HP JD320B User Manual

• The management switch adds or deletes a member switch and modifies cluster management
configuration according to the candidate switch information collected through NTDP.
Introduction to NDP
NDP discovers the information about directly connected neighbors, including the device name, software
version, and connecting port of the adjacent devices. NDP works in the following ways:
• A device running NDP periodically sends NDP packets to its neighbors. An NDP packet carries
NDP information (including the device name, software version, and connecting port, and so on)
and the holdtime, which is how long the receiving devices will keep the NDP information. At the
same time, the device also receives (but does not forward) NDP packets from its neighbors.
• A device running NDP stores and maintains an NDP table. The device creates an entry in the NDP
table for each neighbor. If a new neighbor is found, meaning the device receives an NDP packet
sent by the neighbor for the first time, the device adds an entry in the NDP table. If the NDP
information carried in the NDP packet is different from the stored information, the corresponding
entry and holdtime in the NDP table are updated; otherwise, only the holdtime of the entry is
updated. If an entry’s holdtime expires (in other words, no NDP information from the neighbor is
received to restart the hold time before it ages out), the entry is removed from the NDP table.
NDP runs on the data link layer, and supports different network layer protocols.
Introduction to NTDP
NTDP provides information required for cluster management; it collects topology information about the
devices within the specified hop count. Based on the neighbor information stored in the neighbor table
maintained by NDP, NTDP on the management switch advertises NTDP topology-collection requests to
collect the NDP information of all the devices in a specific network range as well as the connection
information of all its neighbors. The information collected will be used by the management switch or the
network management software to implement required functions.
When a member switch detects a change on its neighbors through its NDP table, it informs the
management switch through handshake packets. Then the management switch triggers its NTDP to
collect specific topology information, so that its NTDP can discover topology changes promptly.
The management switch collects topology information periodically. You can also administratively launch
a topology information collection. Topology information collection includes the following process:
• The management switch periodically sends NTDP topology-collection request from the
NTDP-enabled ports.
• Upon receiving the request, the device sends NTDP topology-collection response to the
management switch, copies this response packet on the NTDP-enabled port and sends it to the
adjacent device. Topology-collection response includes the basic information of the NDP-enabled
device and NDP information of all adjacent devices.
• The adjacent device performs the same operation until the NTDP topology-collection request is sent
to all the devices within specified hops.
When the NTDP topology-collection request is advertised in the network, large numbers of network
devices receive the NTDP topology-collection request and send NTDP topology-collection response at the
same time, which may cause congestion and the management switch busyness. To avoid such case, use
the following methods to control the speed of the NTDP topology-collection request advertisement:
• Upon receiving an NTDP topology-collection request, each device does not forward it, instead, it
waits for a period of time and then forwards the NTDP topology-collection request on the first
NTDP-enabled port.
• On the same device, except the first port, each NTDP-enabled port waits for a period of time and
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HP JD320B Specifications

General

Brand	HP
Model	JD320B
Category	Switch
Language	English