MS Teams / Skype for Business 2015 / Cisco Call Manager

New Contributor


I just need to verify the below design.

We have S4B 2015 and will integrate it with Cisco call manager and have M365 E3.


Our goal is to migrate some users to MS Teams with enterprise voice to be able to communicate with on-premises users through the assign line URI. 

Based on my understanding there are two ways to do this either using direct routing for MS teams client or using Hybrid voice for S4B Online client.

So, I have some questions to make things clear

Whats the best solution for this scenario?

Do we need to implement SBC in all hybrid scenarios?

Do we need a special M365 license for Phone System (Cloud PBX) to be able to enable enterprise voice for the migrated users?


after checking this article. Microsoft dose not mention if migrating users to MS Teams is double they mentioned only migrating users to S4B online.

2 Replies
I would suggest Direct Routing as the best option in this scenario. If your users have M365 E3 then the phone system add-on will be required (phone system is included in E5 but add-on required for E1/E3). You will also require an MS-Teams certified SBC but the majority of sip trunk providers will offer a 'carrier-hosted' service whereby they host the SBC and provide a subdomain which will need to be added as a domain in your 365 tenant.


Thanks for your reply. I just need to make sure that using Direct routing with Skype for Business 2015 on-primes is doable or its applicable to co-exist direct routing with hybrid voice in my scenario.


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