Fabric Attach

Table 1. Fabric Attach product support

Feature	Product	Release introduced
Fabric Attach Server	5320 Series	Fabric Engine 8.6
	5420 Series	VOSS 8.4
	5520 Series	VOSS 8.2.5
	5720 Series	Fabric Engine 8.7
	7520 Series	Fabric Engine 8.10
	7720 Series	Fabric Engine 8.10
	VSP 4450 Series	VOSS 5.0
	VSP 4900 Series	VOSS 8.1
	VSP 7200 Series	VOSS 5.0
	VSP 7400 Series	VOSS 8.0
	VSP 8200 Series	VOSS 5.0
	VSP 8400 Series	VOSS 5.0
	VSP 8600 Series	VSP 8600 6.3
	XA1400 Series	Not Supported

With Fabric Attach, network edge devices that do not support Shortest Path Bridging (SPB), MAC-in-MAC encapsulation (802.1ah) or service identifiers (I-SIDs) can take advantage of SPB infrastructure. To attach to an SPB network, edge devices signal an SPB-aware FA Server to automatically configure the I-SIDs. The edge devices can then utilize existing SPB features across the fabric and leverage SPB infrastructure capabilities without manual configuration. Fabric Attach uses the IEEE 802.1AB Logical Link Discovery Protocol (LLDP) to signal a desire to join the SPB network.

FA uses the client-server model. An initial handshake occurs between the FA Server and the FA Client. After the discovery phase is complete, the FA Server accepts requests (from FA Clients) to add the C-VID (VLAN ID) and I-SID elements in the SPB network, and also automatically configures the necessary C-VID and I-SID. The FA Server then responds with an acknowledgement of whether the request succeeded. FA Clients can also be aggregated into a proxy device that handles the handshakes and requests on behalf of many clients, to the server. All of the discovery handshakes and I-SID mapping requests are then transferred using LLDP Type, Length, Value (TLV) fields.

FA leverages LLDP to discover directly connected FA peers and to exchange information associated with FA between those peers. Based on the LLDP standard, FA information is transmitted using organizational TLVs within LLDP Protocol Data Units (PDU).