As businesses examine their options for migrating to Unified Communications with Microsoft Lync, many are looking at cloud-based solution for reduce capital expenditures and shift to a pay-as-you-go subscription model. With Lync 2013, there are numbers of options such as hosted cloud, dedicated cloud and hybrid cloud.
However, moving to the cloud does put a significantly greater dependency on the WAN, and without a survivability strategy, a simple firewall miss-configuration or network interruption can put even basic voice communications out of service.
Survivable Branch Appliance (SBA)
For mid-sized cloud customers or branch sites with between 25 and 1000 seats, Microsoft recommends use of a Survivable Branch Appliance (SBA), a hybrid server/gateway network element that includes a server to host local copies of Lync Server Registrar and Mediation Server along with a local media gateway for access to PSTN circuits. SBAs allow mid-size cloud customers to continue business operations in situations when the wide-area network or Lync server pool in the cloud were to be unavailable.
- Branch office resiliency for up medium to large branch offices with up to 1,000 users
- Maintains Lync voice services during WAN or central Lync server outages
- Integrated, highly scalable media gateway and session border controller
- Ability to host additional value-added enterprise applications
Resilient Branch Appliance (RBA)
There is a new Lync Survivable Branch option called the “Resilient Branch Appliance” or RBA. The RBA brings branch survivability via 3G/4G wireless mobile broadband to keep the signalling and data layers operational during WAN outage.
RBA essentially takes the Survivable Branch Appliance and extends its capabilities with WAN resiliency with either redundant wire line WAN connectivity or wireless 4G to facilitate alternate routes for data connectivity, control and messaging while using local PSTN connectivity to carry voice during a WAN outages. Designed for small offices, RBAs are ideal for retail, financial services, insurance and other businesses that have many small branch offices and a requirement for business continuity during extended network interruptions.
It appears that 3G/4G keeps signalling, presence, address book and web conferencing going during an outage of WAN. Voice is handled via PSTN breakout.
- Cost-effective Lync survivability for small branch offices
- Uses redundant WAN links to ensure uninterrupted connectivity with the central Lync servers
- Fully compliant with Microsoft SBAv2 specification
- Integrated router, firewall, VPN, media gateway and session border controller
- Can be used in conjunction with SBA to add IM and presence in resiliency mode