3Com 7757 Configuration Manual page 705

Introduction to NTDP
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Introduction to Cluster
information is different from the existing one. Otherwise, only the holdtime of the
corresponding entry is updated.
NTDP is a protocol for network topology information collection. NTDP provides the
information about the devices that can be added to clusters and collects the
topology information within the specified hops for cluster management.
Based on the NDP information table created by NDP, NTDP transmits and forwards
NTDP topology collection request to collect the NDP information and neighboring
connection information of each device in a specific network range for the
management device or the network administrator to implement needed functions.
Upon detecting a change occurred on a neighbor, a member device informs the
management device of the change through handshake packets. The management
device then collects the specified topology information through NTDP. Such a
mechanism enables topology changes to be tracked in time.
As for NTDP implementing, you need to perform configurations on the
management device, the member devices, and the candidate devices as follows
On the management device, enable NTDP both globally and for specific ports,
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and configure the NTDP settings.
On each member device and candidate device, enable NTDP both globally and
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for specific ports. As member devices and candidate devices adopt the NTDP
settings configured for the management device, NTDP setting configurations
are not needed.
NTDP takes effect in the management VLAN only. Switch 7750 Ethernet
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switches take VLAN 1 as the management VLAN, that is, the NTDP function of
the Switch 7750 takes effect in VLAN 1 only.
Introduction to cluster configuration
A cluster has one (and only one) management device. Note the following when
creating a cluster:
You need to designate the management device first. The management device
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of a cluster is the portal of the cluster. That is, any operations performed in
external networks and intended for the member devices of a cluster, such as
accessing, configuring, managing, and monitoring, can only be implemented
through the management device.
The management device of a cluster recognizes and controls all the member
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devices in the cluster, no matter where they are located on the network or how
they are connected.
The management device collects topology information about all the member
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and candidate devices to provide useful information for users to establish a
cluster.
A management device manages and monitors the devices in the cluster by
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collecting and processing NDP/NTDP packets. NDP/NTDP packets contain
network topology information.
All the above-mentioned operations need the support of the cluster function.
Cluster Overview 705