12-01-2009 09:05 AM - last edited on 03-25-2019 07:54 PM by ciscomoderator
Hi All
As part of a large migration from TDM to IPT we have installed 3 x V224 Analogue Gateways for use with Modems on Laptops etc. to dial up to customer equipment via the PSTN (TDM).
The engineers who are initiating the modem connections are complaining that the negotiated speed is very low and is often dropping the connection or hanging the session.
I have checked both the V224 and VWIC gateways and bot are set to enable Modem Passthrough, not too sure what else I should be checking.
Any assistance on what to check would be much appreciated.
Thanks Greg
Solved! Go to Solution.
12-01-2009 10:39 AM
The VWICs, are they MFTs? PRIs? If so, are you
getting your clock form the carrier? Clock slips will cause the type
of behavior you are seeing. Do a show controller....
If you find nothing there, something in the back of my mind is telling me you might want to make sure you also have fax passthrough - that in certain cases that handles modem traffic as well
12-01-2009 09:37 AM
what protocol(s) are you running on the VGs and VWICs?
12-01-2009 10:27 AM
Hi
Thanks for the reply, using MGCP on both V224 and PSTN Gateways.
Cheers Greg
12-01-2009 10:39 AM
The VWICs, are they MFTs? PRIs? If so, are you
getting your clock form the carrier? Clock slips will cause the type
of behavior you are seeing. Do a show controller....
If you find nothing there, something in the back of my mind is telling me you might want to make sure you also have fax passthrough - that in certain cases that handles modem traffic as well
12-01-2009 11:00 AM
Greg,
Take a look here:
http://www.cisco.com/en/US/docs/ios/12_2t/12_2t11/feature/guide/ft_ghost.html#wp1072731
controller E1 0/1
pri-group timeslots 1-31 service mgcp
!
interface Serial0/0:15
no ip address
isdn switch-type primary-net5
isdn incoming-voice modem
isdn bind-l3 backhaul set1
no cdp enable
!
mgcp modem passthrough voip mode nse
mgcp modem passthrough voip codec g711alaw
mgcp codec g729r8 packetization-period 10
mgcp vad
mgcp quarantine mode process
mgcp package-capability dtmf-package
mgcp package-capability mf-package
mgcp package-capability rtp-package
mgcp package-capability nas-package
mgcp package-capability as-package
mgcp package-capability script-package
mgcp default-package ms-package
no mgcp timer receive-rtcp
no mgcp piggyback message
mgcp fax t38 inhibit
mgcp profile default
mgcp profile PRI
call-agent 10.10.0.0 service-type mgcp version 0.1
Make sure your settings match at both ends - and perosnnaly I would get rid of the VAD line. Make sure the G711 line is in there, and is properly set (alaw vs ulaw) depending on your location
HTH,
Art
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