User's Manual

Installing and Setting Up the CMC 31
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
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.
Daisy-chain CMC Network Connection
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.
Figure 2-1 illustrates the arrangement of cables for four daisy-chained chassis,
each with active and standby CMCs.