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5G-MAG / rt-mbms-modem

MBMS - Modem
https://www.5g-mag.com/5gbroadcast
GNU Affero General Public License v3.0
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The 5gmag modem receives normally, but cannot receive IP packets from Ethernet #33

Closed Flash0406 closed 2 years ago

Flash0406 commented 2 years ago

Hi 5G-MAG expert group，

We use our own 5g broadcast transmitter to connect with 5gmag receiver . The 5gmag receiver works normally, but the IP packet cannot be obtained from Ethernet.

However, when we use sample file to receive, we can obtain IP packets in the same environment.

By comparing the log files generated by the two modes, it is found that the process has reached GW write pdu MCH function. There are both printing messages such as "RX MCH PDU...." and there is no error message about "DL TUN / TAP".

Attach file is contain syslog for two test mode. FIle “syslog_20220401_right“ is reported when using sample file and “syslog_20220401_wrong“ is reported when using SDR. debug_log.zip

Please help to see where is the problem, thanks!

Flash0406 commented 2 years ago

when VLC is used to generate RTP video IP streams on PC TX, the TTL (Time to Live) in these IP packets is set to 0x1. When the 5G-MAG receiver parsed the IP packet from the MCH and sent it to the Ubuntu Ethernet module, the Ethernet module found TTL=0x1 and discarded the IP packet.

dsilhavy commented 2 years ago

Thank you for pointing this out @Flash0406 . As an addition the basic architecture:

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