Config and verify Expressway B2B encrypted to other company?

[samhopealpha]

Hi everybody, 

Background

Video endpoint ---- CUCM --- EXP-C ---(tls)--- EXP-E (CompanyA) === Internet === (CompanyB) video endpoint

Due to the scenario is connecting to other company, so
> Expressway MRA with B2B is used

Question:

My question is how do I know the path between Exp-E and CompanyB's Video Endpoint has encrypted media stream?

In my understand, encrypted connection usually required to generate CSR and apply signed cert between 2 nodes

However, I don't see the Cisco Doc has mentioned anything about the cert setting between CompanyA and CompanyB.

Or is it already encrypted between Exp-C and Exp-E, then the rest of packets are all encrypted toward CompanyB? 

Does anybody has an idea?

Thanks in advance

Sam

[mbowden7]

Hello,

You are right it is encrypted via SRTP at the beginning of CUCM.

here is Doc http://www.cisco.com/c/en/us/support/docs/unified-communications/telepresence-video-communication-server-vcs/118877-config-vcs-00.html

You can read the first few pages for answer.

[Patrick Sparkman]

If both organizations support encryption, the call will be encrypted end-to-end.  However, if something within the path doesn't support encryption, the call will not be encrypted.  In either case, the call details should tell you if it's encrypted or not.