Here’s a piece of log with RTP debugging enabled:
RTP Debugging Enabled
== Using SIP RTP CoS mark 5
[Apr 8 18:05:26] NOTICE[8002][C-00002a8a]: chan_sip.c:25620 handle_request_invite: Call from '' (***.**.**.**:5092) to extension '000972598601694' rejected because extension not found in context 'default'.
[Apr 8 18:05:58] WARNING[8002]: chan_sip.c:3996 retrans_pkt: Retransmission timeout reached on transmission 79fb41cfdd41551e6d4781797e6e3385 for seqno 1 (Critical Response) -- See https://wiki.asterisk.org/wiki/display/AST/SIP+Retransmissions
Packet timed out after 32001ms with no response
-- Unregistered SIP '7000'
-- Registered SIP '7000' at **.***.***.***:53599
== Using SIP RTP CoS mark 5
-- Executing [6946@default:1] Dial("SIP/7000-00002330", "SIP/6946,30") in new stack
== Using SIP RTP CoS mark 5
-- Called SIP/6946
-- SIP/6946-00002331 is ringing
-- SIP/6946-00002331 answered SIP/7000-00002330
-- Channel SIP/7000-00002330 joined 'simple_bridge' basic-bridge <bdbd4521-abd3-4ed1-992e-c50424310e54>
-- Channel SIP/6946-00002331 joined 'simple_bridge' basic-bridge <bdbd4521-abd3-4ed1-992e-c50424310e54>
Got RTP packet from **.***.**.***:31891 (type 00, seq 052190, ts 3218617609, len 000160)
Got RTP packet from **.***.***.***:54242 (type 00, seq 049940, ts 2650177671, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001476, ts 2650177664, len 000160)
-- Started music on hold, class 'default', on channel 'SIP/6946-00002331'
Sent RTP packet to **.***.***.***:33072 (type 00, seq 001477, ts 2650231152, len 000160)
Sent RTP packet to **.***.***.***:33072 (type 00, seq 001478, ts 2650231312, len 000160)
Sent RTP packet to **.***.***.***:33072 (type 00, seq 001479, ts 2650231472, len 000160)
Sent RTP packet to **.***.***.***:33072 (type 00, seq 001480, ts 2650231632, len 000160)
Sent RTP packet to **.***.***.***:33072 (type 00, seq 001481, ts 2650231792, len 000160)
Sent RTP packet to **.***.***.***:33072 (type 00, seq 001482, ts 2650231952, len 000160)
Sent RTP packet to **.***.***.***:33072 (type 00, seq 001483, ts 2650232112, len 000160)
Sent RTP packet to **.***.***.***:33072 (type 00, seq 001484, ts 2650232272, len 000160)
Sent RTP packet to **.***.***.***:33072 (type 00, seq 001485, ts 2650232432, len 000160)
Sent RTP packet to **.***.***.***:33072 (type 00, seq 001486, ts 2650232592, len 000160)
Sent RTP packet to **.***.***.***:33072 (type 00, seq 001487, ts 2650232752, len 000160)
Sent RTP packet to **.***.***.***:33072 (type 00, seq 001488, ts 2650232912, len 000160)
Sent RTP packet to **.***.***.***:33072 (type 00, seq 001489, ts 2650233072, len 000160)
Sent RTP packet to **.***.***.***:33072 (type 00, seq 001490, ts 2650233232, len 000160)
Sent RTP packet to **.***.***.***:33072 (type 00, seq 001491, ts 2650233392, len 000160)
Sent RTP packet to **.***.***.***:33072 (type 00, seq 001492, ts 2650233552, len 000160)
Sent RTP packet to **.***.***.***:33072 (type 00, seq 001493, ts 2650233712, len 000160)
Sent RTP packet to **.***.***.***:33072 (type 00, seq 001494, ts 2650233872, len 000160)
Sent RTP packet to **.***.***.***:33072 (type 00, seq 001495, ts 2650234032, len 000160)
Sent RTP packet to **.***.***.***:33072 (type 00, seq 001496, ts 2650234192, len 000160)
Sent RTP packet to **.***.***.***:33072 (type 00, seq 001497, ts 2650234352, len 000160)
Sent RTP packet to **.***.***.***:33072 (type 00, seq 001498, ts 2650234512, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018532, ts 723326308, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018533, ts 723326468, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018534, ts 723326628, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018535, ts 723326788, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018536, ts 723326948, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018537, ts 723327108, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001499, ts 2650234672, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001500, ts 2650234832, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018538, ts 723327268, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001501, ts 2650234992, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018539, ts 723327428, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001502, ts 2650235152, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018540, ts 723327588, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001503, ts 2650235312, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018541, ts 723327748, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001504, ts 2650235472, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018542, ts 723327908, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001505, ts 2650235632, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018543, ts 723328068, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001506, ts 2650235792, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018544, ts 723328228, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001507, ts 2650235952, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001508, ts 2650236112, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001509, ts 2650236272, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018547, ts 723328708, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001510, ts 2650236432, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018548, ts 723328868, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001511, ts 2650236592, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018549, ts 723329028, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001512, ts 2650236752, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018550, ts 723329188, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001513, ts 2650236912, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001514, ts 2650237072, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018552, ts 723329508, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001515, ts 2650237232, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018553, ts 723329668, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001516, ts 2650237392, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018554, ts 723329828, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001517, ts 2650237552, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018555, ts 723329988, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001518, ts 2650237712, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018556, ts 723330148, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001519, ts 2650237872, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018557, ts 723330308, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001520, ts 2650238032, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018558, ts 723330468, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001521, ts 2650238192, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018559, ts 723330628, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001522, ts 2650238352, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018560, ts 723330788, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001523, ts 2650238512, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018561, ts 723330948, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001524, ts 2650238672, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018562, ts 723331108, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001525, ts 2650238832, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018563, ts 723331268, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001526, ts 2650238992, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001527, ts 2650239152, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001528, ts 2650239312, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018566, ts 723331748, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001529, ts 2650239472, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018567, ts 723331908, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001530, ts 2650239632, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018568, ts 723332068, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001531, ts 2650239792, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018569, ts 723332228, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001532, ts 2650239952, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018570, ts 723332388, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001533, ts 2650240112, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018571, ts 723332548, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001534, ts 2650240272, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018572, ts 723332708, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001535, ts 2650240432, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018573, ts 723332868, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001536, ts 2650240592, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018574, ts 723333028, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001537, ts 2650240752, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001538, ts 2650240912, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001539, ts 2650241072, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001540, ts 2650241232, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001541, ts 2650241392, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001542, ts 2650241552, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018578, ts 723333668, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018579, ts 723333828, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018580, ts 723333988, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018581, ts 723334148, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001543, ts 2650241712, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001544, ts 2650241872, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018582, ts 723334308, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001545, ts 2650242032, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018583, ts 723334468, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001546, ts 2650242192, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001547, ts 2650242352, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018585, ts 723334788, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001548, ts 2650242512, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018586, ts 723334948, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001549, ts 2650242672, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018587, ts 723335108, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001550, ts 2650242832, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018588, ts 723335268, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001551, ts 2650242992, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018589, ts 723335428, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001552, ts 2650243152, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018590, ts 723335588, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001553, ts 2650243312, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018591, ts 723335748, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001554, ts 2650243472, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018592, ts 723335908, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001555, ts 2650243632, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018593, ts 723336068, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001556, ts 2650243792, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001557, ts 2650243952, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018595, ts 723336388, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001558, ts 2650244112, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018596, ts 723336548, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001559, ts 2650244272, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018597, ts 723336708, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001560, ts 2650244432, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018598, ts 723336868, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001561, ts 2650244592, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018599, ts 723337028, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001562, ts 2650244752, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001563, ts 2650244912, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018601, ts 723337348, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001564, ts 2650245072, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018602, ts 723337508, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001565, ts 2650245232, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018603, ts 723337668, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001566, ts 2650245392, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018604, ts 723337828, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001567, ts 2650245552, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018605, ts 723337988, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001568, ts 2650245712, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018606, ts 723338148, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001569, ts 2650245872, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018607, ts 723338308, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001570, ts 2650246032, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018608, ts 723338468, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001571, ts 2650246192, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018609, ts 723338628, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001572, ts 2650246352, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018610, ts 723338788, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001573, ts 2650246512, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018611, ts 723338948, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001574, ts 2650246672, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018612, ts 723339108, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001575, ts 2650246832, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018613, ts 723339268, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018614, ts 723339428, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001576, ts 2650246992, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001577, ts 2650247152, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018615, ts 723339588, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001578, ts 2650247312, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018616, ts 723339748, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001579, ts 2650247472, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001580, ts 2650247632, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018618, ts 723340068, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001581, ts 2650247792, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018619, ts 723340228, len 000160)
Sent RTP packet to **.***.**.***:31891 (type 00, seq 001582, ts 2650247952, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018620, ts 723340388, len 000160)
-- Stopped music on hold on SIP/6946-00002331
Got RTP packet from **.***.**.***:31891 (type 00, seq 018621, ts 723340548, len 000160)
Sent RTP packet to 192.168.1.16:54242 (type 00, seq 023196, ts 723340544, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018622, ts 723340708, len 000160)
Sent RTP packet to 192.168.1.16:54242 (type 00, seq 023197, ts 723340704, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018623, ts 723340868, len 000160)
Sent RTP packet to 192.168.1.16:54242 (type 00, seq 023198, ts 723340864, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018624, ts 723341028, len 000160)
Sent RTP packet to 192.168.1.16:54242 (type 00, seq 023199, ts 723341024, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018625, ts 723341188, len 000160)
Sent RTP packet to 192.168.1.16:54242 (type 00, seq 023200, ts 723341184, len 000160)
Got RTP packet from **.***.**.***:31891 (type 00, seq 018626, ts 723341348, len 000160)
Sent RTP packet to 192.168.1.16:54242 (type 00, seq 023201, ts 723341344, len 000160)
-- Channel SIP/7000-00002330 left 'native_rtp' basic-bridge <bdbd4521-abd3-4ed1-992e-c50424310e54>
== Spawn extension (default, 6946, 1) exited non-zero on 'SIP/7000-00002330'
-- Channel SIP/6946-00002331 left 'native_rtp' basic-bridge <bdbd4521-abd3-4ed1-992e-c50424310e54>
I connected to the server (I’m 7000) and I called another number (6946). The RTP packets appear when I start the parked call. But after, and I don’t know why, there’s 192.168.1.16.
I don’t know what’s really happening… 
I forgot to mention that I don’t have a SIP phone number.