1-4z A management device becomes a candidate device only after the cluster is removed.After you create a cluster on an S5600 switch, the switch collects the network topology informationperiodically and adds the candidate switches it finds to the cluster. The interval for a managementdevice to collect network topology information is determined by the NTDP timer. If you do not want thecandidate switches to be added to a cluster automatically, you can set the topology collection interval to0 by using the ntdp timer command. In this case, the switch does not collect network topologyinformation periodically.How a Cluster WorksHGMPv2 consists of the following three protocols:z Neighbor Discovery Protocol (NDP)z Neighbor Topology Discovery Protocol (NTDP)z ClusterA cluster configures and manages the devices in it through the above three protocols.Cluster management involves topology information collection and the establishment/maintenance of acluster. Topology information collection and cluster establishment/maintenance are independent fromeach other. The former, as described below, starts before a cluster is established.z All devices use NDP to collect the information about their neighbors, including software version,host name, MAC address, and port name.z The management device uses NTDP to collect the information about the devices within specifichops and the topology information about the devices. It also determines the candidate devicesaccording to the information collected.z The management device adds the candidate devices to the cluster or removes member devicesfrom the cluster according to the candidate device information collected through NTDP.Introduction to NDPNDP is a protocol used to discover adjacent devices and provide information about them. NDP operateson the data link layer, and therefore it supports different network layer protocols.NDP is able to discover directly connected neighbors and provide the following neighbor information:device type, software/hardware version, and connecting port. In addition, it may provide the followingneighbor information: device ID, port full/half duplex mode, product version, the Boot ROM version andso on.z An NDP-enabled device maintains an NDP neighbor table. Each entry in the NDP table canautomatically ages out. You can also clear the current NDP information manually to have neighborinformation collected again.z An NDP-enabled device regularly broadcasts NDP packet through all its active ports. An NDPpacket carries a holdtime field, which indicates how long the receiving devices will keep the NDPpacket data. The receiving devices store the information carried in the NDP packet into the NDPtable but do not forward the NDP packet. When they receive another NDP packet, if the information
