MGW MGCP Issues - OpenBSC

8 Dec 2017


      Hello,
we are trying to setup a splitted gsm 2g network, all services are on
different vm's,
e.g. one machine for bsc ,one for bts ...!
At all we have 6 different vm's on a local subnet 192.168.192.X:
osmo-bts-trx (IP = .12) with osmo-trx to support N210 (192.168.10.6) with
TRX IP 127.0.0.1
osmo-bsc - IP = .41
osmo-msc - IP = .42
osmo-hlr IP= .43
osmo-stp IP = .44
and also osmo-mgw (IP=.45) with 2 instances, one for osmo-bsc and the other
for osmo-msc.
If I'm try to call from mobile a to mobile b, I able to see that the call
is incoming but a connection  won't establish, the other mobile is ringing,
if I pick up the call on mobile b, mobile a is still trying to connect.
On osmo-bts-trx I get some errors:
<000e> l1sap.c:96 RTP clock out of sync with lower layer: 320 vs 160
(1937437->1937446)
<000e> l1sap.c:96 RTP clock out of sync with lower layer: 0 vs 160
(1937446->1937446)
On osmo-mgw at bsc-side the output looks like:
<0011> mgcp_protocol.c:453 CRCX: creating new connection ...
<0011> mgcp_protocol.c:79 endpoint:15 RTP-setup: Endpoint is in loopback
mode, stopping here!
<0000> mgcp_network.c:188 endpoint:0x15 Failed to send dummy RTP packet.
<0011> mgcp_protocol.c:653 CRCX: endpoint:0x15 connection successfully
created
<0011> mgcp_protocol.c:676 MDCX: modifying existing connection ...
<0011> mgcp_sdp.c:333 Got media info via SDP: port 26360, payload 255
(unknown), duration 20, addr 192.168.192.12
<0011> mgcp_protocol.c:805 MDCX: endpoint:0x15 connection successfully
modified
<0011> mgcp_protocol.c:453 CRCX: creating new connection ...
<0011> mgcp_sdp.c:333 Got media info via SDP: port 4002, payload 255
(unknown), duration 20, addr 192.168.192.45
<0011> mgcp_protocol.c:653 CRCX: endpoint:0x15 connection successfully
created
<0011> mgcp_protocol.c:453 CRCX: creating new connection ...
<0011> mgcp_protocol.c:79 endpoint:16 RTP-setup: Endpoint is in loopback
mode, stopping here!
<0000> mgcp_network.c:188 endpoint:0x16 Failed to send dummy RTP packet.
<0011> mgcp_protocol.c:653 CRCX: endpoint:0x16 connection successfully
created
<0011> mgcp_protocol.c:676 MDCX: modifying existing connection ...
<0011> mgcp_sdp.c:333 Got media info via SDP: port 64810, payload 255
(unknown), duration 20, addr 192.168.192.12
<0011> mgcp_protocol.c:805 MDCX: endpoint:0x16 connection successfully
modified
<0011> mgcp_protocol.c:453 CRCX: creating new connection ...
<0011> mgcp_sdp.c:333 Got media info via SDP: port 4004, payload 255
(unknown), duration 20, addr 192.168.192.45
<0011> mgcp_protocol.c:653 CRCX: endpoint:0x16 connection successfully
created
However, the osmo-mgw msc side reports following:
<0011> mgcp_protocol.c:453 CRCX: creating new connection ...
<0011> mgcp_protocol.c:79 endpoint:1 RTP-setup: Endpoint is in loopback
mode, stopping here!
<0000> mgcp_network.c:188 endpoint:0x1 Failed to send dummy RTP packet.
<0011> mgcp_protocol.c:653 CRCX: endpoint:0x1 connection successfully
created
<0011> mgcp_protocol.c:453 CRCX: creating new connection ...
<0011> mgcp_protocol.c:79 endpoint:2 RTP-setup: Endpoint is in loopback
mode, stopping here!
<0000> mgcp_network.c:188 endpoint:0x2 Failed to send dummy RTP packet.
<0011> mgcp_protocol.c:653 CRCX: endpoint:0x2 connection successfully
created
Best Regards
Sebastian