The success of MS Teams has generated the use of new terminology that was not common in corporate voice networks. Media Bypass is a mechanism provided by Microsoft to optimize the path of media traffic (improves performance by avoiding any of the hops). With Media Bypass, this media traffic is established directly between the Session Border Controller (SBC) and the telephony client, instead of sending them through the Microsoft cloud, which can generate additional latencies and points of failure. To configure Media Bypass, both the SBC and the telephony client must have layer 3 visibility (within the same network).

When we do not have “Media Bypass” active, when a telephony client makes or receives a call, both the signaling traffic and the media flow pass between the SBC, the Microsoft telephony system and the MS Teams client, which logically It does not seem like the best solution in case both the MS Teams user and the SBC are on the same network or location. This is shown in the following image:

This implies that a call between an MS Teams user and another that depends on the pre-existing PBX will pass its voice traffic through the MS Teams cloud, which sometimes does not have infrastructure in the same country, despite that both users can be on the same network and location. While Microsoft denies that this has no noticeable impact on call quality (due to supposed optimization of traffic flow within Microsoft networks in most scenarios) they have enabled the Media Bypass mechanism to prevent this.

With Media Bypass, media traffic is established directly between the MS Teams user and the SBC , as shown in the following diagram:

Media Bypass makes use of protocols called“Interactive Connectivity Establishment”(ICE) in the MS Teams client and in the SBC. This is why it is necessary to use SBCs that are approved by Microsoft. These protocols allow Direct Routing to use the most direct route for average traffic, with the goal of achieving optimal quality.

Quobis currently gives interconnection services with MS Teams to dozens of clients, with different architectures and use cases, which allow us to give an independent perspective.

Access to the MS Teams cloud is done by most clients through the Internet, without using networks that are dedicated or that offer a certain quality of service . The Microsoft cloud, still optimized in terms of routing and with the possibility of using low rate codecs (SILK), represents a loss of efficiency if all average traffic is routed through that network.

The possibility of connecting media traffic directly to the SBC , whether on-prem or offered as a service by a telephone operator, is an interesting alternative to avoid bottlenecks and quality problems in communications.

This is why we recommend using Microsoft certified SBC as a Service the best ally in interconnection projects with MS Teams, as well as having a specialized partner. SBC manufacturers may include additional licenses to support codecs preferred by MS Teams or to terminate media traffic, so it is important to decide which option best suits the customer.