In an edge friendly branch survivability configuration, the branch network is distinct from the enterprise network (core) and the connectivity between them is over the Internet rather than the VPN.

An Avaya Session Border Controller (SBC) is required at the core edge for connectivity to the branch. Third-party SBC is not supported in an edge friendly branch survivability configuration.

For management functions, an Application Delivery Controller (ADC) or a reverse proxy is required in the core to support the tunnel between the branch and the System Manager. A tunnel is an outbound connection from the branch to the core and does not contain any inbound connection. The tunnel supports bidirectional traffic between System Manager and Branch Session Manager (BSM) for all management functions, including database replication.

In an edge friendly branch survivability configuration:

• The SIP connections between the BSM and SBC use a connection reuse strategy as per RFC 5923 to support the traffic in both directions.

• All endpoints in the branch connect to the core as office workers by using the SBC. This applies to both SIP and PPM connections to the core.

• Management connectivity from the BSM to System Manager that is located in the core is made over the tunnel.

• A similar tunnel exists between the Survivable Remote Server (SRS) and main Communication Manager to support communication between the SRS and Communication Manager. For example, to support updating of translations on the SRS from the core Communication Manager.

The following diagram depicts an edge friendly branch survivability configuration:

The following diagram depicts tunnel connections for the management functions between Branch Session Manager and System Manager and SRS and main Communication Manager through an ADC or reverse proxy:

Legend

• BSM: Branch Session Manager (Survivable Remote Session Manager)

• CM: Main Communication Manager (Feature Server and Evolution Server)

• SRS: Survivable Remote Server, formerly known as Local Survivable Processor (LSP)

• SCS: Survivable Core Server, formerly known as Enterprise Survivable Processor

• MG: Media Gateway

• SM: Session Manager

• SBC: Avaya Session Border Controller

• SMGR: System Manager

• ADC: Application Delivery Controller