Server Management Guide

Baseboard Management Controller
34 Intel
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Server Boards and Server Platforms Server Management Guide
 BMC LAN channel 3 (RMM) MAC address = NIC1 MAC address + 6.
2.6.4 BMC LAN Failover
The BMC firmware provides a LAN failover capability such that the failure of the system HW associated
with one LAN link will result in traffic being rerouted to an alternate link. This functionality is
configurable through IPMI methods as well as through the BMC’s embedded user interface. BMC will
support only an all or nothing” approach – that is, all interfaces bonded together, or none are
bonded together.
The LAN Failover feature applies only to BMC LAN traffic. It bonds all available Ethernet devices but
only one is active at a time. When enabled, If the active connection’s leash is lost, one of the secondary
connections is automatically configured so that it has the same IP address (the next active LAN link will
be chosen randomly from the pool of backup LAN links with link status as “UP”). Traffic immediately
resumes on the new active connection.
The LAN Failover enable/disable command may be sent at any time. After it has been enabled, standard
IPMI commands for setting channel configuration that specify a LAN channel other than the first LAN
channel will return an error code. Standard IPMI commands for getting channel configuration will return
the cached settings for the inactive channels.
There will be no notification when there has been a failover to a different LAN channel. In addition,
there is no indication of which LAN channel is currently being used. The BMC does not keep track of
channels that it has previously failed over from so if there is a second failover it could potentially go
back to a previously failed channel, if that channel has been restored to full functionality.
2.6.4.1 Setting up BMC LAN Failover
When LAN failover gets enabled the settings for the first LAN channel will be used. If enabling LAN
failover remotely it is suggested that you setup the first LAN channel with the required settings (DHCP or
Static with IP Address, Net Mask and Gateway) before you enable LAN failover. Otherwise, you will
lose connectivity and be unable to remotely set the first LAN channel configuration. As soon as LAN
failover is enabled it will start using the first LAN channels settings.
The configuration for LAN channels 2 and 3 are irrelevant when LAN failover is enabled. They are
available so that the administrator can see that the configuration has not been lost and will be reinstituted
if LAN failover is disabled.
NOTE
When LAN failover is enabled the system administrator should ensure that all LAN connections that
can be seen by the BMC have connectivity to the same networks. If there is a loss of functionality on
the primary LAN channel it can randomly failover to any of the other LAN channels that are connected
and seen by the BMC.