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30 BigIron RX Series Configuration Guide
53-1001810-01
How management module redundancy works
3
Management sessions
You can establish management sessions with the active management module’s management port.
If a switchover occurs, the management port on the original active module shuts down and all open
CLI, Web management interface, and
IronView Network Manager sessions with that port close. You
can open new sessions with the new active module, provided that the new active module has the
same management port connections. (For example, if you were accessing the Web management
interface through a PC connected to the original active module’s management port, you can open a
new session if a PC is connected to the new active module’s management port.)
In the scenario described above, you can open a new session using the same IP address you were
using before the switchover. (You configure an IP address for the active module only; if a switchover
occurs, the IP address is used by the new active module.)
Syslog and SNMP traps
When a switchover occurs, the BigIron RX system sends a Syslog message to the local Syslog buffer
and also to the Syslog server, if you have configured the system to use one. In addition, if you have
configured an SNMP trap receiver, the system sends an SNMP trap to the receiver.
When the system is powered on or otherwise reset normally, the system sends a cold start
message and trap. However, if the system is reset as the result of switchover to the standby
management module, the system instead sends a warm start message and trap.
MAC address changes
The MAC addresses in theBigIron RX Series system are based on the MAC address of the BigIron
RX Series chassis. 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 system’s new MAC addresses.
Layer 2 Hitless Failover
The Layer 2 Hitless Failover feature provides automatic failover from the active management
module to the standby management module without interrupting operation of any interface
modules in the chassis. Configuration changes made from the CLI to the active management
module are also written to the standby management module even if they are not written to flash
memory.
NOTE
Since both the standby and active management modules run the same code, a command that
brings down the active management module will most likely bring down the standby management
module. Because all configuration commands are synchronized from active to standby
management module in real time, both management modules will crash at almost the same time.
This in turn causes the system to reset all interface modules (similar to the behavior when the
'reboot' command is executed) and causes packet loss associated with a system reboot.
Once booted, the redundant management module keeps up-to-date copies of the active module's
running configuration. Layer 2 protocols such as STP, RSTP, MRP, and VSRP are run concurrently on
both the active and standby management modules. Upon the failover of the active management
module, the standby module takes over as the active management module and picks up where the
active module left off, without interrupting any Layer 2 traffic.