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Using CDP to detect network connectivity

Using CDP to detect network connectivity consists of reviewing deployment considerations, enabling it on data ports, viewing neighbor devices, and adjusting CDP configuration values as needed. CDP is enabled by default on cluster ports.

Before you begin

CDP must also be enabled on any switches and routers before information about neighbor devices can be displayed.

About this task

CDP is also used by the cluster switch health monitor to automatically discover your cluster and management network switches.

  • Considerations for using CDP
    By default, CDP-compliant devices send CDPv2 advertisements. CDP-compliant devices send CDPv1 advertisements only when they receive CDPv1 advertisements. ONTAP supports only CDPv1. Therefore, when an ONTAP node sends CDPv1 advertisements, CDP-compliant neighboring devices send back CDPv1 advertisements.
  • Enabling or disabling CDP
    To discover and send advertisements to CDP-compliant neighboring devices, CDP must be enabled on each node of the cluster. By default, CDP is enabled on all cluster ports of a node and disabled on all non-cluster ports of a node.
  • Viewing CDP neighbor information
    You can view information about the neighboring devices that are connected to each port of the nodes of your cluster, provided that the port is connected to a CDP-compliant device. You can use the cdpd show-neighbors command to view neighbor information. The network device-discovery show command can also be used to display information about neighboring devices.
  • Configuring the hold time for CDP messages
    Hold time is the period of time for which CDP advertisements are stored in cache in neighboring CDP-compliant devices. Hold time is advertised in each CDPv1 packet and is updated whenever a CDPv1 packet is received by a node.
  • Setting the interval for sending CDP advertisements
    CDP advertisements are sent to CDP neighbors at periodic intervals. You can increase or decrease the interval for sending CDP advertisements depending on network traffic and changes in the network topology.
  • Viewing or clearing CDP statistics
    You can view the CDP statistics for the cluster and non-cluster ports on each node to detect potential network connectivity issues. CDP statistics are cumulative from the time they were last cleared.