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Using the Device Layer View

The device layer view at Devices > Views displays the data collected from monitored devices you have previously discovered using the device discovery process. The Enterprise Agents that monitor these devices poll at 5-minute intervals to collect data to populate the view. In addition to a timeline view, the device layer view shows three tabs: Topology, Interface Table, and Device Table.

Timeline

The Timeline shows data according the the filters and metrics you set.

  • Add a filter: Select one or more filters for the data to be displayed in the timeline:
    • Agent
    • Device
      • Device
      • Device Type
    • Interface
      • Interface
      • Interface Type
  • Metric: Select the metric to be used in the timeline:
    • Network
      • Throughput: The aggregate throughput of all selected Interfaces on all selected devices.
      • Discards: The number of discarded packets of all selected Interfaces on all selected devices. Input packet discards typically indicate device resource constraints. Output packet discards typically indicate network connection saturation.
      • Errors: The number of errors of all selected Interfaces on all selected devices. Errors typically indicate faulty cables, switch ports or interfaces.
    • System
      • CPU
      • Memory

Topology

The Topology tab builds a network diagram of all discovered devices and other devices, along with their layer-2 links. Enterprise Agents poll devices via SNMP, querying each device's management information base (MIB) for Link Layer Discovery Protocol (LLDP) and for Cisco Discovery Protocol (CDP) data to obtain the topology information.

{% hint style="warning" %} The Topology view is rendered client side, and limited to 250 devices to ensure it is rendered before the browser becomes unresponsive. {% endhint %}

  1. Standard visualization tools to locate devices and connections that match specified criteria.
  2. Discovered Device: Each device is represented by an icon according to the device type. You can change the device type in Devices > Device Settings. Hover over a device for additional information about it.
  3. Undiscovered Device: Devices that were not discovered by device discovery, but are reported as neighbors by discovered devices are shown as unknown devices.
  4. Non-Reporting Device: Devices that were discovered, but provided no information about the links to other discovered devices, are not connected to any other device in the Topology view.
  5. Link: Devices are interconnected with Layer 2 links. Hover over a link for additional information about the link.
  6. Edit Topology Layout: If the discovered topology does not reflect your network, click Edit Topology Layout to change the topology view layout. Change the layout by placing discovered devices into different tiers.

Interface Table

The interface table displays per-interface metrics, identifying devices and interfaces that contribute most to the metrics. The interface table displays interface status for every monitored interface of the selected device. Speed indicates the reported speed of an interface. If an interface is a Layer-3 interface and has an IP address, the IP address is shown.

Device Table

The Device Table tab displays device status, device description information, the number of active interfaces, and aggregated interface metrics.

Troubleshooting

A network device is discovered and can be selected in the Timeline view, but is not seen in Topology view.

Ensure the network device has either or both LLDP and CDP configured and active, and ensure either or both LLDP and CDP MIBs are exposed through the SNMP protocol.

A new device was discovered, but timeline shows no interface metrics

Ensure you have enabled one or more interfaces in the Monitored Interfaces selector of the Device Settings page. Please note that first interface metrics are available 15 minutes after the initial device discovery.