Part I and Part II of this blog post cover CvW fundamentals and how does it work. Now this part of the blogpost will cover CvW prerequisites and deployment process.

CvW is a cool feature of Skype for Business but it can only be configured in few scenarios. Below are the prerequisites and infrastructure should meet these requirements.

• Unified Communication Web API (UCWA): Comes default with Skype for Business Server and installed automatically on all Skype for Business Front End Servers.
  
• Mediations Server: Should be deployed standalone or part of the Front End server.
  
• Direct Inward Dialing (DID): Each user should have DID on the PBX phone system for users who will be enabled for CvW and enabled for enterprise voice in SfB with the corresponding DID.
  
• Automatic Configuration: CvW users must have Automatic configuration selected in their Advanced connections settings. The enables the client to discover the UCWA URLs.
  

  
  

• Call forwarding and Simultaneous ring: CvW users must enable for call forwarding and simultaneous ring.
  
• Dial-in and Dial-out conferencing: CvW users must enable for dial-in and dial-out conferencing which enable these users to get into and out of SfB conferences.
  

  
  

• Delegation, team call, and response group: CvW users should be disabled for delegation, team call and response groups.
  

Deploy Call via Work: Now, let’s have a look into deployment part of the CvW.

• Create a global phone number: for your deployment which Skype for Business displays on the PBX caller ID of users who are making Call Via Work calls.
  

       Set-CsRoutingConfiguration -CallViaWorkCallerId +<PhoneNumber>

• Create one or more Call Via Work policies:
  

        New-CsCallViaWorkPolicy [-Identity] <XdsIdentity> [-Tenant <guid>] [-Enabled <bool>] [-UseAdminCallbackNumber <bool>] [-AdminCallbackNumber <string>] [-InMemory] [-Force] [-WhatIf] [-Confirm] [<CommonParameters>]

• Assign a Call Via Work policy to each user who will be enabled for Call Via Work:
  

        Grant-CsCallViaWorkPolicy -Identity <UserName> -PolicyName Tag:<PolicyName>

Part IV of this article covers limitation in Call via Work.