Let me start off by saying I am not a networking expert, nor do I pretend to be one. What I want to focus on in Microsoft Express Route and one of the barriers of entry to Office 365 that it helps to remove. When I talk about a barrier to O365 it comes from experience of talking to clients over several years who were skeptical with connecting to O365 across the unpredictability of the Internet and realize they are pretty much powerless to make much impact on changing the way the internet behaves.
The unpredictability of the Internet should not prevent organizations from utilizing Office 365, after all applications like Exchange on Outlook have features built into them to allow not only for poor Internet connectivity but even loss of connectivity and still allow users to continue to work and in some cases not even be aware they have lost connectivity. But this is not the case for all Office 365 services. Take for example Skype for Business, which needs reliability in connectivity.
Networks that run Skype for Business must be able to support Real Time Media (RTM). Think of the capabilities that Skype for Business provides, like audio conversations, video conferences, content sharing and telephony / dial tone, none of which work well when the network experiences any problems or unpredictability. Microsoft has gone so far as to publish numbers that the network should support for packet loss, latency and jitter so that positive experience can be had for users.
These numbers are guidelines and while Skype for Business will still work if these numbers are not achieved, users will have a negative experience. This is exactly why some companies were reluctant to go to Office 365, especially Skype for Business. How can we guarantee our network connectivity would support these numbers, and support them consistently? Enter Microsoft Express Route.
Express Route allows you to extend your network into the Microsoft Cloud using a dedicated private connection and not use the Internet. Express route allows connectivity into various Microsoft Cloud solutions such as Azure, Office 365 and CRM Online. For our purposes, we are interested in Office 365 since that is where Skype for Business (for the most part) exists. I will not get into the various connectivity options, Layer 2, Layer 3 through multiple carriers, VPN, etc. But know that with Express Route you can now have a faster, less latent and more secure connection into Microsoft Cloud services. If you want more technical detail there is a great article by Cheryl McGuire here.
So, do you need Express Route? In the early days of Express Route the messaging we were hearing was that it was mandatory or highly recommended. Microsoft has changed this message, which I agree with, and recommends that customer perform a network validation (considering Real Time ) as well as evaluate the Office 365 services they will run to determine if Express Route will be of benefit and may I also add how it will be beneficial.