Lync’s new Survivable Branch Appliance is a hot topic and while I am not going to cover the entire solution in one post I just wanted to touch on one area. What happens to the client experience when the WAN goes down? By far the most common question I get around SBA functionality.
Firstly, the most obvious is the big red banner across the client. Although these screen shots are from the beta, the behavior and look for this feature is still the same with RTM. The end user has a clear indicator that there is something going on. Secondly contacts and presence have disappeared. The example screen shot shows that once in failover mode even though contacts are gone you can still search the address book. In this case if Marcos is registered with the same SBA device, Mark can still do peer to peer IM/Presence, audio, video etc. though the Lync client. If Marcos is registered elsewhere Mark can still make outbound calls from Lync through the default PSTN gateway that is configured on the SBA. So voice is still available for PSTN calls.
Above is a great breakdown of what is and is not available during a WAN outage. The most critical feature that is maintained is voice. The user can also still reach and host conference calls through the PSTN although the interface to control the conference will be through the DTMF interface.