Management and Configuration Guide K/KA/KB.15.15

Unusual network activity
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 switchconsole interface or with a network management tool such as HP
PCM+. 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.
General problems
The network runs slow; processes fail; users cannot access servers or other devices
Broadcast storms may be occurring in the network. These may be caused by redundant links
between nodes.
• 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.
• Turn on STP to block redundant links
• Check for FFI messages in the Event Log.
Duplicate IP addresses
This is indicated by this Event Log message:
ip: Invalid ARP source: IP address on IP address
where both instances of IP address are the same address, indicating that the
switch's IP address has been duplicated somewhere on the network.
Duplicate IP addresses in a DHCP network
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:
ip: Invalid ARP source: IP-address on IP-address
where both instances of IP-address are the same address, indicating that the IP address has
been duplicated somewhere on the network.
The switch has been configured for DHCP/Bootp operation, but has not received a DHCP or Bootp
reply
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
370 Troubleshooting