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Considering ExpressRoute to improve Office 365 performance


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Considering ExpressRoute to improve Office 365 performance

We’ve heard contradicting rumors about ExpressRoute. For example, it has been said that ExpressRoute makes mailbox move significantly faster or that ExpressRoute makes Exchange Online slower because it was designed to improve security. 

The last rumor people tend to believe pretty heavily is that ExpressRoute will significantly improve Office 365 performance. So, what really is ExpressRoute? 

The shortest way to explain ExpressRoute is that it is a logical connection between a peering provider (that provides you with ExpressRoute) and Microsoft peering location. 

The first thing to really understand is that ExpressRoute is not designed to be a performance solution and it is not designed to be a security solution either. 


How we test it? 

There are 3 different ExpressRoute technologies. The one we studied is the one that connects to Office 365. It is called Microsoft peering. 

We tested the access to Exchange Online with or without using ExpressRoute. For that, as usual, we tested the access to the mailbox and a few other actions. 

Schema of our tests 

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Results on Exchange Online performance  

There is no need to show reports here.  As expected, results did not provide any evidence of performance benefits for the end-users. 

Depending on the time of the day and the action, sometimes using ExpressRoute provided the Robot better performance and sometimes it did not. This means that it had no real consistent impact on the end-user experience for any of the actions that we tested (open mailbox, create meeting, create task, resolve a user, free/busy lookup, download attachment). 

And again, these were the results that we expected. 

When you look at what ExpressRoute is, it is a connection to a designated Microsoft peering point. There are many other parameters that will impact the performance of ExpressRoute; such as the peering point location. 

However, there is no guarantee that your entry point with ExpressRoute is better than the one you already have with your Internet Provider entry point. There is no guarantee that is worse either. 

ExpressRoute will give more predictable performance which means predictably worse or better, but it is not designed to improve performance. 


A different case with Skype for Business Online


Considering ExpressRoute to improve Skype for Business Online voice & video quality seems to make more sense.  

As you can read in our RoboTech articles addressing Skype for Business Online, you can implement the QoS in your company’s infrastructure but you cannot force your ISP to do so.  

The QoS is a way to always have a part of your bandwidth assigned to audio & video calls data. It means that no matter what other Internet traffics 
you have, the media data will always have a designated bandwidth on your network. The problem is that your ISP is not working the same way.  

The only way you can have a full QoS path between your users and the Microsoft Edge entry point is to implement Azure ExpressRoute.  

Azure ExpressRoute has the QoS implemented, marking every packets and prioritizing them to increase video and audio quality for the end-users. 

Azure ExpressRoute is not a solution that is designed to improve overall performance of your connection to Office 365 services. It means that it won’t necessarily improve your SharePoint or Exchange Online end-user experience.

But because it has the QoS implemented natively, it should improve the Skype for Business packet delivery, decrease your packet loss and improve your overall MOS on audio and video quality.

On top of that, the big advantage of the Azure ExpressRoute is to deliver predictable performance.

You will have always the speed and bandwidth for your Office 365 services needed during busy or non-busy hours, no matter how your Internet connection is used.

Finally the Azure ExpressRoute will provide you with a SLA of 99.9% of network availability between your egress point and the Microsoft edge entry point.


Conclusion on ExpressRoute and network performance

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The first thing you need to evaluate if you’re going to use ExpressRoute to improve distance performance. That is, how you’re going to get to the Microsoft network in the shortest amount of time.

You need to understand what city you’re in, what is the ExpressRoute entry point in your region, and where your ISP can get you into the Microsoft network. Without these details, it is impossible to properly build the latency calculation that you need to understand your connection.

This diagram below is a good way to understand the ExpressRoute. You can have a nice, clean, easy path but it can be significantly longer than the original one.

If you want to improve end-user performance and you have money to spend, between bigger bandwidth and ExpressRoute, you should first take a look at how to improve your bandwidth.


Increasing the bandwidth locally is a much better decision. You will end up with a much faster direct connection instead of taking the longer path with ExpressRoute.

But again, things might be different if you are considering ExpressRoute to improve Skype for Business Online.

In order to improve your Skype for Business Online performance, we highly recommend reading the set of articles published on our RoboTech Library.

Regarding Exchange Online, if you know your message flow rate, and you understand your use case, you can run a Microsoft tool to calculate your needed bandwidth. It will help you calculate for peaks and value of the busy times of your data.

You can take that data and compare it with what you have available on your current internet connection.

The calculation of how much you need for Office 365 is the easier part, as Microsoft provides it for you. Also, it is important to understand the components of your network and the speed in which it operates.

Where is your connection point? Can your ISP get you in the Microsoft network faster? There are plenty of factors that will impact the end-user experience. And again, if you don’t measure it, you can’t work on improving it.