For s SIP to SIP call flow, when does Cisco Unified Border Element require transcoding resources for DTMF?
Click on the arrows to vote for the correct answer
A. B. C. D.A.
https://www.cisco.com/c/en/us/support/docs/unified-communications/unified-border-element/200412-DTMF-Relay-and-Interworking-on-When a SIP-to-SIP call flow is established, Cisco Unified Border Element (CUBE) may require transcoding resources for DTMF (Dual Tone Multi-Frequency) interworking. DTMF is used to send input signals such as key presses during a call, and it is important that these signals are correctly transmitted and received by both endpoints.
In SIP-to-SIP call flows, DTMF interworking can be achieved through various methods, such as in-band audio, out-of-band (OOB) signaling, or using specific RTP (Real-time Transport Protocol) payloads. Depending on the method used, different interworking mechanisms may be required to ensure proper DTMF transmission.
The options presented in the question refer to different interworking scenarios between various DTMF signaling methods.
Option A mentions interworking between an OOB method (such as SIP INFO) and RFC2833 for flow-around calls. In flow-around calls, the CUBE allows the media stream to flow directly between the endpoints without going through the CUBE itself. In this scenario, if the endpoints are using different DTMF signaling methods (such as one using OOB and the other using RFC2833), the CUBE may need to transcode the DTMF signals in order to ensure proper transmission.
Option B refers to interworking between h245-signal and rtp-nte. H245-signal is a signaling protocol used in H.323 call flows, while rtp-nte is an RTP payload type used for DTMF signaling. In SIP-to-SIP call flows, if one endpoint is using H.323 and the other is using SIP, the CUBE may need to translate the DTMF signals between the two different signaling methods.
Option C mentions interworking between an OOB method and RFC2833 for flow-through calls. In flow-through calls, the media stream is processed by the CUBE before being sent to the other endpoint. In this scenario, if the endpoints are using different DTMF signaling methods, the CUBE may need to transcode the DTMF signals to ensure proper transmission.
Option D refers to interworking between h245-alpha numeric and sip-kpml. H245-alpha numeric is another signaling protocol used in H.323 call flows, while sip-kpml is a signaling method used in SIP-to-SIP call flows. As with option B, if one endpoint is using H.323 and the other is using SIP, the CUBE may need to translate the DTMF signals between the two different signaling methods.
In summary, the correct answer to the question is option A, interworking between an OOB method and RFC2833 for flow-around calls. In this scenario, the CUBE may need to transcode the DTMF signals to ensure proper transmission between endpoints using different DTMF signaling methods.