3Com Switch 7750 Configuration Guide

Cluster Overview 707
The switch roles are switched according to the following rules:
Figure 183 Role switching roles
■ Each cluster has one (and only one) management device. A management
device collects NDP/NTDP information to discover and determine candidate
devices, which can be then added into the cluster through manual
configurations.
■ A candidate device becomes a member device after being added to a cluster.
Table 563 Switch roles in the cluster
Role Configuration Description
Management device
■ Configured with a public IP
address.
■ Receive management
commands that a user sends
through the public network
and process the received
commands
■ Provide management interfaces
for all switches in the cluster
■ Manage member devices by
redirecting commands, that is,
forward the commands to the
intended member devices for
processing
■ Provide the following
functions, including neighbor
discovery, topology
information collection, cluster
management, and cluster state
maintenance, and support all
types of FTP servers and SNMP
host proxies
Member device Normally, a member device is not
configured with a public IP
address
■ Member in the cluster
■ Neighbor discovery, being
managed by the management
device, running commands
forwarded by proxies, and
failure/log reporting
Candidate device Normally, a candidate device is
not configured with a public IP
address
A candidate device is a switch that
does not belong to any cluster,
although it can be added to a
cluster
Candidate device
Member device
Management device
D
e
s
ig
nated as a manag
e
m
en
tde
v
ice
A
dd
ed to a cl
u
s
t
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r
R
e
m
o
ve
d
from
a
clust
e
r
Remov
e
d
f
rom a
c
lu
s
ter