Dell BMX01 owner manual Daisy-Chain CMC Network Connection

Condition	Description
CMC reset	Chassis management resumes after the CMC reboots or chassis fails over to the standby
	CMC.
CMC failover command	Chassis management resumes after the chassis fails over to the standby CMC.
issued
CMC firmware update	Chassis management resumes after the CMC reboots or chassis fails over to the standby
	CMC. It is recommended that you update the standby CMC first so that there is only one
	failover event. For more information on updating the CMC firmware, see the CMC User's
	Guide at support.dell.com/manuals.
CMC error detection and	Chassis management resumes after the CMC resets or chassis fails over to the standby
correction	CMC.

NOTE: You can configure the enclosure with a single CMC or with redundant CMCs. In redundant CMC configurations, if the primary CMC loses communication with the enclosure or the management network, the standby CMC takes over chassis management.

Daisy-Chain CMC Network Connection

Each CMC has two RJ-45 Ethernet ports, labeled GB (the uplink port) and STK (the stacking or cable consolidation port). With basic cabling, you can connect the GB port to the management network and leave the STK port unused.

CAUTION: Connecting the STK port to the management network can have unpredictable results. Cabling GB and STK to the same network (broadcast domain) can cause a broadcast storm.

If you have multiple chassis in a rack, you can reduce the number of connections to the management network by daisy- chaining up to four chassis together. If each of the four chassis contains a redundant CMC, by daisy-chaining you can reduce the number of management network connections required from eight to two. If each chassis has only one CMC, you can reduce the connections required from four to one.

When daisy-chaining chassis together, GB is the uplink port and STK is the stacking (cable consolidation) port. Connect the GB ports to the management network or to the STK port of the CMC in a chassis that is closer to the network. You must connect the STK port only to a GB port further from the chain or network.

Create separate chains for the CMCs in the active CMC slot and the second CMC slot.

NOTE: At least one CMC must be installed for the system to power up. If a second, optional CMC module is installed, failover protection and hot-swap replacement is available. See the latest CMC User's Guide at support.dell.com/manuals for complete instructions on how to set up and operate the CMC module.

The following figure illustrates the arrangement of cables for four daisy-chained chassis, each with active and standby CMCs.

20