8-4
Troubleshooting
Unusual Network Activity
Troubleshooting
Unusual Network Activity
Network activity that exceeds accepted norms often indicates a hardware 
problem with one or more of the network components, possibly including the 
switch. Unusual network activity is usually indicated by the LEDs on the front 
of the switch or as indicated by measurements from the switch console or 
from a network management tool such as the HP TopTools for Hubs & 
Switches. Refer to the installation guide you received with the switch for 
information on using LEDs to identify unusual network activity.
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 due to loops in the network topology (redundant links between nodes).
• Inspect your network topology to make sure there are no loops in the 
network.
• If your network requires redundant links to guarantee maintenance 
of network connectivity, turn on Spanning Tree Protocol to maintain 
a single active path and provide for redundant links.
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 the 
IP address that has been duplicated somewhere on the network.
Duplicate IP Addresses in a DHCP Network.  If you use a DHCP server 
to automatically 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, then is subse-
quently 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, refer to the documentation for the DHCP server.
Sraswb.book : SIER_SW8.FM  Page 4  Tuesday, June 30, 1998  12:20 PM