Mediation Next Hop Settings Expander
You specify the Mediation Server pool or Mediation Server next hop by selecting the defined Enterprise Edition Front End pool or Standard Edition Front End Server from the drop-down list. A Director or Director pool is not a valid selection for a Mediation Server pool or Mediation Server next hop, and will not appear in the list. Click OK to accept and save your changes. Click Cancel to discard your changes and exit the properties page.
For details about the settings for the Mediation Server pool or Mediation Server, see Deploy a Mediation Server in Topology Builder in Skype for Business Server 2015 in the Deployment documentation.