3Com CoreBuilder 9000 Quick Start Manual page 14

14 Enterprise Management Engine Quick Start Guide
Redundancy Adding a second EME in slot 9 in the 7-slot chassis, slot 10 in the 8-slot
chassis, and slot 18 in the 16-slot chassis establishes Redundancy.
Redundancy provides standby support in case the first, or primary, EME
fails for any reason. The standby, or secondary, EME learns configuration
information from the primary EME and takes over management and
controller responsibility if the primary EME fails.
The command lists the status of the management
show module all
modules in the chassis (EMEs and EMCs), including which EME is the
primary and which EME is the secondary.
The slot location for each EME determines the redundancy status. If you
EME Redundancy
Status
install the first EME in slot 8 of the 7-slot chassis, slot 9 of the 8-slot
chassis, or slot 17 of a 16-slot chassis, its status is displayed as
primary
after you enter a command. The primary EME has
show module all
configuration control, management responsibilities, and fault detection
capabilities for the entire CoreBuilder 9000 Enterprise Switch.
After you install a second EME in the adjacent slot in each chassis, its
status is displayed as after you enter a
secondary show module all
command.
3Com recommends that you always install the first EME in the
lower-numbered slot, then install the second EME in the adjacent slot
after the first EME has initialized.