[Spce-user] Re-INVITE Issue

Steven Saner ssaner at hubris.net
Wed Aug 5 15:34:11 EDT 2015

I have a situation that is causing me some problems. I'm using SPCE mr3.8.2.

The scenario is that a call comes into the proxy from a peer and then is
terminated by a subscriber device. The device in use is an Adtran TA908
IAD, which is simply connecting a SIP call to an FXS port and some
legacy telephony device. If the Adtran is configured to just dump the
incoming call to an FXS port everything works fine.

However, in this case, there is a "ring-group" configured on the Adtran
to accept the inbound call and then deliver it to one of a pool of FXS
ports that isn't in use. When the call is transferred from the
ring-group to an FXS port, the Adtran does a re-INVITE back towards the
proxy server.

This re-INVITE is apparently not working properly. The call is
established and the two parties can talk to each other, but at exactly 1
minute into the call, the call drops. The call is dropped by the proxy
server in that the drop is initiated by the proxy sending a BYE to both
the peer and the subscriber, both of which return an OK. So from the end
points, it looks like a normal call clearing.

When this re-INVITE comes in from the subscriber side, Kamailio throws
the following two errors in the kamailio-proxy.log

Aug  4 15:51:23 sipproxy2 proxy[22685]: ERROR: rtpengine
[rtpengine.c:1709]: select_rtpp_node(): script error -no valid set selected
Aug  4 15:51:23 sipproxy2 proxy[22685]: ERROR: rtpengine
[rtpengine.c:1442]: rtpp_function_call(): no available proxies

I would have to guess that something in the proxy server is timing out
at exactly 1 minute. The question is what. Its almost as if when the
re-INVITE comes in, it is establishing a new call or a new proxy
instance maybe, but then the old call is timing out and sending the BYE
signal to both ends and thus terminating the call.

Can someone shed some light on this?



Steven Saner <ssaner at hubris.net>                      Voice:  316-858-3000
Director of Network Operations                          Fax:  316-858-3001
Hubris Communications                                http://www.hubris.net

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