In my previous blog post, we reviewed how to apply Microsoft’s Office 365 Network Connectivity Principles when virtualizing Office 365 to ensure that workers at branch offices enjoy a great user experience. But I left you hanging on one very important Office 365 application: Microsoft Teams. So let’s explore how to best handle Teams audio-video traffic.

Citrix Optimizes Media Quality and Server Scalability for Virtualized Microsoft Teams

For optimal audio-video quality and Citrix Virtual Apps and Desktops (CVAD) server scalability, the HDX technology stack redirects Teams media traffic to the user device for local processing whenever possible. With the Teams web client, that’s done using an HDX feature called Browser Content Redirection. For the Teams desktop client, Citrix has announced an upcoming Microsoft Teams Optimization (“MTOP”) feature, similar to the HDX RealTime Optimization Pack for Skype for Business Server and Skype for Business Online. This redirects Teams audio, video, and video-based screen sharing (VBSS) to the Citrix Workspace app.

With either optimization, Teams audio-video traffic isn’t going through the CVAD server; it’s processed on the user’s device. The Citrix SD-WAN appliance at the office sees the Teams traffic, identifies and categorizes it, and steers it directly to the cloud, avoiding unnecessary network hops that result in latency.

Minimizing Latency Is Important. Is That Good Enough for Teams?

Latency is not the only issue that can affect real-time Teams audio and video. Jitter (or worse, the huge fluctuations in latency seen on network connections in some parts of the world, which can hardly be described as jitter) has a big impact on call quality. It tends to be even more serious than latency. Packet loss can be even more troublesome.

And what about link failures?

For your organization’s use of Teams, is it acceptable for calls or meetings to occasionally disconnect for some period due to a link issue, or do you want always-on connectivity? Are audio drop-outs, perhaps lasting tens of seconds, acceptable, or do you need a higher level of call quality?

Depending on the level of connection resiliency and call quality your business requires, you can choose from a variety of deployment options.

Deployment Options

Asymmetric Deployment

The most basic implementation of Teams audio-video breakout from your office locations to the Office 365 cloud is a single-ended or “asymmetric” SD-WAN deployment (that is, with the SD-WAN appliance just at the office end of the connection).

With this level of connectivity, audio and audio-video calls will enjoy the fundamental benefit of low-latency connectivity to the Office 365 network thanks to the functionality I’ve explained earlier. And, if one link fails, subsequent Teams calls will use the other link. That may be all you need.

But what if your business demands a much higher level of connection reliability?

Bookended Deployment

A bookended (symmetric) solution offers more advanced SD-WAN capabilities, greatly reducing the impact of jitter and packet loss and maintaining calls without interruption if one of the physical links fails. When a link begins to exhibit excessive jitter or packet loss, Citrix SD-WAN will instantly and seamlessly shift Teams media traffic to the other link. In fact, it retransmits the lost packets so users don’t even notice.

Citrix SD-WAN can even selectively duplicate critical VoIP traffic using a technique called “packet racing.” Each audio packet is sent over two links simultaneously, with the SD-WAN at the other end choosing the first of the two packets to arrive, minimizing jitter. And if a packet is dropped on one link, chances are that it comes through on the other, so packet loss has much less impact. The packets are kept in order by the receiving SD-WAN to preserve audio fidelity.

A bookended deployment also provides end-to-end, bidirectional quality-of-service (QoS). This means that each SD-WAN is aware not only of any congestion on its own network connections but also of the throughput that the receiving SD-WAN is currently able to handle. This approach is far superior to single-ended QoS, which lacks last-mile awareness and cannot act to prevent far-end congestion.

How well does it work?

These advanced technologies have improved customers’ audio quality MOS scores from the 1-3 range to 4-plus. Video quality is higher, too. And if one link goes down, audio and video just keep going, uninterrupted. Such dramatic boosts in quality of experience (QoE) and connection resiliency are possible because, unlike some other SD-WAN products, Citrix SD-WAN is packet-based rather than flow-based, with every packet acting as a probe to provide instantaneous feedback on link quality.

What options are available for a bookended SD-WAN implementation, given that there are no Citrix SD-WAN appliances inside the Microsoft Office 365 POPs?

  1. If latency between the office location and the Citrix Virtual Apps and Desktops servers is low (under 30 ms is ideal), then you can leverage the Citrix SD-WAN there (that is, the one you put in to optimize your HDX traffic and for direct break-out from the virtualized Office 365 apps to the cloud).
  2. If the latency is high, you’ll want a Citrix SD-WAN head-end closer to that office location.

With the second option, you could run your own Citrix SD-WAN head-end on Azure or another supported public cloud platform, as shown below.

Alternatively, for offices in the United States and Europe (and soon this will expand to many other countries), you could connect to Citrix’s Cloud Direct service, currently in tech preview and soon to be generally available. This service applies SD-WAN techniques such as path quality monitoring, link aggregation, intelligent load balancing and path failover to Internet links, connecting your offices to a managed, high speed, highly redundant Internet overlay network that’s directly peered to thousands of cloud and SaaS providers at major internet exchanges. It even provides “same IP failover” so calls and other connections continue uninterrupted even if catastrophic failures cause a POP to go down, allowing traffic to be moved from circuit to circuit or POP to POP transparently to the endpoints. With bidirectional QoS, Citrix Cloud Direct continuously protects voice, video, and other critical traffic streams.

Optimal Performance on All Three Critical Network Connections

If you follow the recommendations that I’ve outlined here and in my first post, your network will be tuned for virtualized Office 365 traffic. Citrix SD-WAN will deliver a satisfying Office 365 experience to your workers by optimizing the traffic flows between:

  • Office locations and CVAD servers
  • Office locations and the Office 365 cloud
  • CVAD servers and the Office 365 cloud

Need Help?

Are you keen to bring these benefits to your organization, but not quite sure how to proceed? Citrix has a network of knowledgeable partners ready to assist you. Go to our Get Started page and select “Contact a partner” to find a certified Citrix Solution Advisor near you.