SIP Client : No SDP in INVITE from CUCM

[bvasquez98]

Hi All,

We are trying to interconnect the IMS of an ePC (LTE Network) in SIP client to a Cisco CUCM 12.5. Communications from a Smartphone (LTE Network) to a TOIP (behind the CUCM) work very well. When a TOIP calls a Smartphone, the call is refused by the ePC because the SIP INVITE sent by the CUCM does not contain an SDP (this is mandatory for the ePC). We can't figure out how to configure the CUCM to send SDP in its SIP INVITE. We know how to do it in SIP Trunk (SIP profile CUCM) but not in SIP Client. Can anyone guide us to achieve this?

Thanks a lot in advance!

Benjamin

[b.winter]

The same way you do it on the SIP trunk --> via the SIP profile, which you assign to the device for the sip client.

[bvasquez98]

Hi b.winter,
Thanks a lot for your response.

However, we tried all possible parameters concerning the SDP in the SIP profile. Could you tell us exactly the parameters?

[b.winter]

There is no difference between doing it for a SIP trunk and another SIP device... All SIP entities use SIP profiles.
So how did you do it for a SIP trunk then?
In the SIP profile "Early Offer support for voice and video calls" --> "Best Effort" or "Mandatory"

[bvasquez98]

Ok thanks, we'll try again. I'm not the person setting up the CUCM, my customer is doing it and I'm not sure what exactly he tried. I'll check with him and keep you informed.

[Maren Mahoney · Accepted solution]

If a picture will help, the following is on your SIP Profile. Certainly, have MTP either Mandatory or Best Effort. If you want to set it for Mandatory (insert MTP if needed) but for sure don't want CUCM to ever insert an MTP, then create a Media Resource Group List that does not have access to one.

Also include "Send send-receive SDP in mid-call INVITE" so that MoH and Conferencing will use Early Offer as well.

Depending on the integration, you may also want to enable Early Media negotiation.

My pic does not have SIP Options PING enabled, but I do recommend that if the other end of the trunk will support it.

Maren

[bvasquez98]

Good morning,

Thank you for your answers. The customer wishes to remain in Trunk to facilitate management at home (especially for routing and resilience) so we will not try the SIP Client again. Thanks again anyway.