In order to track loops of the participant's own data packets, it is
also necessary to keep a separate list of source transport addresses
(not identifiers) that have been found to be conflicting. Note that
this should be a short list, usually empty. Each element in this list
stores the source address plus the time when the most recent
conflicting packet was received. An element may be removed from the
list when no conflicting packet has arrived from that source for a
time on the order of 10 RTCP report intervals (see Section 6.2).
For the algorithm as shown, it is assumed that the participant's own
source identifier and state are included in the source identifier
table. The algorithm could be restructured to first make a separate
comparison against the participant's own source identifier.
IF the SSRC or CSRC identifier is not found in the source
identifier table:
THEN create a new entry storing the source transport address
and the SSRC or CSRC along with other state.
CONTINUE with normal processing.
(identifier is found in the table)
IF the source transport address from the packet matches
the one saved in the table entry for this identifier:
THEN CONTINUE with normal processing.
(an identifier collision or a loop is indicated)
IF the source identifier is not the participant's own:
THEN IF the source identifier is from an RTCP SDES chunk
containing a CNAME item that differs from the CNAME
in the table entry:
THEN (optionally) count a third-party collision.
ELSE (optionally) count a third-party loop.
ABORT processing of data packet or control element.
(a collision or loop of the participant's own data)
IF the source transport address is found in the list of
conflicting addresses:
THEN IF the source identifier is not from an RTCP SDES chunk
containing a CNAME item OR if that CNAME is the
participant's own:
Schulzrinne, et al Standards Track [Page 47]
RFC 1889 RTP January 1996
