HP OneView - Manual (Page 153)

The SNMP agent supports trap generation when a loop condition is detected or cleared.
You can reset loop protection from the Actions menu on the Interconnects screen.
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. Both port pause and priority-based pause frames can cause
the same resource exhaustion condition.
HP Virtual Connect interconnects provide the ability to monitor server downlink ports for pause
flood conditions and take protective action by disabling the port. The default polling interval is 10
seconds and is not customer configurable. The SNMP agent supports trap generation when a
pause flood condition is detected or cleared.
This feature operates at the physical port level. When a pause flood condition is detected on a
Flex-10 physical port, all Flex-10 logical ports associated with physical ports are disabled. When
the pause flood protection feature is enabled, this feature detects pause flood conditions on server
downlink ports and disables the port. The port remains disabled until an administrative action is
taken. 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.
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.
2. Re-enable the disabled ports on the HP Virtual Connect interconnect modules.
You can reset pause flood protection from the Actions menu on the Interconnects screen.
19.2.7 About SNMP settings
Network management systems use SNMP (Simple Network Management Protocol) to monitor
network-attached devices for conditions that require administrative attention. By configuring settings
on the Logical Interconnect Groups and Logical Interconnects screens, you can enable third-party
SNMP managers to monitor (read-only) network status information of the interconnects.
The SNMP manager typically manages a large number of devices, and each device can have a
large number of objects. It is impractical for the manager to poll information from every object on
every device. Instead, each agent on the managed device notifies the manager without solicitation
by sending a message known as an event trap.
The appliance enables you to control the ability of SNMP managers to read values from an
interconnect when they query for SNMP information. You can filter the type of SNMP trap to
capture, and then designate the SNMP manager to which traps will be forwarded. By default,
SNMP is enabled with no trap destinations set.
When you create a logical interconnect, it inherits the SNMP settings from its logical interconnect
group. To customize the SNMP settings at the logical interconnect level, use the Logical Interconnects
screen or REST APIs.
19.2 Managing logical interconnects and logical interconnect groups 153