How A Cluster Works - H3C S3610-28P Operation Manual

Operation Manual – Cluster Management
H3C S3610&S5510 Series Ethernet Switches
Candidate device: A device that does not belong to any cluster but can be added
to a cluster. Different from a member device, its topology information has been
collected by the management device but it has not been added to the cluster.
Figure 1-2 Role change in a cluster
A device in a cluster changes its role according to the following rules:
A candidate device becomes a management device when you create a cluster on
it. Note that a cluster must have one (and only one) management device. On
becoming a management device, the device collects network topology information
and tries to discover and determine candidate devices, which can then be added
to the cluster through configuration.
A candidate device becomes a member device after being added to a cluster.
A member device becomes a candidate device after it is removed from the cluster.
A management device becomes a candidate device only after the cluster is
removed.

1.1.3 How a Cluster Works

HGMPv2 consists of the following three protocols:
Neighbor Discovery Protocol (NDP)
Neighbor Topology Discovery Protocol (NTDP)
Cluster
A cluster configures and manages the devices in it through the above three protocols.
Cluster management involves topology information collection and the establishment
and maintenance of a cluster. Topology information collection and cluster maintenance
are independent from each other, with the former starting before the cluster is created:
All devices use NDP to collect the information of the directly connected neighbors,
including their software version, host name, MAC address and port number.
The management device uses NTDP to collect the information of the devices
within user-specified hops and the topology information of all devices and specify
the candidate devices of the cluster.
Chapter 1 Cluster Management Configuration
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