Switchover; Management Sessions; Syslog And Snmp Traps; Mac Address Changes - HP ProCurve 9304M Installation And Configuration Manual

Installation and Basic Configuration Guide

Switchover

When you power on or reload a Chassis device that contains two redundant management modules, the active
redundant management module is selected based on the chassis slot previously specified by you or according to
the lower slot number.
After the active module is selected, the active module loads its boot and flash code (boot and system software)
and its system-config file and manages the system. The standby module also boots, using its own boot code but
using the active module's flash code and system-config file. The standby module monitors the heartbeat of the
active module. If the active module becomes unavailable, the standby module notices the absence of the
heartbeat and assumes management control of the system.
NOTE: By default, the system does not use the boot code on the active module to boot the standby module. If
you upgrade the boot code on the active module and the code contains a problem, you can still use the system by
running the older boot code that is on the standby module. You can configure the standby to synchronize with the
active module's boot code. See "File Synchronization Between the Active and Standby Redundant Management
Modules" on page 3-10.
The standby module's system-config file is updated whenever the system-config file on the active module is
updated. In addition, the running-config file on the standby module is updated at regular intervals to match the
active module's running-config data. Thus, when a switchover occurs, the standby module also can reinstate the
configuration data in the active module's running-config.
Following this switchover to the standby module, the standby module becomes the active module and continues to
manage the system. When the other redundant management module (the one that used to be the active module)
becomes available again or is replaced, that module becomes the standby module.
The active module also monitors the standby module. If the standby module becomes unavailable, the active
module tries to reboot the standby module. You can display the status of each module using the CLI or the Web
management interface, as described in "Determining Redundant Management Module Status" on page 3-7.

Management Sessions

You can establish management sessions only with the active redundant management module, not with the
standby redundant management module. During switchover, all the CLI, Web management interface, and SNMP
management application sessions open on the system are closed. To manage the system following a switchover,
you must open a new management session. Although the system's MAC addresses change following switchover,
the IP addresses do not. You can open new management sessions on the same IP addresses you were using
before the switchover if desired.
To establish a serial connection to the CLI, you must move the serial cable to the serial port on the active
redundant management module.

Syslog and SNMP Traps

When a switchover occurs, the software sends a Syslog message to the local Syslog buffer and also to the Syslog
server, if you have configured the HP device to use one. In addition, if you have configured an SNMP trap
receiver, the software sends an SNMP trap to the receiver.
When the system is powered on or otherwise reset normally, the software sends a cold start message and trap.
However, if the system is reset as the result of switchover to the standby redundant management module, the
software instead sends a switchover message and trap.

MAC Address Changes

The MAC addresses in the system are based on the MAC address of the active management module. During
switchover, the system's MAC addresses change and the system sends out gratuitous ARP requests to flush the
old MAC addresses from the ARP caches on attached IP devices, and update the caches with the HP device's
new MAC addresses.
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