Network activity that fails to meet accepted norms may indicate a hardware problem with one or more of the network components, possibly including the switch. Such problems can also be caused by a network loop or simply too much traffic for the network as it is currently designed and implemented. Unusual network activity is usually indicated by the LEDs on the front of the switch or measured with the switch console interface or with a network management tool such as IMC. For information on using LEDs to identify unusual network activity, see the Installation Guide you received with the switch.
A topology loop can also cause excessive network activity. The Event Log "FFI" messages can be indicative of this type of problem.
Broadcast storms may be occurring in the network. These may be caused by redundant links between nodes.
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If you are configuring a port trunk, finish configuring the ports in the trunk before connecting the related cables. Otherwise you may inadvertently create a number of redundant links (that is, topology loops) that will cause broadcast storms.
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Turn on STP to block redundant links
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Check for FFI messages in the Event Log.
If you use a DHCP server to assign IP addresses in your network, and you find a device with a valid IP address that does not appear to communicate properly with the server or other devices, a duplicate IP address may have been issued by the server. This can occur if a client has not released a DHCP-assigned IP address after the intended expiration time and the server "leases" the address to another device. This can also happen, for example, if the server is first configured to issue IP addresses with an unlimited duration, and then is subsequently configured to issue IP addresses that will expire after a limited duration. One solution is to configure "reservations" in the DHCP server for specific IP addresses to be assigned to devices having specific MAC addresses. For more information, see the documentation for the DHCP server.
One indication of a duplicate IP address in a DHCP network is this Event Log message:
where both instances of IP-address are the same address, indicating that the IP address has been duplicated somewhere on the network.
When the switch is first configured for DHCP/Bootp operation, or if it is rebooted with this configuration, it immediately begins sending request packets on the network. If the switch does not receive a reply to its DHCP/Bootp requests, it continues to periodically send request packets, but with decreasing frequency. Thus, if a DHCP or Bootp server is not available or accessible to the switch when DHCP/Bootp is first configured, the switch may not immediately receive the desired configuration.
After verifying that the server has become accessible to the switch, reboot the switch to re-start the process.