[pjsip] RTCP handling pjsip 1.x

Werner Dittmann Werner.Dittmann at t-online.de
Sun Jan 1 07:41:28 EST 2012


during some recent tests I saw that pjsip does not fully implement RTCP
according to RFC 3550, in particular set-up of RTCP compound packets,
refer to chap 6.1.

As noted in the subject these tests use the current  pjsip 1.x (not 2.x)
because 2.x is not yet "production-ready", isn't it? Maybe this is already
addressed in 2.x?

Using wireshark I see the following problems:

- the very first RTCP compound packet contains a SDES only. No RR, not even
  an empty RR.

- Pjsip sends SR without attaching an SDES packet

- Pjsip sends a BYE packet without an RR and an SDES

Usually this does not cause problems for RTCP implementations, however
implementations that enforce the correct set-up of RTCP compound packets may
discard RTCP compound packets and thus lose information.

Best regards,

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