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Bug #2635

RTPC received from sysmoBTS from unexpected port

Added by neels 13 days ago. Updated 13 days ago.

Status:
New
Priority:
Normal
Assignee:
Target version:
-
Start date:
11/11/2017
Due date:
% Done:

0%

Spec Reference:

Description

Typically, an OsmoBTS sends RTPC one port next to RTP, for example the voice stream comes from port 1234, where the RTPC Sender Report packets come from port 1235.

When I set up OsmoBSC with its own OsmoMGW, I notice that both call legs consistently send the sender reports from unexpected ports. For example, here the RTP streams come from ports 33869 and 56820, while the RTPC come from 54110 and 52268:

<0000> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_network.c:850 endpoint:22 data from wrong source port: 54110, expected: 33869 for RTP or 33870 for RTCP
<0000> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_network.c:855 endpoint:22 packet tossed
<0000> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_network.c:850 endpoint:21 data from wrong source port: 52268, expected: 56820 for RTP or 56821 for RTCP
<0000> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_network.c:855 endpoint:21 packet tossed
<0000> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_network.c:850 endpoint:22 data from wrong source port: 54110, expected: 33869 for RTP or 33870 for RTCP
<0000> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_network.c:855 endpoint:22 packet tossed
<0000> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_network.c:850 endpoint:21 data from wrong source port: 52268, expected: 56820 for RTP or 56821 for RTCP
<0000> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_network.c:855 endpoint:21 packet tossed
<0000> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_network.c:850 endpoint:22 data from wrong source port: 54110, expected: 33869 for RTP or 33870 for RTCP
<0000> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_network.c:855 endpoint:22 packet tossed
<0000> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_network.c:850 endpoint:21 data from wrong source port: 52268, expected: 56820 for RTP or 56821 for RTCP
<0000> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_network.c:855 endpoint:21 packet tossed

I am not familiar enough to understand how this can happen. Does the OsmoBSC fail to tell the BTS which ports to use? Have we broken OsmoBTS recently to disregard the RTPC port constraint?

The voice call works well, only the Sender Reports are all discarded instead of forwarded.

Can you find out what causes this / whether this is expected / ...

rtpc_ports.pcapng (446 KB) neels, 11/11/2017 02:39 AM

History

#1 Updated by neels 13 days ago

attached pcap had this log output in osmo-mgw:

<0011> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_protocol.c:454 CRCX: creating new connection ...
<0011> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_protocol.c:79 endpoint:21 RTP-setup: Endpoint is in loopback mode, stopping here!
<0000> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_network.c:188 endpoint:21 Failed to send dummy RTP packet.
<0011> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_protocol.c:680 CRCX: endpoint:21 connection successfully created
<0011> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_protocol.c:704 MDCX: modifying existing connection ...
<0011> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_sdp.c:333 Got media info via SDP: port 46720, payload 255 (unknown), duration 20, addr 192.168.0.125
<0011> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_protocol.c:833 MDCX: endpoint:21 connection successfully modified
<0011> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_protocol.c:454 CRCX: creating new connection ...
<0011> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_sdp.c:333 Got media info via SDP: port 4002, payload 255 (unknown), duration 20, addr 192.168.0.5
<0011> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_protocol.c:680 CRCX: endpoint:21 connection successfully created
<0011> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_protocol.c:454 CRCX: creating new connection ...
<0011> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_protocol.c:79 endpoint:22 RTP-setup: Endpoint is in loopback mode, stopping here!
<0000> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_network.c:188 endpoint:22 Failed to send dummy RTP packet.
<0011> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_protocol.c:680 CRCX: endpoint:22 connection successfully created
<0011> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_protocol.c:704 MDCX: modifying existing connection ...
<0011> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_sdp.c:333 Got media info via SDP: port 55697, payload 255 (unknown), duration 20, addr 192.168.0.125
<0011> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_protocol.c:833 MDCX: endpoint:22 connection successfully modified
<0011> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_protocol.c:454 CRCX: creating new connection ...
<0011> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_sdp.c:333 Got media info via SDP: port 4004, payload 255 (unknown), duration 20, addr 192.168.0.5
<0011> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_protocol.c:680 CRCX: endpoint:22 connection successfully created
<0000> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_network.c:850 endpoint:21 data from wrong source port: 53981, expected: 46720 for RTP or 46721 for RTCP
<0000> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_network.c:855 endpoint:21 packet tossed
<0000> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_network.c:539 endpoint:22 SSRC changed: 2365502126 -> 344348907  from 192.168.0.5:4004
<0000> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_network.c:539 endpoint:21 SSRC changed: 3948447252 -> 2930966156  from 192.168.0.5:4002
<0000> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_network.c:850 endpoint:22 data from wrong source port: 42485, expected: 55697 for RTP or 55698 for RTCP
<0000> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_network.c:855 endpoint:22 packet tossed
<0000> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_network.c:850 endpoint:21 data from wrong source port: 53981, expected: 46720 for RTP or 46721 for RTCP
<0000> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_network.c:855 endpoint:21 packet tossed
<0011> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_protocol.c:861 DLCX: endpoint:21 deleting connection ...
<0011> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_protocol.c:925 DLCX: endpoint:21 missing ci (connectionIdentifier), will remove all connections at once
<0011> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_protocol.c:861 DLCX: endpoint:22 deleting connection ...
<0011> ../../../../src/osmo-mgw/src/libosmo-mgcp/mgcp_protocol.c:925 DLCX: endpoint:22 missing ci (connectionIdentifier), will remove all connections at once

#2 Updated by neels 13 days ago

  • Description updated (diff)

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