Mediatrix 4104 DGW / SIP Fax Call Disconnects

[bribob]

I'm trying to connect a fax machine using port 1 of a Mediatrix 4104plus running Dgw 2.0.23.358 as a SIP Device to a 3300 CX2 running 11.0.1.26.

The 3300 is on a separate subnet and port 1 is registered to the 3300 via port 5060, there are no layer 3 restrictions between the two subnets. I think I've followed the 4108 SIP Device how-to from MoL (08-5159-00011), specifically allowing Voice and Data for only G.711u/a and G.729. T.38 appears to be disabled.

On the 3300, the SIP Device has the same COS and COR as a working 5330. Call Reroute 1st Alt is set to default. SIP Device Capabilities has Replace System based with Device based In-Call = YES, all other values are default.

When I place a call from the PSTN (PRI) to the registered DN, I hear ring back signal and can see the port status going 'busy'. After approximately 15 seconds, the call is answered and then disconnects after 1 second. SIP TCPDUMP confirms this.

------------------------------------------
<Some Output Omitted>
1 0.000000 <3300 IP> <4104 IP> SIP 630 Request: INVITE sip:123456@<4104 IP>
2 0.240000 <4104 IP> <3300 IP> SIP 490 Status: 180 Ringing
3 15.180000 <4104 IP> <3300 IP> SIP/SDP 841 Status: 200 OK, with session description

Message Body
v=0
o=MxSIP 1979804083125071506 1026389027111516091 IN IP4 <4104 IP>
s=-
c=IN IP4 <4104 IP>
t=0 0
a=sendrecv
m=audio 5004 RTP/AVP 0 8 101
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15

4 15.260000 <3300 IP> <4104 IP> SIP/SDP 608 Request: ACK sip:123456@<4104 IP>, with session description

Message Body
v=0
o=- 5724 5724 IN IP4 <E2T IP>
s=-
c=IN IP4 <E2T IP>
t=0 0
m=audio 50258 RTP/AVP 0 101
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15


5 16.660000 <4104 IP> <3300 IP> SIP 476 Request: BYE sip:<External CLID>@<3300 IP>:5060;transport=udp
6 16.660000 <3300 IP> <4104 IP> SIP 526 Status: 200 OK

------------------------------------------

Where to check next? Should I be concerned with the Machine Detection section under Media > Misc (CNG/CED/V.21 Modulation Detection). Does anything jump our regarding the codecs being exchanged in packets 3 and 4? Have I really disabled T.38? Is there a compatibility issue between the Dgw firmware and the MCD?

I have not had the opportunity to test if outbound voice/fax calls have the same result.

Any insight is appreciated.
-b

 

[LoopyLou]

Would plug in a analog phone and verify that functions first.

I'd tell you a UDP joke but I'm afraid you won't get it. TCP jokes are the best because you always get them.

 

[kwbMitel]

Yeah BriBob, have you tried an standard phone?

What kind of tech support are you getting anyways?

Sheesh.

**********************************************
What's most important is that you realise ... There is no spoon.

 

[bribob]

not very good support it would seem. I'll arrange to have a body connect an analog set to the port and see if the call stays up.

I shouldn't have any issues with the Firmware? Everything from the MoL doc is more or less there in Dgw 2...

 

[bribob]

After allowing the Mediatrix to rest for the weekend, fax calls are now successful. I have made no configuration changes, nor has the Mediatrix been rebooted. I can't explain why it's working now or why it wasn't working then.

On a side note, the customer had just painted their server room floor. It's a good thing this wasn't a Layer 1 problem, otherwise there would be foot prints

Thanks for the ideas LL + kwb

-b

 

[kwbMitel]

That's some crazy s**t right there

Take it easy bud, shaved yet?

**********************************************
What's most important is that you realise ... There is no spoon.