Table of Contents
Advertisement
Troubleshooting
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.
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
n
"Auto". That is, when connecting to attached devices, the switch operates in either half duplex or full duplex to
determine the link speed and the communication mode:
If the connected device is also configured to Auto, the switch will automatically negotiate both link speed and
o
communication mode.
If the connected device has a fixed configuration, for example 100 Mbps, at half or full duplex, the switch will
o
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 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 the settings configured on the corresponding switch port.
Improper Network Topologies: It is important to make sure that you have a valid network topology. Common
n
topology faults include excessive cable length and excessive repeater delays between end nodes. If you have
network problems after recent changes to the network, change back to the previous topology. If you no longer
experience the problems, the new topology is probably at fault. Sample topologies are shown at the end of
chapter 2 in this book.
In addition, make sure that your network topology contains no data path loops. Between any two end nodes, only
one active cabling path is allowed at any time. Data path loops can cause broadcast storms that will severely
impact your network performance.
For your switch, if you want to build redundant paths between important nodes in your network to provide some
fault tolerance, enable Spanning Tree Protocol support on the switch. This support ensures that only one of the
redundant paths is active at any time, thus avoiding data path loops. For more information on Spanning Tree, see
the Layer 2 Bridging Guide.
Faulty or Loose Cables: Look for loose or faulty connections. If they appear to be OK, make sure that the
n
connections are snug. If that does not correct the problem, try a different cable.
Nonstandard Cables: Nonstandard and incorrectly wired cables may cause network collisions and other
n
network problems, and can seriously impair network performance. A category 5 or greater cable tester is a
recommended tool for every network installation.
Check the Port Configuration: A port on your switch may not be operating as expected because it is
n
administratively disabled in the configuration. It may also be placed into a "blocking" state by a protocol operating
on the port (dynamic VLANs), or LACP (dynamic trunking). For example, the normal operation of the spanning
HPE Aruba Networking CX 6300 Switch Series | Installation and Getting Started Guide
Chapter 6
Troubleshooting
46
Advertisement
Table of Contents
