| Asset ID: |
1-71-1597442.1 |
| Update Date: | 2018-01-04 |
| Keywords: | |
Solution Type
Technical Instruction Sure
Solution
1597442.1
:
Acme Packet: How to Debug Basic Dual-Tone Multi-Frequency Issues
| Related Items |
- Acme Packet 4500
- Net-Net 3810
- Acme Packet 3820
|
| Related Categories |
- PLA-Support>Sun Systems>CommsGBU>Session Delivery Network>SN-SND: Acme Service Provider
|
In this Document
Applies to:
Acme Packet 4500 - Version All Versions and later
Net-Net 3810 - Version All Versions and later
Acme Packet 3820 - Version All Versions and later
Acme Packet OS
Goal
How to debug basic DTMF issues.
Solution
When Dual-tone multi-frequency (DTMF) tones seemed to be lost (completely not received) by one or another side, it’s unlikely that the packet loss is the reason for this. Start by looking at the media negotiation in the SIP/H323 signaling packets. All or some messages of the call setup (Invite/Trying/Ringing/200 OK/Ack) will have SDP part that should have something similar to this:
m=audio 46090 RTP/AVP 0 8 101
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
Session Description Protocol (SDP) doesn’t really “negotiate” media parameters, but if INVITE that has “a=” with telephone-event, and the corresponding 200 OK doesn’t have it, it's likely the session won’t use RFC 2833 for DTMF tones.
Does it mean that the DTMF tones are not transferred? It depends. In case with Cisco Gateways, they will not extract DTMF tones from the audio, so the tones will come as a wave form. On the other end, if it’s a pure IP endpoint, it likely won’t have tone waveform generator, and the tones won’t be sent at all.
Set dtmfmode to inband, rfc2833, or info. DTMF digits can be sent either in band (as part of the audio stream), or out of band (as signaling information), using the RFC 2833 or INFO methods.
If on NN4200 series, either inband-inband or outband-outband will work. Outband-outband covers INFO-INFO, RFC 2833-RFC 2833.
Please refer to the Net-Net 4000 ACLI Configuration Guide, section 7 Inter-Working Function Services (IWF Services) for how to configured DTMF interworking.
If the ingress supports inband and egress does not support inband, Session Director (SD) will send DTMF inband even though egress does not support. The NN4200 series of Session Directors do not support transcoding to outband for egress (NN9200 series is required for transcoding solution).
If the ingress supports outband and egress does not support outband, SD will send INFO (outband) to egress even though egress does not support outband (NN9200 series is required for transcoding solution).
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