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Microsoft Teams Direct Routing Staged Migration from CallTower Skype

Microsoft Teams Direct Routing Staged Migration from CallTower Skype

This document will provide basic recommendations and information regarding a Direct Routing with Microsoft Teams staged migration. This document is intended for customers currently utilizing CallTower Skype for Business. New customers should contact their Sales representative or their Implementation Project Manager.

Recommended Methods for Pre-testing before deciding on Staged Migration Path:

IT staff and other power users should test Microsoft Teams calling functionality by using Microsoft Teams Calling Plans instead of Direct Routing. Along Side of using Audio Conferencing Licenses to test the Conferencing functionality.

This can be accomplished with little effort and is something that can be done today by current IT staff. Current Microsoft Vendor or CSP should be able to assist with getting the correct licensing in place and setup.  

Once there is a firm understanding of the functionality.  Moving forward with a Staged migration to Direct Routing is possible keeping the below points in mind to understand the limitations of a staged migration from CallTower Skype to Microsoft Teams Direct Routing.    

  • We do still recommend a full cut-over at once migration if possible. 

Staged Migration Information: 

  • Migration requires using a separate SIP domain for Skype for Business Online.  
    • This requires the implementation of Microsoft Teams to be complete on the Office 365 tenant. 
      • customer.pstn.ctteams.services created for use as a separate Skype for Business Online domain. 
      • customer.onmicrosoft.com domain can be used as well.
  • Azure AD Sync is required to manipulate SIP Domain for all users.
    • Documentation for this can be provided.
    • Assistance in this process will require Professional Services.
      • Requires an alternative sip domain for Microsoft Teams/Skype for Business Online be implemented.
  • Migration of DIDs from CallTower Skype for Business to Microsoft Teams Direct Routing.
    • Requires AD Sync (Separate SIP Domain).
    • Requires Teams Implementation be completed.
    • Requires Connect Service Account created on Tenant.
  • Co-Existence Mode should be set to Islands, until all users/numbers are in Microsoft Teams Direct Routing.
    • This determines how Skype for Business/Microsoft Teams devices interact with the tenant, and how calls are handled between the two platforms.
      • Users which require Call Queues must be set to Teams Only mode as needed.
        • Call Queues do not support Skype for Business Devices and require Microsoft Teams Devices or Microsoft Teams Client Only.
      • Skype for Business Certified Hardware Phones will work with Skype for Business SIP Domain during migration.
        • Poly VVX Series
        • Yealink T4xS Series
      • Skype for Business Certified Hardware Phones will NOT work with Microsoft Teams during migration.
        • Recommend Microsoft Teams Certified Phones.
        • Once migration is complete Skype for Business Phones will work with Microsoft Teams.
  • Skype for Business interop in Microsoft Teams is not supported until migration is completed.
    • This means SIP Domain is moved to Skype for Business Online. i.e. Teams Only Mode
    • This includes Federation, IM, Voice, Video, Etc.
    • Dial by Number will work cross platform.
  • Federation in Microsoft Teams is not supported until migration is completed.
    • This means SIP Domain is moved to Skype for Business Online. i.e. Teams Only Mode.
    • Federation would still function in Skype for Business Client running side-by-side.
  • Transfer Calls by name (Directory) is not supported Cross Platform.
    • Recommend using DID to Transfer Calls instead.
    • This could be partially mitigated with extension dialing; However, CallTower Skype for Business users will not have extension dialing available to them.
    • This is for transferring calls received on one platform that need to be transferred to another.
      • Skype for Business to Microsoft Teams transfer
      • Microsoft Teams to Skype for Business transfer
  • CallTower Connect Integration requires Skype for Business Admin Service Account to be provided or CSP relationship established.
  • There is no way to create a hybrid link from CallTower Skype for Business to an Office 365 Tenant.
  • Microsoft Teams / Skype for Business Online can not be configured with the correct SIP Domain until all users have been migrated.
  • It is possible there would be other unknown limitations which we have not encountered in previous staged migrations.