Hi Michael,
Here is some related info;
Configuring the SRTP Allowed Check Box
The SRTP Allowed check box displays in the following configuration windows in Cisco Unified Communications Manager Administration:
â¢H.323 Gateway Configuration window
â¢H.225 Trunk (Gatekeeper Controlled) Configuration window
â¢Inter-Cluster Trunk (Gatekeeper Controlled) Configuration window
â¢Inter-Cluster Trunk (Non-Gatekeeper Controlled) Configuration window
â¢SIP Trunk Configuration window
To configure the SRTP Allowed check box for H.323 gateways and gatekeeper or non-gatekeeper controlled H.323/H.245/H.225 trunks or SIP trunks, perform the following procedure:
Procedure
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Step 1 Find the gateway or trunk, as described in the Cisco Unified Communications Manager Administration Guide.
Step 2 After you open the configuration window for the gateway/trunk, check the SRTP Allowed check box.
Step 3 Click Save.
Step 4 To reset the device, click Reset.
Step 5 Verify that you configured IPSec correctly for H323. (For SIP, make sure you configured TLS correctly.)
Cisco Unified Communications Manager Security Guide, Release 7.0(1)
Configuring Encryption for Gateways and Trunks
http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/security/7_0_1/secugd/secumgcp.html#wp1055164
Hope this helps!
Rob