The Web Application Server is not a true Skype for Business Server 2015 (SFBS 2015) role, but a SharePoint role that SFBS 2015 leverages for its document rendering of Office related applications.  The Microsoft Skype team went with a more formidable approach to document rendering in turn is accomplishing several things at the same time with regards to standardizing the way various products present Office based documents to non-standard devices such as tablets, IPhones, MACs, and other mobile devices as well.

The Web Application Server will be solely responsible for allowing SFB clients to present PowerPoint presentations to audiences regardless to the device the recipient is using. With the standardization of SFBS 2015 using SharePoint for its document rendering process comes with benefits that previous version of Skype didn’t provide such as higher-resolution for video and PowerPoint capabilities such as attendees having the ability to move ahead through PowerPoint slides independent of the speaker. 

We are going to take a look beneath the surface at some key areas that make-up the Web Application Server:

  • Web App Server Architecture 
  • Web App Server Inner Workings 
  • Web App Server Deployment Best Practices

Web App Server Architecture

Being that the Web Application Server is not a SFBS 2015 server role, we are not quite adding an additional Skype server to the topology but we are adding a shared component to the topology.  The Web Application Server will exist within the network and become and additional server outside of the Skype roles that is called upon for services such as Exchange and SQL.  The Web Application Server (WAC) will be responsible for providing service to the organization, so in the event that a single node is not available services for document rendering still need to take place which in lies resiliency. Microsoft recommends to set up a centralized Web App Server farm so all related components can leverage its usages

Note: The Web Application Server requires a dedicated server and shouldn’t be collocated with any other Skype server role.  The Web Application Server can reside on physical hardware or virtual machine.  

In a SFBS 2015 Enterprise Edition deployment (5,000 or more users), the Skype2015 Pool is set up as usual.  When identifying the Web App server, this is done in the topology builder by specifying a URL of the single Web Application Server or load balanced Web Application Server farm. 

SFBS 2015 Standard Edition is usually used for small deployments (5,000 or less users) and in these scenarios you would have a Skype Standard Edition and a Web App server. You would not collocate the Web Application Server along with the Skype2015 Standard Edition server.  As the SFBS 2015 Enterprise Edition deployment you would need to define the URL for the Web App server when deploying Skype Standard Edition in the topology builder.

Figure 1: Office Web Apps Server FQDN url configuration in Skype 2015 Topology Builder

Web App Server Inner Workings

To improve the Skype user experience of users who wish to present or view PowerPoint presentations, SFBS 2015 uses Office Web Apps Server to handle PowerPoint presentations. The following walkthrough details the process that occurs when a user uploads content and when viewers download the presentation.

Figure 2: Web App Server Document Flow

  1. Sharer uploads a PowerPoint file into the meeting to the Web Conferencing Server 
  2. The Web Conferencing Server encrypts the file and sends the file to the Skype Content File Share without any conversion.   
  3. Web Conferencing Server creates a dynamic URL (This URL is in the config database and is when you deploy the Skype server, you identify where the WAC server is located) that will send to presenter and audience. Note: URL contains the file ID also the base URL for the conference which allows the viewer to point to the WAC Server 
  4. When the request is made to present a file, the base URL is taken encode a few things (such as file ID, meeting ID, unique identifier of the actual FE server hosting the meeting) and send it to the client. Note: Additional security is also provided by session lifetime token and is put in the URL.
  5. Viewer client clicks on the URL to view the presentation to request from the WAC server. 
  6. WAC server makes a request to the Web Conferencing server asking for the presentation (on a first time request)
  7. Skype Content File Share server provides the presentation to the WAC Server
  8. Viewer is able to see the content
  9. User is able to download content from WAC server directly 

WAC Deployment Best Practices

The following are some deployment best practices from the field:

  • Make sure you have a dedicated machine that doesn’t have any Skype 2015 server roles located on it before you begin deployment.
  • Confirm that you download the Web Application Server updates along with the actually installation bits. Update for Microsoft Office Web Apps Server 2015
  • When creating the certificate for the Web Application Server be sure the “Common Name” is actually the FQDN of your single server or the FQDN of the Web Application Server farm.
  • Once you configured your certificate be sure to confirm validation of certificate and configuration by running the typing the https://FQDN/hosting/discovery into the browser from the Web Application Server and verifying XML output.

Web App Server Final Thoughts

Despite an additional server involved in the SFBS 2015 deployment process, Microsoft has taken a giant step forward with moving toward a standard document rendering process across applications.  The ability for Office documents to leverage the SharePoint 2010 and 2015 process for Skype conferencing and presentations for rendering brings together a tighter integration between Skype and SharePoint.