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Pass through SBC RTP from any source?

We are using CUBE on ASR 1001-x.

When SBC sets up a call (standard INVITE sequence), a specific Media address is negotiated on the internal side (i.r. end device's media address/port communicated in m= line in SDP Offer). However, we need to send additional RTP stream from a different device where Source IP spoofing is not feasible.


The problem is that CUBE does not allow that "side" RTP stream to pass through.


Per available documentation it appears that there is no way to configure it. See esp: RTP Source Validation in IOS and IOS-XE Voice Routers - Cisco


Question: does anyone know of a way to configure IOS-XE device to pass RTP stream for a call where the source IP address does not match what was negotiated via SDP Offer?

Roger Kallberg
VIP Mentor

It would help if you could describe the use case you have so that we can understand what your trying to accomplish.

Response Signature

OK, here's a little diagram:

Internal End Device (IED) <==>SBC<==>External SBCs/GWs/Networks<===>External End Device (EED)


EED accepts only 1 m= line in SDP (which is one part of the problem). Once the call is setup, IED and EED exchange the main RTP media stream. However, in some cases, an additional media stream must be delivered to EED at the beginning of the call (right after the INVITE sequence). This additional RTP media stream cannot be sourced in IED. So we have to send it through SBC but source it outside of IED, which means that we have to fake the source IP address, but that is not feasible. We would prefer if CUBE could accept 2 RTP streams from 2 different source IPs destined to its address/port for the call and pass them (the two streams happen sequentially) onto the external network.

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