sundance-communications.com/forum Forums TDM Business Telephone Systems Samsung Telephones & Systems Samsung 7100 and MPS use

I have run across a problem with one SIP carrier that we get one way audio with MPS on yet I have two other carriers MPS/MGI works great with no port forwarding of the 40000 range.
When we turn off MPS and just use MGI(30000 range) it works just fine. Again no port forwarding is in use.
This is a 7100 with NO OAS in it. Just the 6 MGI on the MP which with IP phones limits us to 3 calls of course.
We would like to use the MPS with this carrier and save the customer the cost of buying an OAS when the system already has enough resources if MPS can be used.
I have tried Private only and Private with public and it made no difference.

Do we need to set up a port forward of the MPS range to the MP even though they originate from the IP of the MP?

I always do the port forwarding, dont forget the rtg 45000 range along with mps and mgi.

Also look for sip alg (aka sip helper or sip nat helper) in the router and turn it off

I'd like to see a Wireshark trace, as I've had carriers ignore the port change from rtg to mps that the system sends in the past.

SIP ALG off and consistent nat on. Same setup on all three carriers on the Firewall. We have 50+ using Sip trunks. Network guys here know the routine on that.


So do you port forward them to the Carrier? The ports originate from the system and it comes back from the carrier on something else.

I will pull a trace tomorrow(hopefully, might be Monday). The last one I did the header looked right leaving but the RTP never got back to us.

Yes, you port forward it all to the MP card's ip address. This way it will go to the correct source.

Thanks for your help! Will take a stab at it tomorrow.

The sip messages are what I want to look at.

Basically the system and sip carrier negotiate the ports and protocol used for the call.

If you have only mgi then it will only use the 30000 range.

If you have mps enabled then the ring back tone uses 45000 , the speech uses 40000. The system sends a re-invite message to the carrier telling it to now use 40000 for the speech.

Hy, i have the same issue with a SBC, with MPS no Audio without works fine. The Port ranges for MPS i have customize to MPS 30128 and RTG 30257, also no Audio.
The SBC use the Range 30.xxx so i Try the change port range without any Audio.

Is MPS a general issue for external use with SIP Gateways and SBC

Is the sbc local or remote?
It sounds like a port forwarding issue.
Mps uses 4 ports per channel, mgi is 2, i think the rtg is also 2.
There are upto 8 of each on the 7100.
Mps ports in your case 30128-30159, Rtg 30357-30372
These need to be fiwarded to the mp10a.

A wireshark trace will confirm if the sbc is honouring the port change on the invite packet from the os7100.

Hy, thank you for the fast answer.
Its a local only communication, without any NAT and no Packet Filter. Its ony routed, the SBC inside a isolated IPv4 subnet.
I can create a new Wireshark dump, currently its working without MPS.

In that case it sounds like the sbc isn't honouring the media change.
You can try adding the ip of the sbc into mmc838.