Assume that you deploy multiple front-end pools or the federation feature in a Microsoft Lync Server 2013 environment. A user who has more than 100 contacts in a different front-end pool or in the federated environment signs in to Lync 2013. In this situation, a "Presence unknown" status for many of the contacts is displayed in Lync 2013 within 30 minutes.
Note If the user starts an instant message conversation with one of the contacts, the presence status of the contact will be updated immediately.
Note If the user starts an instant message conversation with one of the contacts, the presence status of the contact will be updated immediately.