H3C Technologies H3C S5120 Series Switches - Manual (Page 676)

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z On the same device, except the first port, each NTDP-enabled port waits for a period of time and
then forwards the NTDP topology collection request after its prior port forwards the NTDP topology
collection request.
Cluster management maintenance
1) Adding a candidate device to a cluster
You should specify the management device before creating a cluster. The management device
discovers and defines a candidate device through NDP and NTDP protocols. The candidate device can
be automatically or manually added to the cluster.
After the candidate device is added to the cluster, it can obtain the member number assigned by the
management device and the private IP address used for cluster management.
2) Communication within a cluster
In a cluster the management device communicates with its member devices by sending handshake
packets to maintain connection between them. The management/member device state change is
shown in Figure 1-3 .
Figure 1-3 Management/member device state change
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Active
Disconnect Connect
z After a cluster is created, a candidate device is added to the cluster and becomes a member device,
the management device saves the state information of its member device and identifies it as Active.
And the member device also saves its state information and identifies itself as Active.
z After a cluster is created, its management device and member devices begin to send handshake
packets. Upon receiving the handshake packets from the other side, the management device or a
member device simply remains its state as Active, without sending a response.
z If the management device does not receive the handshake packets from a member device in an
interval three times of the interval to send handshake packets, it changes the status of the member
device from Active to Connect. Likewise, if a member device fails to receive the handshake packets
from the management device in an interval three times of the interval to send handshake packets,
the status of itself will also be changed from Active to Connect.
z If this management device, in information holdtime, receives the handshake or management
packets from its member device which is in Connect state, it changes the state of its member
device to Active; otherwise, it changes the state of its member device to Disconnect, in which case
the management device considers its member device disconnected. If this member device, which
is in Connect state, receives handshake or management packets from the management device in