA traffic of each connection can be captured using the PCAP download button.
A basic filter can be used to limit the shown connections to specific IPs, subnets or host names.