topic Re: Is ECCP-like functionality possible with Webex Calling? in Webex for Developers

Is ECCP-like functionality possible with Webex Calling?

kristjan — Fri, 06 Jun 2025 05:00:25 GMT

Hi everyone,

I'm currently working on migrating our telephony system from Cisco CUCM to Webex Calling. Our current setup relies heavily on CUCM's ability to send an ECCP (External Call Control Protocol) request to our system, wait for a response, and then continue call routing based on that response.

As I understand it, Webex Calling doesn’t support ECCP directly. So I’ve been looking for a similar mechanism that could allow our system to influence or control call routing in a comparable way.

So far, I’ve considered a couple of alternatives:

Using Webhooks + Webex Calling APIs: Our system would listen for Webex Calling events (like an incoming call), run its own logic (which mimics the ECCP decision-making), and then use the Webex Calling API to take appropriate actions (e.g., redirect the call, reject it, etc.).
System-Initiated Calls: Instead of waiting for Webex to notify us, our system would initiate outbound calls and execute the ECCP-like logic before dialing. This would give us full control, but might require a shift in how we handle call flows.

My questions:

Is there a native or recommended way to implement ECCP-like behavior in Webex Calling?
If not, what’s the most viable workaround for systems that need to intercept and approve/reject calls based on external logic?

Any advice or pointers would be greatly appreciated. I’m still trying to fully understand Webex Calling’s capabilities, so apologies if I’ve misunderstood any part of the architecture.

Thanks in advance!

Re: Is ECCP-like functionality possible with Webex Calling?

Janos Benyovszki — Tue, 10 Jun 2025 13:52:15 GMT

@kristjan the Call Control we have on the Webex Calling API side is internal, not external, as you noticed https://developer.webex.com/calling/docs/api/v1/call-controls .

Although I am not entirely familiar with ECCP, I think your first approach with Webhooks and API might work. We have a list of supported Calling Webhooks here https://developer.webex.com/calling/docs/api/guides/webhooks#filtering-webhooks (anything with telelephony_* ) . The Call Control API was already mentioned above.

Re: Is ECCP-like functionality possible with Webex Calling?

Ciscollab_Amit — Tue, 10 Jun 2025 19:05:22 GMT

If Webex Calling Dedicated Instance is an option, then why not setup the dedicated instance, utilise native ECCP functionality and then route the calls to WxC?

Just another option that came Ad-hoc in my mind.

Regards,

Amit

Re: Is ECCP-like functionality possible with Webex Calling?

kristjan — Fri, 13 Jun 2025 05:00:23 GMT

Thank you for the idea, but I think that using Webhooks is the best for our use case. We'll start working on that, but keep this in mind as a back up.

Re: Is ECCP-like functionality possible with Webex Calling?

kristjan — Fri, 13 Jun 2025 05:01:37 GMT

Thank you for the reply. Yeah, we're going with this route, we'll start working on implementing this, and I'll come back to report how it went.

Re: Is ECCP-like functionality possible with Webex Calling?

kristjan — Mon, 15 Sep 2025 05:14:14 GMT

So a quick follow-up:
We attempted to replicate the ECCP functionality in Webex Calling by using Webhooks in combination with the Call Control API. The main challenge turned out to be the timing of when a call is actually created.

With ECCP in CUCM, a call does not begin until the external server returns its response. For example, if the server responds with “block this call,” CUCM never initiates the call in the first place.

In Webex Calling, however, there is no equivalent ECCP feature. When user A calls user B, the call is initiated immediately, and only then does Webex generate webhook events for subscribed listeners. These listeners can process the event and issue an action via the Call Control API. Because this involves some delay, it is possible for a call to appear active for a few seconds before the API action (e.g., block) takes effect.

So in summary, we found that real-time call control before call setup isn’t currently achievable in Webex Calling with the available APIs.