(A URI looks like an email address. For example, I might set up a URI as dx80@joshualearn.com for folks to reach me on a Cisco DX-80. The URIs on WebEx are actually a bit longer. One might look more like dx80@joshualearn.rooms.webex.com on WebEx. Most of the time folks don't type out the URIs so that's not usually a concern.)
So what happens when you want to dial a PSTN telephone number? How do we associate a PSTN telephone number to a video device? Previously, the only option was to turn up a SIP trunk with a telco provider within the WebEx Control Hub. Then one would order new DIDs, assign a DID, and assign an internal number to a video endpoint. That process involves starting a service contract with a telco provider that has an established relationship with Cisco WebEx. Cisco has termed this type of company as a "Cisco Preferred Media Provider".
While that is still an option, some folks have asked how they can bring their own PSTN by integrating with their existing on-premises Cisco Collaboration investment. Before there was not an option. Now those folks are in luck. Utilizing what's known as Cisco WebEx Hybrid Call Service the Cloud Video environment can be married to On-Premises Calling environment.
What's involved to make that work? I'll write a follow-up post with more detail. In the meantime, here is a high-level list of what's under the hood.
- Cisco WebEx Cloud registered video endpoints
- Cisco Unified Communications Manager solution on-premises
- On-premises PSTN connectivity via a Cisco Voice Gateway or CUBE
- Cisco Expressways
- Cisco Expressway-C Services Host
- Cisco Expressway-C Traversal Host
- Cisco Expressway-E Traversal Host (with 2 NICs)
- Firewalls
- 2 firewalls are recommended, however, I have also seen it designed with 1.
- Firewall policies
- NAT
- DNS
- A records
- SRV records
- Certificates
- Internal certificates are allowable however the WebEx Control Hub needs to trust the issuing CA chain.
Part 2 of this blog series will include more of the detail on some of the specifics related to the "how-to" design and deploy the solution.
If you have tried this already, have thoughts about trying this, or just like to leave comments, please leave one below.
