Path Protection
The spine leaf architecture in the cluster environment provides failover for the following:
| • | leaf node failure. Refer to Leaf Node Failure. |
| • | stack link failure on a leaf node (not connected to a tool, but can be connected to a network TAP). Refer to Stack Link Failure on Leaf (TAP Connected). |
| • | spine node failure. Refer to Spine Node Failure. |
| • | stack link failure on a leaf node (connected to a tool). Refer to Stack Link Failure on Leaf (Tool Connected). |
Leaf Node Failure
Refer to Figure 1 Leaf Node Failure for a failure in which a leaf node is powered down or rebooted. The leaf node does not have a connected TAP or tool.
Note: In the following figures, red arrows indicate traffic direction.
With this type of failure, the stack links connected to the affected leaf node go down, which will be detected by the spine nodes. No action will be required at the spine nodes. Since the links are down, no traffic will be sent to the affected leaf node.
| Figure 30 | Leaf Node Failure |
Restoration
Once the leaf node is powered up and booted, it will restore its traffic configuration.
Affected Time
None. Traffic on other leaf nodes will not be affected.
Stack Link Failure on Leaf (TAP Connected)
Refer to Figure 2 Stack Link Failure on Leaf (TAP Connected) for a failure in which a stack link on a leaf node fails and the leaf node is connected only to a TAP.
With this type of failure, the stack link between the leaf and spine nodes goes down. No action will be required at the spine node. At the leaf node, the affected link will be removed from the stack GigaStream. Traffic will be sent to the other spine node.
| Figure 31 | Stack Link Failure on Leaf (TAP Connected) |
Restoration
When the link comes back up, the leaf node will put the link back into the GigaStream.
Affected Time
When the link is down, traffic recovers in a similar amount of time as a tool GigaStream.
Spine Node Failure
Refer to Figure 3 Spine Node Failure for a failure in which a spine node is powered down or rebooted.
With this type of failure, the stack link between the leaf and spine nodes goes down. The leaf nodes will detect that the stack link is down. The affected link will be removed from the stack GigaStream. Traffic will be load balanced to the other spine node.
| Figure 32 | Spine Node Failure |
Restoration
When the spine node reboots, the cluster will synchronize. When the node converges to the cluster and the configuration synchronizes, traffic will be restored.
Affected Time
When the spine node is powered down or rebooted, traffic recovers in a similar amount of time as a tool GigaStream.
Stack Link Failure on Leaf (Tool Connected)
Refer to Figure 4 Stack Link Failure on Leaf (Tool Connected) for a failure in which a stack link between the leaf and spine nodes fails and the leaf node is connected to a tool.
In the current software version, this type of failure is not supported.
| Figure 33 | Stack Link Failure on Leaf (Tool Connected) |
Document INFORMATION 
