The SBC Core provides a wide range of high density digital signal processor (DSP) modules and a comprehensive set of converged, voice, video, vocoder, fax and data media processing functions. This section provides guidance regarding when it is necessary to use DSPs on SBC 5000 series devices (5100, 5110, 5200, 5210) and the SBC 7000 device according to protocol usage.
Applications/Features Requiring DSPs
DSPs are required for the following features. For licensing details, refer to "SBC Protocol Licenses" section on the page Managing SBC Licenses.
DSPs are needed when applying codec interworking. Below are but a few examples.
See Supported Codecs and Transcoding for codec details.
|Fax and Modem Tone detections|
Fax or Modem Tone detection can trigger modifications to calls in following scenarios, for example.
These modifications can also be triggered via re-INVITEs triggered by remote Gateways that detect the tones.
|Interworking in-band DTMF to Out-Of-Band (OOB) or RFC 2833/4733 DTMF events|
Detecting in-band DTMF for dial string applications
|When the basic codec is the same on both legs|
DSPs are needed for:
Playing compressed announcements
|Packet Service Profile option 'transcode only'||DSPs are needed when PSP Packet To Packet Control object is set to 'Transcode only'.|
The term "pass-through" refers to the case when the SBC relays the media end-to-end and no DSPs are used.
Applications/Features not Requiring DSPs
DSPs are not required for the following features:
- RFC 2833/4733 to OOB interworking
- RTCP (although RTCP termination is only recommended for transcoded calls)
- Media policing
- Signaling (Call and Registration) traffic policing
- NAT traversal including ICE
- RFC 2833/4733 based dial string applications
- G.711 announcements