One of the big advantages of deploying Lync in a distributed office environment with one or more branches is that Unified Communications (UC) brings employees in geographically dispersed locations closer together, through presence, IM, desktop sharing, voice and other UC functions.

One approach centralizes the Lync servers at a corporate data center.  All UC communications are routed through the Lync infrastructure located at the main office, including calls between extensions within a branch office, and calls to the Public Switched Telephone Network (PSTN).

However, if the connection between the branch office and data center is lost, Lync functionality becomes unavailable at the branch office.

One way to mitigate functionality loss due to a dropped WAN connection is to implement a Survivable Branch Appliance (SBA) at each branch office.  Supplied by Microsoft partners, an SBA includes essential hardware and software components to ensure that key UC functions are  sustained in the event of WAN failure.

An SBA maintains the ability to route calls between Lync clients within the branch office, and to external phone numbers via SIP trunks or the PSTN.  However, other UC functions at the branch are lost when the WAN drops, including presence, conferencing, screen sharing, whiteboard, and file transfer.  This is not acceptable in environments where Lync has been fully integrated into mission-critical corporate workflows.

Lync Express Adds Continuous Survival

Sangoma takes the idea of the survivable branch appliance one step further – the preservation of all Lync UC services at the branch office.

If the corporate WAN connection is lost, the Lync Express appliance maintains full functionality of all Lync UC features (as described above) within the branch.  Lync Express can maintain telephony connectivity via locally connected SIP trunks or PSTN connections.

Locally connected SIP trunks are effective when the branch office still has an outside data connection.  Under normal operating conditions, they also reduce the load on the main office internet connection and Lync infrastructure.

Local PSTN connections ensure outside telephone access is available even when SIP trunking service is interrupted, by a lost internet connection for example.  A variety of PSTN interface boards are available including analog, BRI and T1/E1.

Lync Express packages all of the key software and hardware elements required to handle a continuous survivable branch installation in a single appliance, hosted on a “right-sized” server.

Microsoft Lync Express

NetBorder Lync Express

Enable Microsoft Lync for an SME of up to 100 employees.
ISDN PRI connectivity to the PSTN assured by Lync certified NetBorder Express VoIP Gateway.
Connect legacy telephony devices (fax and phones) to Lync UC services.
Integrate with Office 365 services with Lync on-premise.