The back to back H248 a proxy establishes proxy connection between one or multiple branches over a public network, while the datacenter is located in different networks. To support this mechanism, the SBC is set to function in two modes:
Branch-Edge Mode
Core Mode
By default, SBC is set to the Core mode. These modes can be changed after installation.
SBC in branch-edge mode
In this mode, the gateway connects to the core mode SBC over a public network and set up a connection with datacenter.
Note:
To ensure the media anchors on the branch-edge SBC, you must select the Media Anchoring check-box, while configuring H248 relay.
The back to back H248 proxy un-anchors the media between the two branch-edge SBCs, while the media connectivity is not certain. When media is not anchored on the core SBC, it is either placed on the local branch SBC or connected to remote branch SBC. The branch SBC maintains a connection per gateway with the core SBC and each connection on TLS.
SBC at core
In this mode, the media is transferred within a NAT region. The usage of branch SBC is not mandatory and can be eliminated. In this design, the core SBC communicates with the gateway directly. If core SBC fails, the branch SBC also drops the connections towards the gateway.
