Symptoms:

• All Switch port LED are on solid
• Network is down
• Broadcast Storm
• ARP Storm

Facts:

• Switch 4050
• Switch 4060
• Switch 4007
• Switch 4005
• SuperStack 3 Switch 3300
• SuperStack 3 Switch 4200
• SuperStack 3 Switch 4300
• SuperStack 3 Switch 4400
• SuperStack 3 Baseline Switch
• SuperStack 3 Switch 4900
• SuperStack II Switch 3300
• SuperStack II Switch 3900
• SuperStack II Switch 9300
• Flat Layer 2 Network

Causes: A Broadcast Storm or ARP Storm can be created on a flat Layer 2 Network if

• A) A Bridging Loop is created in the network and Spanning Tree Protocol is disabled;
• B) If Spanning Tree is Enabled and a 2 ports connected together have a Duplex mismatch on either side of the connection (this could allow BPDUs to be dropped, thus causing a blocked port to become active);
• C) A client, Printer, PC or Server has a bad NIC Card or CAT 5 Cable.

Fixes: If the problem is a redundant connection between Switches check that STP is enabled and that the appropriate port(s) are in Blocking mode or remove the redundant connection. If the problem is the latter of the 2, start disconnecting devices from the switch ports, one at a time waiting 2 -3 seconds between disconnects, leave the device disabled, and move to the next port.

Check the status of the Switch Port LEDs as you progress. The LEDs should go back to normal when the offending device is found. Connect the other disconnected devices and troubleshoot the offending device. If the task of removing devices is too laborious and time consuming using a network sniffer may be more efficient.

• Product(s): SuperStack II Switches, SuperStack 3 Switches, Switch 4005, Switch 4007, Switch 4050, Switch 4060
• Sub Product(s):

— David Gonzalez 2021/04/14 09:57