•Unassign all networks from the port in "loop detected" state

The SNMP agent supports trap generation when a loop condition is detected or cleared.

Virtual Connect provides the ability to enable or disable network loop protection. The feature is enabled by default and applies to all VC-Enet modules in the domain. Network loops are detected and server ports can be disabled even prior to any enclosure being imported.

A loop-protect reset command resets and restarts loop detection for all server ports in a “loop-detected” error condition.

Pause flood protection

Ethernet switch interfaces use pause frame-based flow control mechanisms to control data flow. When a pause frame is received on a flow control enabled interface, the transmit operation is stopped for the pause duration specified in the pause frame. All other frames destined for this interface are queued up. If another pause frame is received before the previous pause timer expires, the pause timer is refreshed to the new pause duration value. If a steady stream of pause frames is received for extended periods of time, the transmit queue for that interface continues to grow until all queuing resources are exhausted. This condition severely impacts the switch operation on other interfaces. In addition, all protocol operations on the switch are impacted because of the inability to transmit protocol frames. Pause frames and priority-based pause frames can cause the same resource exhaustion condition.

VC provides the ability to monitor server downlink ports, module uplink ports, and stacking links for pause flood conditions:

•If a pause flood condition is detected on a server downlink port, VC can take protective action by disabling the flooded port if pause flood protection is enabled.

•If a pause flood condition is detected on a stacking link or an uplink port, VC only reports that the pause flood condition was detected.

When the pause flood protection feature is enabled, this feature detects pause flood conditions on server downlink ports and disables the port. This feature operates at the physical port level. The port remains disabled until an administrative action is taken. When a pause flood condition is detected on a Flex-10 physical port, all Flex-10 logical ports associated with physical ports are disabled.

The administrative action involves the following steps:

1.Resolve the issue with the NIC on the server causing the continuous pause generation.

This might include updating the NIC firmware and device drivers. For information on firmware updates, see the server support documentation.

Rebooting the server might not clear the pause flood condition if the cause of the pause flood condition is in the NIC firmware. In this case, the server must be completely disconnected from the power source to reset the NIC firmware. To perform a server reboot with power disconnection:

a.Shut down the server.

b.Log in to Onboard Administrator with Administrator privileges using the OA CLI.

c.Enter the command reset server x, where [x=bay number].

d.Confirm that you want to reset the server blade.

2.Re-enable the disabled ports on the VC interconnect modules using one of the following methods:

oClick Re-enable Ports in the GUI.

oUse the "reset port-protect" CLI command.

Virtual Connect networks 101