This chapter describes how to troubleshoot your switch, primarily from a hardware perspective. You can perform
more in-depth troubleshooting on the switch using the software tools available with the switch. Included are the
console interface and the built-in web browser interface. Other tools include AirWave and the Intelligent
Management Center (IMC, which is the SNMP-based network management tool). For more information, see the
“Troubleshooting” chapter in the Management and Configuration Guide for your switch, which is on the Hewlett
Packard Enterprise website at https://www.hpe.com/networking/ResourceFinder.
This chapter describes the following:
• Basic troubleshooting tips on page 68
• Diagnosing with the LEDs on page 69
• Proactive networking on page 78
• Hardware diagnostic tests on page 79
• Restoring the factory default configuration on page 80
• Downloading new switch software on page 80
Basic troubleshooting tips
Most problems are caused by the following situations. Check for these items first when starting your
troubleshooting:
• Connecting to devices that have a fixed full-duplex configuration: The RJ-45 ports are configured as
“Auto”. That is, when connecting to attached devices, the switch will operate in one of two ways to determine
the link speed and the communication mode (half duplex or full duplex):
◦ If the connected device is also configured to Auto, the switch will automatically negotiate both link speed
and communication mode.
◦ If the connected device has a fixed configuration, for example 100 Mbps, at half or full duplex, the switch
will automatically sense the link speed, but will default to a communication mode of half duplex.
Because the switch behaves in this way (in compliance with the IEEE 802.3 standard), if a device connected to
the switch has a fixed configuration at full duplex, the device will not connect correctly to the switch. The result
will be high error rates and very inefficient communications between the switch and the device.
Make sure that all the devices connected to the switch are configured to auto negotiate, or are configured to
speed and duplex settings matching those configured on the corresponding switch port.
• Faulty or loose cables: Look for loose or obviously faulty connections. If they appear to be OK, make sure
the connections are snug. If that does not correct the problem, try a different cable.
• Non-standard cables: Non-standard and incorrectly-wired cables may cause network collisions and other
network problems, and can seriously impair network performance. A category 5 or greater cable tester is a
recommended tool for every 100Base-TX and 1000Base-T network installation.
• Check the port configuration: A port on your switch may not be operating as expected because it is
administratively disabled in the configuration. It may also be placed into a “blocking” state by a protocol
Chapter 6
Troubleshooting
68 Aruba 2930M Switches
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