UDP (User Datagram Protocol) - communication protocol in local networks or Internet, with minimal delays and minimal stability.
With Astra you can analyze any supported source. Just launch in console next command:
astra --analyze "udp://[email protected]:1234"
To stop Astra analyzer press Ctrl+C. Read more about Astra MPEG-TS Analyzer
Tcpdump is a common tool to check network traffic. For example, command to check UDP multicast receiving to group 188.8.131.52 on the interface eth0:
tcpdump -pnni eth0 udp and host 184.108.40.206
If you don't know actual interface you may find it with command:
ip route get 220.127.116.11
The tcpdump output looks like many lines with information about packets source, destination, and length. For example:
21:38:42.143839 IP 192.168.88.100.33610 > 18.104.22.168.1234: UDP, length 1316 21:38:42.143868 IP 192.168.88.100.33610 > 22.214.171.124.1234: UDP, length 1316
To stop tcpdump press Ctrl+C
Not working means a zero bitrate in the Astra MPEG-TS Analyzer output. For example:
Jan 27 09:00:00: INFO: Bitrate: 0 Kbit/s Jan 27 09:00:01: INFO: Bitrate: 0 Kbit/s
First of all check traffic on the network interface with tcpdump tool. If there is no information about incoming packets, then need to check network configuration or source configuration.
If tcpdump shows information about UDP packets, there is could be next issues:
CC (Continuity Counter) errors indicates that packets continuity is corrupted. Error can be caused by packets loss or excess. Example output with CC errors in the Astra MPEG-TS Analyzer:
Jan 27 09:00:00: INFO: Bitrate: 13259 Kbit/s Jan 27 09:00:00: ERROR: CC: PID:18=3 PID:20=3 PID:256=24 Jan 27 09:00:01: INFO: Bitrate: 13261 Kbit/s Jan 27 09:00:01: ERROR: CC: PID:18=5 PID:20=2
There is two common issues: packets loss or packets excess.
Excess packets looks in the tcpdump output as packets from different sources to the same destination:
21:38:42.143839 IP 192.168.88.100.33610 > 126.96.36.199.1234: UDP, length 1316 21:38:42.143868 IP 192.168.88.100.24081 > 188.8.131.52.1234: UDP, length 1316
There is could be two causes:
In both cases need to check remote server configuration. If this is not possible or as temporary solution you can drop packets from second source with firewall.
First of all need to check losses and errors on the network interface:
ip -s link show eth0
You need to look at RX Errors. Some network cards provide more detailed information about the nature of the loss:
ethtool -S eth1
Losses can be not only on the network cards of your server. They can also be on the network equipment port. You can find the informaton how to see it in the documentation of the network equipment manufacturer. Where eth0 is an interface name. After the RX-row will be row with numbers. Third number is an UDP receiving errors.