3Com 5500-EI PWR Install Manual page 760

device to Active; otherwise, it changes the state of the member device (in Connect state) to
Disconnect, in which case the management device considers the member device disconnected.
Likewise, if this member device, which is in Connect state, receives a handshake packet or
management packet from the management device within the information holdtime, it changes its
state to Active; otherwise, it changes its state to Disconnect.
If the connection between the management device and a member device in Disconnect state is
recovered, the member device will be added to the cluster again. After that, the state of the
member device will turn to Active both locally and on the management device.
Besides, handshake packets are also used by member devices to inform the management device of
topology changes.
Additionally, on the management device, you can configure the FTP server, TFTP server, logging host
and SNMP host to be shared by the whole cluster. When a member device in the cluster communicates
with an external server, the member device first transmits data to the management device, which then
forwards the data to the external server. The management device is the default shared FTP/TFTP
server for the cluster; it serves as the shared FTP/TFTP server when no shared FTP/TFTP server is
configured for the cluster.
Management VLAN
Management VLAN limits the range of cluster management. Through management VLAN configuration,
the following functions can be implemented:
Enabling the management packets (including NDP packets, NTDP packets, and handshake
packets) to be transmitted in the management VLAN only, through which the management packets
are isolated from other packets and network security is improved.
Enabling the management device and the member devices to communicate with each other in the
management VLAN.
Cluster management requires the packets of the management VLAN be permitted on ports connecting
the management device and the member/candidate devices. Therefore:
If the packets of management VLAN are not permitted on a candidate device port connecting to the
management device, the candidate device cannot be added to the cluster. In this case, you can
enable the packets of the management VLAN to be permitted on the port through the management
VLAN auto-negotiation function.
Packets of the management VLAN can be exchanged between the management device and a
member device/candidate device without carrying VLAN tags only when the default VLAN ID of
both the two ports connecting the management device and the member/candidate device is the
management VLAN. If the VLAN IDs of the both sides are not that of the management VLAN,
packets of the management VLAN need to be tagged.
By default, the management VLAN interface is used as the network management interface.
There is only one network management interface on a management device; any newly configured
network management interface will overwrite the old one.
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