Cisco UCCX UCCE Finesse Agent with No VPN

December 9, 2020 in Desktop Agent
Cisco UCCX UCCE Finesse Agent with No VPN

Many call centers are looking for the flexibility to operate remotely with their home-based agents and switch between office setup and remote work. Comstice offers a desktop and mobile app for Cisco Finesse in UCCX and UCCE/PCCE which includes a built-in WebRTC Softphone. This solution eliminates any VPN or specialist firewall requirements and help agents to switch between Cisco phone and Comstice softphone on the desktop and mobile.

There is no Cisco Jabber or Expressway required for this solution. Comstice Desktop Softphone does not require any installation; you can download and run. Learn more.


Comstice Softphone for the Desktop is a click and run app which does not require any installation on the PC. Learn more.

Comstice Softphone app for Mobile and Tablets can be downloaded from Apple AppStore and Google Play Store. Please search for Comstice Mobile Agent, download and run it in demo mode. Learn more.

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Topology for Cisco Finesse with no VPN

Topology for Cisco Finesse with no VPN

Comstice provides WebRTC Gateway and SIP B2BUA for desktop and mobile softphones to communicate with Cisco Finesse and Cisco CUCM. WebRTC Gateway is often hosted in the DMZ and SIP B2BUA Server is hosted in the internal network.

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Comstice WebRTC Gateway

Comstice built-in softphone is a third-party device created by Comstice which utilises HTTPS for signaling and secure RTP for the audio and video calls. WebRTC gateway terminates webrtc sessions coming from the Comstice desktop and mobile softphone clients and registers these sessions as third-party SIP phones on Comstice SIP B2BUA. Comstice SIP B2BUA communicates with Cisco CUCM via SIP trunk.

Technically, Comstice WebRTC sessions can register directly with Cisco CUCM as third-party SIP Phones. However, since Cisco Cisco UCCE and UCCX require these third-party devices to be outside Cisco CUCM, Comstice SIP B2BUA is used.

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Comstice WebRTC Gateway also acts as a Web Proxy for Cisco Finesse communications. It uses HTTPS and XMPP and proxies Cisco Finesse signaling so that there is no need to open Cisco UCCX directly to public Internet.

Audio Recording

As an option, Comstice WebRTC Gateway records audio sessions for compliance, in case there is any continuous recording requirement.

More information about WebRTC standard can be found by clicking here.

WebRTC signaling is through HTTPS and the audio is through secure RTP. Using a NAT configuration on your firewall, you can allow audio communication with Cisco CUCM and Comstice WebRTC softphones.

Comstice SIP B2BUA Server

Comstice SIP B2BUA registers all the active WebRTC sessions as SIP Phones and also communicates with Cisco CUCM via SIP trunk. This service does not pass through any RTP session and used purely for signaling.

Cisco Finesse Softphone Inbound Call Flow

Cisco Finesse Softphone Inbound Call Flow Image

Cisco UCCX

  1. CTI Remote Device is created on Cisco CUCM to simulate a Cisco Phone for the Cisco UCCX Agent. Remote destination is set as the extension number of the WebRTC softphone.
  2. Agent logs in to Cisco UCCX using Comstice Desktop or Mobile Softphone with the same agentID but with the extension of the CTI Remote Device. Agent can switch between her Cisco deskphone or CTI Remote Device for Cisco Finesse using Comstice Handoff Service.
  3. When agent is picked, customer call is sent to Comstice B2BUA via SIP Trunk and it sends the call to WebRTC softphone running on Comstice Desktop or Mobile App
  4. There are two RTP sessions; an sRTP session between Comstice WebRTC Gateway and Comstice Softphone and RTP session between Cisco Voice Gateway and Comstice WebRTC Gateway.

Cisco UCCE / PCCE

  1. Cisco CUCM LCP and RCP ports are created for UCCE Mobile Agent feeature. Agent logs in using LCP port extesion. Call-by-call is enabled by default and remote softphone extension is retrieved from Comstice WebRTC Server.
  2. Agent logs in to Cisco UCCX using Comstice Desktop or Mobile Softphone with the same agentID but with the extension of the LCP port. Agent can switch between her Cisco deskphone or Comstice Desktop / Mobile Softphone simply by swapping the extension during login.
  3. When agent is picked by UCCE, customer call is sent to remote destination which is the SIP extension of the WebRTC Softphone. Call is sent to Comstice B2BUA Servere via SIP Trunk and it sends the call to WebRTC softphone running on Comstice Desktop or Mobile App via WebRTC Gateway.
  4. There are two RTP sessions; an sRTP session between Comstice WebRTC Gateway and Comstice Softphone and RTP session between Cisco Voice Gateway and Comstice WebRTC Gateway.

Cisco Finesse Softphone Transfer Call Flow

Cisco Finesse Softphone Transfer Call Flow Image

Cisco UCCX

  1. During an active call, Comstice softphone can request transfer, consult or conference.
  2. WebRTC Softphone, not Cisco Finesse will start the transfer in UCCX model.
  3. The call is then routed to the new destination via Comstice SIP B2BUA Server, Cisco CUCM and voice gateways.

Cisco UCCE / PCCE

  1. During an active call, Comstice softphone can request transfer, consult or conference.
  2. Cisco Finesse will manage the request and transfer the call by creating a new call leg and terminating the existing call leg to agent's destination device.
  3. The call is then routed to the new destination via Comstice SIP B2BUA Server, Cisco CUCM and voice gateways.

Cisco Finesse Softphone Outbound Call Flow

Cisco Finesse Softphone Outbound Call Flow Image

Cisco UCCX

  1. Comstice softphone sends an outbound call request to Comstice SIP B2BUA.
  2. The request is sent through SIP trunk to Cisco CUCM and internal or external destination is connected.

Cisco UCCE / PCCE

  1. Comstice softphone sends an outbound call request to Cisco Finesse.
  2. Cisco Finesse will manage the request, will ask CUCM to create two call legs. One to the destination and one to the agent's softphone.
  3. In this scenario, agent will in fact receive a call to her Comstice softphone.

Comstice Desktop and Mobile Softphone with Third-party Phone Line

Comstice Desktop and Mobile Softphone with Third-party Phone Line Image

If the Internet connectivity is not good for the reliable audio conversations, agents can also switch to home phone or cell phone line.

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Mobile agents may prefer to switch to cell phone line for better audio quality while they are on the move.

High Availability

Comstice WebRTC Gateway and Comstice SIP B2BUA Flow Image

Both Comstice WebRTC Gateway and Comstice SIP B2BUA can run on active:active mode. The solution is tolerant to high latency between the DR sites. If WebRTC Service running on the WebRTC Server is lost, the call drops. In any other scenarios, active call is preserved as long as the network path is still available.

Comstice is a Cisco Solution Partner specialising contact center technologies and omnichannel customer service.

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