Zero Touch Fabric Configuration automatically triggers when the switch boots without a configuration file, the platform enables Intermediate System-to-Intermediate System (IS-IS) without a configured nickname or manual area. The system creates default backbone VLANs (B-VLAN) (4051 and 4052) and IS-IS manual area values. As a result, if you start two nodes in a network without an existing configuration file, then Zero Touch Fabric Configuration dynamically establishes an IS-IS adjacency between them.
The switch uses the Auto-sense functionality with the Zero Touch Fabric Configuration feature to establish the adjacency between two nodes. For more information about how and when the system tries to establish the adjacency, see Auto-sense Port States .
If you manually configure an SPBM instance on a node, then the system removes the SPBM instance that is dynamically created by Zero Touch Fabric Configuration. The system uses the LLDP Fabric Connect TLV to send user-defined B-VLANs to other nodes in the network. Only the first pair of B-VLANs is learned. If the switch already learned the B-VLANs from neighbor_A, the switch ignores the B-VLANs received from neighbor_B, if those are different.
If a switch operating in Zero Touch Fabric Configuration mode in the network receives B-VLANs from a neighboring switch, which do not match the default B-VLANs configured through Zero Touch Fabric Configuration, then the switch will perform the following actions:
Disables ISIS.
Deletes its VLANs.
Unassigns the B-VLANs.
Assigns the values received through LLDP Fabric Connect TLV.
Creates the corresponding VLANs.
Re enables ISIS and log a message on the console.
The system uses an LLDP Fabric Connect TLV to communicate B-VLANs, system IDs, Fabric Attach and EAP events between nodes in the SPB cloud.
|
TLV Type |
TLV Length |
OUI |
Subtype |
Fabric Connect Capabilities |
B-VLANs Number |
B-VLAN-1 |
B-VLAN-2 |
System ID Length |
System ID |
|---|---|---|---|---|---|---|---|---|---|
|
7 bits |
9 bits |
3 octets |
1 byte |
1 byte |
1 byte |
2 bytes |
2 bytes |
1 byte |
6 bytes |
|
TLV Field |
Description |
|---|---|
|
Fabric Connect capability |
Fabric Connect capability is enabled on all nodes that support Zero Touch Fabric Configuration. The value is 0 if the LLDP Fabric Connect TLV is not carrying any information in it. By default, the value is set to 1 on all ports. |
|
B-VLANs number |
Specifies the number of B-VLANs that the TLV can carry. The LLDP Fabric Connect TLV supports an unlimited number of B-VLANs, but Zero Touch Fabric Configuration sends 2 B-VLANs through the TLV. The value is 0 if the node is sending default B-VLAN values. |
|
B-VLANs |
Specifies the B-VLAN that is user-configured or dynamically learned from a neighbor node in the network. |
|
System ID Length |
Specifies the length (in bytes) of the System ID. |
|
System ID |
Specifies the IS-IS system ID. |
|
OUI |
Specifies the Extreme OID value (0xd88466). |