H3C S3100-52P Operation Manual page 611

Operation Manual – Stack-Cluster
H3C S3100-52P Ethernet Switch
neighbor information: device type, software/hardware version, and connecting port. In
addition, it may provide the following neighbor information: device ID, port full/half
duplex mode, product version, the Boot ROM version and so on.
An NDP-enabled device maintains an NDP neighbor table. Each entry in the NDP
table can automatically ages out. You can also clear the current NDP information
manually to have neighbor information collected again.
An NDP-enabled device regularly broadcasts NDP packet through all its active
ports. An NDP packet carries a holdtime field, which indicates how long the
receiving devices will keep the NDP packet data. The receiving devices store the
information carried in the NDP packet into the NDP table but do not forward the
NDP packet. When they receive another NDP packet, if the information carried in
the packet is different from the stored one, the corresponding entry in the NDP
table is updated, otherwise only the holdtime of the entry is updated.
II. Introduction to NTDP
NTDP is a protocol used to collect network topology information. NTDP provides
information required for cluster management: it collects topology information about the
switches within the specified hop count, so as to provide the information of which
devices can be added to a cluster.
Based on the neighbor information stored in the neighbor table maintained by NDP,
NTDP on the management device advertises NTDP topology collection requests to
collect the NDP information of each device in a specific network range as well as the
connection information of all its neighbors. The information collected will be used by the
management device or the network management software to implement required
functions.
When a member device detects a change on its neighbors through its NDP table, it
informs the management device through handshake packets, and the management
device triggers its NTDP to perform specific topology collection, so that its NTDP can
discover topology changes timely.
The management device collects the topology information periodically. You can also
launch an operation of topology information collection by executing related commands.
The process of topology information collection is as follows.
The management device sends NTDP topology collection requests periodically
through its NTDP-enabled ports.
Upon receiving an NTDP topology collection request, the device returns a NTDP
topology collection response to the management device and forwards the request
to its neighbor devices through its NTDP-enable ports. The topology collection
response packet contains the information about the local device and the NDP
information about all the neighbor devices.
The neighbor devices perform the same operation until the NTDP topology
collection request is propagated to all the devices within the specified hops.
2-5
Chapter 2 Cluster