Single Number Reach

[j.huizinga]

Hi

We have a customer where we have configured SNR to MS-teams, and this works.

What we want is encryption between CUCM and the CUBE that connects to MS-teams. And this we can't get this to work

To configure encryption between CUCM and CUBE is quite straight-forward,and in general not that complicated. But with SNR we have issues.

When we dial directly from an IP phone (that is encrypted) the MS-teams number the call is encrypted end-to-end. But when an external call is calling this IP phone and SNR is executed, the call fails.

What we see in the debugs is that when the IP phone calls directly the MS-teams number in the SDP we have the a=crypto: entries.

When we call from external (CUBE with provider) the IP extension and after 4 seconds the call goes to the CUBE with MS-teams (different CUBE) but without any a=crypto: values and the call fails with 488 ("Cannot fallback to RTP. SRTP configured on dialpeer") We don't want to fall back, we want encryption

Has anyone encountered this before? I mean SNR calls not being encrypted? These SNR calls are going to MS-Teams, but this is the same I believe when trying to encrypt any SNR call when the call is initiated from external

Thank you

JH

[Scott Leport]

Hi there,

Haven't done this yet, but I have often referred to this blog in addition to Cisco's own direct routing document before carrying out direct routing deployments. This blog (I think) is close to what you're trying to achieve?
Microsoft Teams Direct Routing & Cisco CUCM Integration - IP Corp

Have you enabled srtp pass-thru in your config?

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/voice/cube/ios-xe/config/ios-xe-book/cube_m_voi-srtp-srtp-passthrough.pdf

[j.huizinga]

Thank you for your reply

The link to the blog is very useful, better actually then the Cisco documentation. And this is what I have configured

So we have end-to-end encryption when an IP phone calls the MS-Teams number, and we have encryption when MS-teams calls an IP phone.

The issue is when a call comes inside from the provider (over a separate CUBE) and calls an IP phone. When the IP phone answers, there is encryption between provider CUBE and IP phone. But when SNR is activated the call to MS-teams goes over a second CUBe and now there is no SRTP, the initial INVITE from CUCM to teams has an SDP that does not have crypto info

So basically, when using SNR can you have encryption?

[Samuel T Mathai]

Have you figured out this.. I have same issue.