Installing and Administering LAN/9000 Software

Chapter 4 77
Troubleshooting LAN/9000
100Base-T Checklist
100Base-T Checklist
In case of trouble with 100Base-T LAN links, you can use the following
procedures to troubleshoot your network problems:
• Verify Cabling: make sure the connection is secured, UTP Category 5
is used, the card is well inserted. Also, assure the cable length is not
within 35 - 41 meters. Check the cable running from the HP adapter
to the Switch, and the Switch port, in case either is defective.
— If the cable length is between 35 - 41 meters, (or 114 - 133 feet),
then expand or reduce the length so that the cable is less than 35
meters or greater than 41 meters, keeping within 100Base-T
specifications.
— Have your site technician verify that the pair assignments and
color codes of the RJ45 connector pins match the following
recommended version:
— Receive Signal: pin 1 = White and pin 2 = Orange
— Transmit Signal: pin 3 = White and pin 6 = Green
— Double-check your existing punch-down blocks in your networking
environment. Punch-down blocks may affect the characteristics of
the medium and therefore the problem seen with the 35-41 meter
length cable may vary in length.
— Some visible symptoms that might occur when the cable length is
between 35 - 41 meters are:
— Link Status is Down: LED light color turns amber because card
negotiating with switch defaults to 10Mb/s instead of 100Mb/s.
Or the LED lights are intermittent between 10Mb/s and
100Mb/s. They blink between 10Mb/s and 100Mb/s and keep
doing that.
— There is no traffic or there is high rate of packet loss.
— To verify if the link is not yet established, format log file using
the following command and syntax:
netfmt -LN -f /var/adm/nettt.LOG* > outfile
Once the nettl log file is formatted, look for a string such as