I have the requirement to connect a CUCM to an ISR Router (e.g. 28xx) via a SIP Trunk.
Of course, this shouldn't be a problem.
BUT. I need to authenticate the gateway to the cucm via SIP-digest (please don't ask why :-).
On CCO I found out, that a authentification on a CUCM sip-trunk should be possible (see on: http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/security/6_1_1/secugd/secrealm.html#wp1070945)
I was wondering what has to be done on the ISR gateway. Is this possible and when yes what has to be configured??