HP-UX LAN Administrator's Guide (July 2003)

DRAFT COPY Troubleshooting HP-UX LAN
Troubleshooting Q & A
Chapter 4 43
When high-performance systems are placed on a LAN with lower-performancesystems (HP or
non-HP systems), it is possible for the high-performance systems to use a higher percentage of
the LAN bandwidth with network traffic intensive applications. High-performance systems
generate network traffic at a 10Mbits/s link rate, and lower-performance systems cannot
match this rate. Heavily loaded LAN networks can result in lower throughput performance on
lower-performance systems.
In general, the short term average load on an IEEE802.3/Ethernet LAN should not exceed
more than 70% of the total bandwidth of the LAN. When it does exceed 70% of the total
bandwidth, network performance begins to degrade due to an increase in collisions and
deferred transmissions. When it consistently exceeds 70% of the total bandwidth, you may
need to reconfigure the systems on your LAN. If you notice throughput/performance
degradation on your system, contact your local HP Representative for additional assistance
and consultation.
“No such interface”: After I booted my server, I found that networking failed. I found the
following error in the /var/adm/rc.log file:
ifconfig lan0: no such interface
How do I resolve this problem?
Answer: This problem is caused by the LAN driver software disabling the LAN card because it
was not connected to the LAN, or the LAN was down. Use lanadmin to reset the LAN card
and run ifconfig to bring the card up.
“No such interface”: When I configure an interface, ifconfig returns the error “no such
interface.” What should I do?
Answer: The numeric portion of the interface name is incorrect. Run the lanscan command to
obtain a list of interface names.
“Plumbing error”: When I configure an interface, ifconfig returns a “Plumbing error”
message. What should I look for?
Answer: The interface name specified in the ifconfig run string is not defined in the /dev
directory or is not a streams driver. The network device files /dev/ip and /dev/tcp are not
defined.
Can’t communicate outside local supernet: I recently tried to set up a supernet on my
LAN. The systems in the supernet can communicate with one another, but they cannot
communicate with systems outside the supernet.
Answer: Check the routing table on your system and the node you want to communicate with.
If the system you want to communicate with does not support supernetting, you will have to
configure a network route for each of the networks in the supernet. If the system you want to
communicate with supports supernetting, you will only need to add a network route for the
supernet.