Bug #2874: MGCP originates not from IETF standard port 2427 - OsmoMSC - Open Source Mobile Communications

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Bug #2874

closed

MGCP originates not from IETF standard port 2427

Added by laforge over 6 years ago. Updated over 5 years ago.

Status:

Resolved

Priority:

Low

Assignee:

dexter

Category:

Target version:

Start date:

01/25/2018

Due date:

% Done:

100%

Resolution:

Spec Reference:

Description

RFC 3435 states that a call agent has a default port of 2427, but we appear to be sending MGCP from a random source port.

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Updated by laforge almost 6 years ago

Assignee set to dexter

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Updated by dexter almost 6 years ago

From what I can see this problem would be easy to fix by just setting #define MGCP_CLIENT_LOCAL_PORT_DEFAULT 0 to 2427, but then we can never run the mgw on the same host which holds the call agent. We then need to separate those two by the ip-addresses. I think that would brake a lot of things.

Also the VTY has a way to configure the local port to a fixed value (mgw local-port <0-65535>). I think we should leave it as it is since if this spec violation turns out to be a real world problem, then one could always set the port to fix it.

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Updated by laforge almost 6 years ago

On Wed, Jul 25, 2018 at 10:25:40AM +0000, dexter [REDMINE] wrote:

From what I can see this problem would be easy to fix by just setting
#define MGCP_CLIENT_LOCAL_PORT_DEFAULT 0 to 2427, but then we can
never run the mgw on the same host which holds the call agent.

Why? MGCP specifies a different port number for Call Agent and MGW. So
a single CA and a single MGW on a given machine/IP is not a problem.

The problem would only start if you want to run multiple Call Agents on
the same machine/IP, such as OsmoBSC + OsmoMSC.

Also the VTY has a way to configure the local port to a fixed value (mgw local-port <0-65535>). I think we should leave it as it is since if this spec violation turns out to be a real world problem, then one could always set the port to fix it.

I think the big problem here is that for at least half, if not almost an
entire year we still don't have an osmo-mgw manual or any other
documentation that would actually mean users can find this setting
easily.

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Updated by dexter almost 6 years ago

Status changed from New to In Progress
% Done changed from 0 to 100

I looked it up, its actually 2727, thats why I was confused. I have now set 2727 as default port.

https://gerrit.osmocom.org/#/c/osmo-mgw/+/10188 mgcp_client: use IETF source port as for MGCP

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Updated by dexter almost 6 years ago

To relax the possible problem of port collisions when BSC and MSC run on the same machine I updated the default configs so that if the default configs are used the ports are not clashing.

https://gerrit.osmocom.org/#/c/osmo-bsc/+/10239 doc: update mgw settings in example config file
https://gerrit.osmocom.org/#/c/osmo-msc/+/10240 doc: update mgw settings in example config file

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Updated by dexter over 5 years ago

To me this problem seems to be resolved. We now should decide if we want to upgrade the example configuration of osmo-bsc and osmo-msc. I don't think this is really necessary.

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