In the event of a WAN outage, users in branch sites will have continued voice services through the use of a Survivable Branch Server or Appliance because the primary registrar service is local to the site. The clients will enter “Limited Functionality Mode,” in which not all features are available to users while the WAN link is unavailable. Figure 32.5 shows how a branch office user remains connected to the local registrar service when a WAN link is unavailable.
During a WAN outage when branch users cannot contact a Front End pool, the following features are unavailable for users inside the branch:
• Cross-Site Communication—Any form of communication to other sites is unavailable.
• Conferencing—All conferencing is unavailable. ...