Andrew,

Congratulations on your new position as a Kamailio developer! When I saw your module (SCA) I began testing immediately since it may be a stepping stone to help me get the Polycom barge-in feature working with Kamailio. However, I ran into a few difficulties. Can you assist me?

To make your existing code work as a K module I had to change a few lines of code and recompile under modules_k. Specifically, since the K definition of the ucontact structure defines ucontact->aor as str* and the S definition as str**, I changed “&c->aor” to “c->aor” in the following lines of sca_usrloc_cb.c:

73: if ( !sca_uri_is_shared_appearance( sca, c->aor )) {
74: LM_DBG( "%.*s is not a shared appearance line", STR_FMT( c->aor ));

79: &SCA_EVENT_NAME_CALL_INFO, c->aor ) < 0 ) {

Since I use PostgreSQL as my SQL engine I created the SCA entries using this code:

INSERT INTO version (table_name, table_version) values ('sca_subscriptions', '0');
CREATE TABLE sca_subscriptions (
id SERIAL PRIMARY KEY NOT NULL,

subscriber VARCHAR(255) NOT NULL,
aor VARCHAR(255) NOT NULL,
event INTEGER NOT NULL,
expires INTEGER NOT NULL,
state INTEGER NOT NULL,
app_idx INTEGER NOT NULL,

call_id VARCHAR(255) NOT NULL,
from_tag VARCHAR(128) NOT NULL,
to_tag VARCHAR(128) NOT NULL,
notify_cseq INTEGER NOT NULL,
subscribe_cseq INTEGER NOT NULL,

CONSTRAINT sca_subscriptions_idx UNIQUE (subscriber, call_id, from_tag, to_tag));

I applied the recommendations from your documentation on configuring Kamailio (3.3.1) and inserted the call to “sca_handle_subscribe ()” in kamailio.cfg.

Next, I connected two Polycom phones (SP335 and SP650) to my network and configured them to enable presence and use a shared line. Four lines were configured on the phones as shown below:

SP335 Line 1 (p11) = private line 6013
SP335 Line 1 (p12) = shared line 1519
SP650 Line 1 (p21) = private line 6014
SP650 Line 2 (p22) = shared line 1519

My tests get inconsistent results on the line LEDs and it seems that they do not work as a shared line. When I ran a tcpdump of the SIP communication (see attached pcap files) I found several anomalies:

Some packets (sca-reboot1 #22, 44, 113, 120 and sca-reboot2 #17, 38) contain spurious NUL characters in the tags section. In all tests it seems to occur in the Expire tag when Kamailio accepts the subscription.
When Kamailio sends call-info NOTIFY the Content-Length tag is missing.
Sometimes the phone does not respond to a call-info NOTIFY event (sca-reboot1 #23, 45 and sca-reboot2 #18, 39).
I don't have an example here but sometimes the phones respond to the call-info NOTIFY with "481 Call Leg/Transaction Does Not Exist".

I think some of my problems are related to these anomalies. Could you help me to determine if this is a problem with the code itself, my failure to properly port it to the K module, or some other issue?

Once again, thank you for making this very useful module for Kamailio and for the documentation to make it work. I hope that resolving my problems may help the code to become a part of Kamailio.

Sincerely yours,

Bob Boisvert