I have an RTP traffics which some of the packets have zero timestamps and no payloads.

Packet is :

10.. .... = Version(2)
..0. .... = Padding(false)
...0 .... = Extension(false)
.... 0000 = Contributing Source ID count(0)
0... .... = Marker(false)
Payload Type: ITU-T H.263(34)
Sequence Number: 5093
Timestamp: 0
Sync Source ID 0x572229e9

I want to know the meaning of this packet.

  • Are you able to replicate this issue, if so, can you please post tcpdump or dump of a connection to analyze? For what's it worth, the packet header is complete, it just contains no streaming data. As per RFC3550 p.11: An implementation is not required to run the Network Time Protocol in order to use RTP. Other time sources, or none at all, may be used (see the description of the NTP timestamp field in Section 6.4.1). However, running NTP may be useful for synchronizing streams transmitted from separate hosts. – Arlion Sep 17 '18 at 16:59
  • Could it be some keep-alive packet sent at intervals where no other data is to be sent, in order to keep a stream active? – Law29 Sep 17 '18 at 17:17
  • RFC6263 suggests that zero-length payloads can or are used for keep-alive, but notes that the payload type should be invalid (yours is not), and specifically recommends against using the method. The tcpdump would have been useful, as it is, no other idea. – Law29 Sep 22 '18 at 21:42

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