HP 8000M - Manual (Page 257)

8-5
Troubleshooting
Unusual Network Activity
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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 measured with the switch console interface or with 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 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 inad-
vertently create a number of redundant links that will cause broadcast
storms.
• Turn on Spanning Tree Protocol to block 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
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 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.