Fujitsu PRIMEQUEST 480 System Design Manual page 183

Remarks: At least one optional BMM is required per partition. If no BMM is
Redundancy of the private LAN
An intra-cabinet LAN referred to as a private LAN connects MMBs and BMCs. A
BMC has a LAN interface for a 100 Mbps private LAN for each redundant MMB.
The MMB includes a hub for terminating a 100 Mbps LAN signal from a BMC. The
private LAN, used to link MMBs to BMCs, is duplicated according to the duplication
of MMBs. The system is configured such that it can operate without any problem in
the event of a failure on either side of a connection.
Redundancy of the management LAN
An management LAN is used to connect an external device of PRIMEQUEST series
machines to partitions in the PRIMEQUEST, and to connect partitions in the
PRIMEQUEST to one another. An management LAN is intended for critical system
management tasks, such as connection to a console unit (such as a general-purpose
PC) and node-to-node connection in a cluster configuration. In the same way as for a
private LAN, a hub incorporated in an MMB connects the components in a cabinet.
CPUs of an MMB are also connected to an management LAN. An management LAN
has three external interface ports. Two ports are allocated for maintenance tasks
performed by Fujitsu certified service engineers and REMCS. The remaining port
can be used to connect to a console unit, or for connection between nodes across
cabinets in a cluster configuration. An management LAN, as in the case of a private
LAN, is duplicated according to the duplication of MMBs. The system is configured
such that it can operate without any problem in the event of a failure on either side of
a connection.
Example of automatic switching at an MMB failure
Redundant configuration is adopted for MMBs. Therefore, there are two
management LAN interfaces for MMBs in the entire system. A virtual IP address to
be shared is assigned to each of the management LAN interfaces. If MMBs are
switched due to an MMB failure, the virtual IP address is inherited and the
communication destination unit can continue operation without having to take the
MMB status into consideration.
C122-B001-02EN
mounted in any of IO_Units that are used to configure a partition, the
partition does not work. If multiple BMMs exist in a partition, the
specified BMM (specified from the MMB Web-UI as the home IO_Unit)
operates.
6.2 Redundancy of Private LAN and Management LAN
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