User Guide

128.....Avocent® Universal Management Gateway Appliance Installer/User Guide
Bridge groups
When creating a bridge group inside of the appliance, there is a default setting to "Enable STP."
STP (Spanning Tree Protocol) is a network switch methodology for eliminating switching loops
caused by redundant network connections. STP requires network switches to send out a BPDU
(bridging protocol data unit) which is essentially an ID that identifies the sending switch.
All switches receive these BPDUs across all connections to that switch and compare it to their own
BPDU. If the same BPDU comes in on more than one connection, the switch determines one of
those connections to be redundant and it will disable that link. This can happen if you connect two
appliance ports to a network switch and place both of the appliance ports into a single bridge group.
Most enterprise network switches have a feature called BPDU_guard which is intended to be
enabled on ports that are not supposed to be connected to other network switches (Cisco Nexus
switches enable this feature by default on all interfaces).
If you connect an appliance to a switch with the BPDU_guard active, then you must disable STP if
you plan to create a bridge group on that appliance. If you don't disable STP, the network switch will
disable its connection to the appliance when a bridge group is created. It will do this because the
appliance will send out its own BPDU when the STP option is enabled.
Hardware
The appliance has a boot menu option to help you troubleshoot hardware issues. Choosing to boot
the appliance to its hardware diagnostics mode can quickly help you identify if it has bad memory.
To identify other types of hardware problems, issue the following shell commands using an
appliance that boots properly:
Type Command
Fan Failure cat /sys/devices/platform/dcima_hwmon.2560/fan*
Temp Issues cat /sys/devices/platform/dcima_hwmon.2560/temp*
Power Supply issues cat /sys/devices/platform/dcima_hwmon.2560/voltage*
Shell Hardware Diagnostic Commands
If the diagnostic test reveals a hardware failure, contact Avocent Technical Support. Firmware
bugs can be resolved through a clean load of firmware via the NetBoot menu or USB_boot
procedure.