Jan 28

Microsoft Teams and the protocols it uses, OPUS and MNP24

I was wondering which protocols it was using. I heard some rumors the architecture was build around Skype consumer. I found a very good blog around this describing it. In February 2005 I wrote a blog if the new OPUS codec (based on SILK) was to be used in Skype for Business. It wasn’t, but it is now Microsoft Teams!

You can find it here:

Microsoft Teams – SIP IS NOT DEAD! It’s Just Somewhere Else!

Some great excerpts from the blog:

“This new core as I said before is built on Skype consumer code. This does not mean that it uses the Skype consumer datacenters, network or PSTN services. That is separate! It is just the code framework they have copied over to develop an enterprise grade audio, video and meeting service, that is exposed to the end user through Microsoft Teams. This is the reason why you will still see the Skype logo in your audio, video and meeting experience. This can be best explained in this simplified diagram.”

“So when we talk about Microsoft Teams does not use SIP, then at a technical level you are right on two points. The first point is that Microsoft Teams itself doesn’t require SIP, it is an end user UX App window that exposes different Apps such as Chat, Calling, Meetings etc. The second point is that the new Skype core service is based on Skype consumer code and therefore does not use SIP as it’s signaling protocol. Instead it uses Microsoft’s own signaling protocol called Microsoft Network Protocol version 24 or MNP24 for short. This protocol is wrapped inside a TLS encrypted TCP packet, which means, unless you have the private key for the Skype servers in Office 365, you ain’t gonna see it. However, what you need to understand is that this protocol is used between the Skype core and the App exposed with the Microsoft Teams client on your desktop. It does not replace SIP within the Microsoft Phone System. Another point to make is that the media codecs between the Skype app in the Teams client and the Skype core will be H.264 for video, SILK for P2P and Voice calls, and OPUS for meetings. But this will be only between the Skype core and the client the end user is using. At a higher level, the Skype core needs to interop with SIP, specifically the Microsoft Phone System and Audio Conferencing. “

“The following compacted diagram shows what was have explained at high level”

“In summary, SIP is not dead and you should not be concerned with this drift away from SIP as far as the desktop / web client is concerned. MNP24 has been in Skype consumer since 2014 and is a robust protocol. It allows Microsoft to develop their own components without the limitation of standards based protocols, which is good for development, but also carries risk around compatibility.”

People some times get confused on what Microsoft application to use for what. Described here by Microsoft is what to use when:


Microsoft Teams
Leveraged by means of customers and groups who are trying to collaborate in actual-time with the same institution of people.
Facilitates teams seeking to iterate quickly on a undertaking even as sharing documents and taking part on shared deliverables.
Permits users seeking to connect a huge range of gear into their workspace (such as planner, strength bi, github, and so on.)
Leveraged through customers who prefer to collaborate in the acquainted surroundings of e mail and/or a more formal, dependent manner.
Offers particular business methods that require e mail usage to transmit documents and records inside and outside company obstacles.
Communicates and connects with users who are outdoor of instantaneous workgroups or corporations.
Leveraged to assist join customers across the business enterprise to arrange around communities of practice and percentage great practices.
Improves move-practical workflows via an open and obvious feed-based totally platform
Fosters government-employee engagement with two-manner conversations between leadership and the broader worker base
Ignites your frontline personnel to share and obtain expertise and information
Skype for Business (Teams replacing it)
Leveraged for actual-time verbal exchange and collaboration both internally and externally with customers/companions.
Provides conferences with audio, video and content material with small or huge teams (along with city halls with up to 10,000 contributors).
Gives enterprise telephony functionality.
Leveraged for sites and portals (e.G. Agency information & bulletins, search, and file collaboration).
Implements business system automation on file libraries and lists of records by using integrating microsoft glide and powerapps.
Complete-powered sharepoint team site mechanically provisioned for each microsoft crew for record storage, crew news, pages, lists and more.”


Leave a Reply

Your email address will not be published.