Lync Split-Domain & Static Route Conflicts

Something that is coming up more and more on Lync projects is the concept of integrating with newer video and collaboration services like Acano or Pexip. It's very important to understand that the deployment guides from these services request you create a static route from your Lync Front End pools to their MCUs. This in itself is not a red flag, especially since this is how some of the Polycom DMA or Cisco VCS integration has worked in the past.

However, this does pose a problem for organizations looking to leverage split-domain with Lync Online, or more commonly, Exchange Online being leveraged for voicemail while Lync Enterprise Voice remains on-premises. The issue here is that using your primary SIP domain as the Match URI in the static route to these video services prevents the signaling from getting to your federation Edge servers (at least, as of the latest Lync 2013 CUs.) The static routing configuration seems to kick in before the call is ever routed to the Edge, so the concept of the CsHostingProviders and the shared address space is never respected.

Let's walk through an example:

  • My primary SIP domain in Lync is @confusedamused.com.
  • I migrate my mailboxes to O365 and enable the Exchange Online shared address space. My voicemail is hosted in O365.
  • I want to host large meetings in O365 so I also enable the Lync Online shared address space for hybrid. I have some users homed to O365.

Everything works fine at this point.

  • I now want to integrate with Acano or Pexip. I create a static route for @confusedamused.com which goes from my Lync FEs to their bridges.

This breaks both Exchange Online voicemail routing and communication to Lync Online users.

The real solution here is to use a different SIP domain for your video routing, which as undesirable as this may be to end users, has arguably been a best practice for a long time. Create the static route matching @video.confusedamused.com, @acano.confusedamused.com, or @pexip.confusedamused.com. Take your pick, or create your own variation. It just needs to be different from the SIP domain you actually assign to Lync users.

This is important to grasp if you're using Lync Online or Exchange Online today and looking to add video, but probably even more critical from a roadmap standpoint. Exchange Online Unified Messaging is a fairly common use-case today, and Lync Online hybrid is becoming more and more popular. Planning ahead for these scenarios and any potential video integration will help you avoid these issues.