[SR-Users] Kamailio ERROR: _reply_light(): can't generate xxx reply when a final yyy was sent out

[Olli Attila]

Hello,

I'm getting these error messages on kamailio log from time to time:
Dec 11 19:18:30 /usr/sbin/kamailio[23913]: ERROR: tm [t_reply.c:482]:
_reply_light(): can't generate 487 reply when a final 200 was sent out
Dec  8 04:44:56 /usr/sbin/kamailio[14960]: ERROR: tm [t_reply.c:482]:
_reply_light(): can't generate 487 reply when a final 486 was sent out
Dec  5 07:46:04 /usr/sbin/kamailio[14961]: ERROR: tm [t_reply.c:482]:
_reply_light(): can't generate 487 reply when a final 480 was sent out

Kamailio is configured to act as a proxy between SBC and a softswitch.
According to the signaling we can see that these errors occure when
the SBC sends CANCEL message towards Kamailio when at the same time
final reply is received from the Softswitch side. The call seems to be
teared down nicely and finally Kamailio replies to SBC by sending "200
ok, no more pending brances". I guess Kamailio treats this situation
as an error because the sip processing engine has sent the final reply
out and at the same time SBC sends the CANCEL to Kamailio. Is there
any way we could handle this situation better on Kamailio end? The
three example ERROR messages are from cases where B subscriber has
answered the call, the B has been busy and the last one is from a case
where B subscriber has been temporarily unavailable.

Cheers,
Olli