Summary
NIC flapping - the NIC port going in and out of bypass mode - can happen for various reasons, including increased load in the device, auto negotiation failure and bad cables.Overview
When interfaces on the Exinda flap, they go to bypass mode. Hence not breaking the network.Cause
Users might experience interfaces flapping on the Exinda for the following reasons:1. High Memory Usage on the appliance
3. Bad cables causing link connectivity issues
4. Adjacent devices port flapping
5. STP (Spanning tree protocol)
6. Huge load of traffic
7. Port faulty on the Exinda
Resolution
For 1) - A simple reboot can fix the issue. Reboot the Exinda and if possible drain the power for 10-15 minutes. During this time, the NICs are in bypass mode hence no loss of network connectivity is seen. If the Memory use is continuously high follow the article: High Memory Usage. Is this an Issue?
For 2, 3 - Check the negotiation settings and cabling. Negotiation should be the same across all the devices. Exinda to switch is a straight cable and Exinda to router is a cross cable.
For 4 - Check the NIC health on the adjacent units. If the interface flap originated on the router/switch, then Exinda is not the cause of the flaps
For 5 - We recommend to disable STP on the port connected to Exinda.
For 6 - Traffic trends causing the NIC to flap. If the appliance is being overworked and the data rate is very high, the processes concerning the NIC might get over-whelmed causing the interfaces to flap
For 7 - If none of the above apply, then we look for NIC errors on the Exinda ?