An SBC (Session Border Controller) allows the data center to have its own addressing scheme, independent of the addressing schemes of the branch offices.
The choice of using a central SBC in the data center or SBCs in each branch office depends on several factors:
Need for media relay function via an SBC in the data center. The Enterprise policies may require RTP (Real-time Transport Protocol) media to pass through the data center rather than allowing direct media connections between the branches.
Need for media transcoding at a central media relay SBC, e.g., between SRTP (Secure Real-time Transport Protocol) and RTP or between different payload types (codecs).
Need for enhanced security/firewall capabilities of a central SBC.
Need for fast recovery from Lotus Sametime Unified Telephony node failover, particularly in a geographically separated data center configuration. All other effects being equal, the branch SBC can provide faster recovery times; although if the branches are connected to the data center via the public internet and VPN's are used then the advantage of the branch SBC is lost.
If a branch office includes a PSTN (Public Switched Telephone Network) gateway, there are two possibilities:
the gateway is only used for PSTN access when the branch is in survivability mode;
the gateway is used for PSTN access during normal mode (as well as in survivability mode).
The configuration of a central SBC must take account of the second possibility and provide the capability to route SIP signaling between the branch gateway and Lotus Sametime Unified Telephony via the SBC.
Parent topic: SBC (Session Border Controller)