Skype for Business Video Interop Server – Part 1


This is part 1 of a two parts article where I will be talking about planning, installing and configuring the new server role Microsoft introduced with the release of Skype for Business Server 2015, the Video Interoperability Server.

Many companies have their existing Cisco video teleconferencing systems and when thinking of integrating this with existing or ” a To-be” Skype for Business infrastructure they find out that the cost will be high because when it comes to video integration between Microsoft and Cisco it is never a direct integration and is possible, or let’s say was possible only by using a 3rd-party solutions which will increase the investment even more.

Well if you have a Cisco Video Teleconferencing system and want or considering deploying Skype for Business but worried about your investments, worry no more, Skype for Business Video Interoperability Server “VIS” is designed for your situation and with no additional cost.

What is VIS

Video Interop Server, is a new role shipped with Skype for Business server 2015 that allow video conferencing between 3rd-party Video Teleconferencing system as in Cisco/Tandberg systems and Skype for Business server.

What can it Do

Here is a list of what VIS is designed to do :

  • Conversion between H.264 formats used by Cisco systems and Skype For Business.
  • FEC “Forward Error Correction” can be enabled to help reduce package loss (it will increase the video bandwidth by 50% direction to VTC)
  • Adopting & converting the coming video stream from the Cisco VTC (Single stream, specific resolution) into multiple streams of different resolutions for use in Skype For Business.
  • VIS currently can be deployed ONLY as a Standalone server, it cannot be collocated with other Skype For Business roles.
  • VIS been tested and found working good with CUCM 10.5 and above.
  • VIS been tested by “TAP Customers” with Cisco Telepresence Video Communication Server (VCS) 8.1 and found working fine, nevertheless this was not tested by Microsoft nor it is officially supported yet.
  • Cisco devices will need to have software release TC7.0.0 or above to work as expected with Skype For Business.
  • The Integration between both platforms are done by using SIP-Trunk.
  • VIS to multiple CUCM trunks (1:N) is supported.
  • TCP/RTP is tested and working as expected, some problems occur with TLS but it is still supported
  • The VIS deployed as a part of Skype of business topology can be used with Lync 2013 server in a co-existence scenario (Lync 2013 must have the correct CU)


Some limitation still exist in the integration and I don’t see them as a deal breaker, but you need to keep them in mind:

  • Call can only be initiated from the Cisco VTC to Skype for Business, also drag and drop not possible yet.
  • Presence & Application Sharing is not Supported
  • Only VIS Standalone pool is supported
  • TLS/SRTP have some issues
  • VTC cannot join a federated Skype For Business conference
  • VTC cannot join an online meeting
  • Call from VTC to VIS via PSTN not supported
  • Call from PSTN to VTC via VIS not supported
  • VIS does not support transcoding between RTVideo and H.264
  • VIS cannot be used in a Hybrid deployment with Skype for business online.

How is it done

So as I mentioned previously, the integration between both platforms are done by using SIP-Trunk, the trunk will be defined on the Skype for Business topology as well as on the CUCM side, the VTC will continue registering to the CUCM, no changes here.

High Availability

You might want to consider high availability for your video conference infrastructure, this can be done by two options

VIS pools failover

Two VIS pool with failover, so that if the primary VIS pool is down, the video gateway “Cisco CUCM” can still route the video call to the backup VIS pool, because the Topology won’t allow you to do have same Video gateway “Cisco CUCM” pointing to two different VIS pools, the trick will be as following:

  • In DNS, add two different A-records pointing to the same IP-address of the Video Gateway “Cisco CUCM”

  • In the topology add those two FQDN of the Video Gateways.
  • Assign each video gateway to a VIS pool

By this you have tricked Skype for Business to have the same Video gateway pointing to different VIS pools for failover.

Frontend pool Failover

When a video call comes to the VIS from the video gateway, the VIS then forward it to the AVMCU (Frontend Pool), then the Frontend pool forward the call to the correct Skype For Business client.

The VIS keep track of the availability of the Primary Frontend pool configured as the “Next Hop” in the topology.

This is done by sending “OPTIONS” messages to the pool, if 5 consecutive failures messages are received, the VIS will mark the frontend pool as “Down”, If there is an online backup Frontend pool configured for the VIS, the VIS will start routing the calls to the backup frontend pool, meanwhile the VIS will keep trying with the primary frontend, and once it finds it online again, all new calls will be forwarded to the primary frontend pool, There is also always the option for the admin to invoke a failover using the Skype for Business management Shell commands.

Same Voice & Video Gateway

Most organization would have the CUCM serving as PSTN & Video gateways, well good news is that it is supported to have the same CUCM serving as a PSTN gateway and video gateway in the same Skype for Business topology, following screenshot you see I have one gateway “CUCM01.lyncdude.local” used as a video gateway and voice gateway for Pool01.

In Part-2 I will be writing about defining a VIS in the Skype for business topology, installing the VIS and configuring it.

Author: Lyncdude

A Senior Service Engineer with more than 9 years of experience in Microsoft Exchange and Microsoft Lync Server / Skype for Business. Egyptian guy lives and works in Frankfurt - Germany. what is written in this blog is my own opinion and thoughts, not my employer and does not reflect their opinion

6 thoughts on “Skype for Business Video Interop Server – Part 1”

  1. Nice article. Two questions:-

    1) Very few CUCM deployments are running 10.5. Having to have such a new version seems a blocker to adoption.

    2) Why would you run VIS and VCS in parallel other than for migration, short term coexistence?

    1. Thanks Shawn,
      1- here in Germany most of the companies i worked with have 10.5, and in the end it is a decision for the management if they wanna save their investment then they should upgrade 🙂 also i think it will work with older version 9.1 but won’t be supported by MS, that’s the trick
      2- yes Co-existence is a reasone

  2. Great article.
    2 things

    1.) Your comment about the OPTIONS statement is a little confusing, instead of saying failure messages received, the line could perhaps say if 5 OPTIONS probes fail? as if the server is down no response is sent to the OPTIONS request

    2.) There is still a cost involved in deploying a VIS server, as it is a Lync sever role and cannot be co-located the VIS role would need a Windows Licence, and a Lync Standard Edition licence

    Anyway, great to see information on the new platform out and about.

  3. “VIS been tested by “TAP Customers” with Cisco Telepresence Video Communication Server (VCS) 8.1 and found working fine, nevertheless this was not tested by Microsoft nor it is officially supported yet.”

    Is there a way to access documents describing VIS-VCS interoperability made by these customers?

    Nice article!

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