Contacts replacing each other when registering - sr-users

27 Sep 2016

Hi,

we are running a Registrar server with 4.4.3, the registrar module is
configured with the following parameters:

modparam("registrar", "max_contacts", 50)
modparam("registrar", "use_path", 1)
modparam("registrar", "path_mode", 0)
modparam("registrar", "path_use_received", 1)
modparam("registrar", "received_avp", "$(avp(i:801))")
modparam("registrar", "default_expires", 600)
modparam("registrar", "min_expires", 60)
modparam("registrar", "max_expires", 600)
modparam("registrar", "gruu_enabled", 0)

A customer has configured 4 phones with the same username. Normally,
all 4 phones would be visible in the location database, and incoming
calls would fork out to all 4 phones. However, only one of the devices
is always online, the others always replace each other on each
registration.

Client details:
* All phones are snom 715 devices with the same firmware version.
* All phones sit behind the same router.

Registrations:
client 1:
* Via: SIP/2.0/UDP 192.168.208.91:35812;branch=z9hG4bK-4q0mmxgu6gm7;rport
* Contact:
<sip:1794388e3@192.168.208.91:35812;line=gicode6v>;reg-id=1;q=1.0;+sip.instance="<urn:uuid:0a14174a-77be-424c-864e-0004137F1C9D>"

client 2:
* Via: SIP/2.0/UDP 192.168.208.90:41331;branch=z9hG4bK-3cbxdvbmk0di;rport
* Contact:
<sip:1794388e3@192.168.208.90:41331;line=0j6veso8>;reg-id=1;q=1.0;+sip.instance="<urn:uuid:0a14174a-77be-424c-864e-0004137F1C9D>"

client 3:
* Via: SIP/2.0/UDP 192.168.208.92:5360;branch=z9hG4bK-4drsogakez94;rport
* Contact:
<sip:1794388e3@192.168.208.92:5360;line=0n7jfzih>;reg-id=1;q=1.0;+sip.instance="<urn:uuid:0a14174a-77be-424c-864e-0004137F1C9D>"

client 4:
* Via: SIP/2.0/UDP 192.168.208.93:5260;branch=z9hG4bK-1ci0qia3yxyl;rport
* Contact: <sip:1794388e3@192.168.208.93:5260;line=mh9sgxa1>;reg-id=1;q=1.0

Only client 4 is reachable all the time. The other 3 clients replace
other registrations.

So after client 1 registers, the contacts returned in the 200 OK looks
like this:

Contact:
<sip:1794388e3@192.168.208.91:35812;line=gicode6v>;q=1;expires=600;received="sip:1.2.3.4:6411";+sip.instance="<urn:uuid:0a14174a-77be-424c-864e-0004137F1C9D>";reg-id=1,
<sip:1794388e3@192.168.208.93:5260;line=mh9sgxa1>;q=1;expires=303;received="sip:1.2.3.4:8923"

And after client 2 registers, the contacts returned in the 200 OK
looks like this:

Contact:
<sip:1794388e3@192.168.208.90:41331;line=0j6veso8>;q=1;expires=600;received="sip:1.2.3.4:49061";+sip.instance="<urn:uuid:0a14174a-77be-424c-864e-0004137F1C9D>";reg-id=1,
<sip:1794388e3@192.168.208.93:5260;line=mh9sgxa1>;q=1;expires=301;received="sip:1.2.3.4:8923"

So you see, one contact stays the same, the other one gets replaced.

Does anybody know what could cause this kind of behavior? I think, it
could be GRUU. I see that those three clients all send the same GRUU
parameter. From my understanding, this UUID should be different from
client to client. I don't know whether this is a bug in the snom
firmware always sending the same GRUU UUID or whether som
"intelligent" SIP aware router is putting this in the Contact header.
However, since we have disabled gruu for the registrar module (see
above), I think, Kamailio should ignore it.

Ideas? Thanks in advance.

Best Regards,
Sebastian