In an FA solution, the FA Server performs the role of connecting FA Clients and FA Proxies to the SPB fabric, with minimal configuration. As part of the discovery handshake between the FA Server and client or proxy devices, LLDP PDUs are exchanged. Using standard LLDP, the FA Server learns neighbors, that include the proxy and client devices. In addition, the FA Server transmits organizational-specific element-discovery TLVs that are used by the client or proxy device to recognize its attachment to the FA Server.
After the initial discovery handshake is complete, the client or proxy device transmits I-SID-to-VLAN assignment mapping requests to the FA Server to join the SPB fabric. These requests include the C-VID (VLAN ID) and the I-SID that the client or proxy device needs to join. The FA Server then creates the requested C-VID and I-SID on its device. It then responds with a PDU (containing the FA-specific TLV) to indicate whether the request succeeded. The I-SID thus created is a ELAN I-SID with endpoints of type Switched UNI. After I-SID creation, the I-SID is also advertised to the SPB network by IS-IS.
The traffic that is sent to or received from the SPB cloud is MAC-in-MAC (MiM) encapsulated. The FA Server, being SPB-capable, decapsulates the MiM traffic. If the I-SID matches the I-SID created on behalf of the client or proxy, the FA Server sends the traffic to that client or proxy and passes it on the C-VID that it expects.
An FA Server can be configured at two levels—global and interface.
Configuration at the global level enables or disables FA on the entire switch. However, for attachment of clients or proxy devices, you must also configure FA at the interface level. Interfaces can be ports (including channelized ports), MLTs, SMLT or LACP MLTs. Enabling FA on an interface also enables transmission of LLDP packets that contain the FA-specific TLVs.
When you disable FA on an interface, LLDP transmission automatically stops on that interface.
Caution
Disabling FA or IS-IS triggers a flush of FA information on the switch. Disabling FA at the global level flushes all FA element-discovery information and mappings. Disabling at the interface level flushes element-discovery information and mappings associated with that interface.
Important
The only provisioning mode supported on the FA Server is SPB.