Discovering Devices
ThousandEyes’ Device Layer auto-discovers network infrastructure and collects diagnostic information using LLDP/CDP (Link Layer Discovery Protocol/Cisco Discovery Protocol) and SNMP (Simple Network Management Protocol) device polling. It also maps your devices in a single system topology, so you can quickly locate failure points. You can customize this path visualization of your network to help match your own understanding of the network.
Why We Recommend Device Discovery
The Device Layer uses ThousandEyes Enterprise Agents to poll devices like switches, routers and firewalls on your network so it can determine link states, throughput, errors, discards by interface, as well as other metrics. You can then track, report and alert on the performance of a device, subnet or your entire network, and compare new trends across time and locations to detect bottlenecks.
SNMP device discovery is not essential to configuring your network flows in Traffic Insights. However, in order to better correlate between ThousandEyes data views for Network & App Synthetics and the data views for Traffic Insights, you must discover the devices that you designate as your traffic monitors from an Enterprise Agent on your network. That is, if the device shows up as a node in the path visualization of a test and there are network flows going from it to an Enterprise Agent with Traffic Insights enabled, device discovery means you can simply click on the device to take you directly into a filtered view in Traffic Insights for a deeper dive into that device's current metrics.
SNMP device discovery is also necessary to unlock device identification features such as the device name (like ISR4451cEdge) and interface type (like GigabitEthernet0/0/2) that are sending flow data; otherwise, only the device IP address is shown in the Traffic Insights views, which can make device identification difficult.
For this step, you need to know which devices you plan to configure as traffic monitors. If you are unsure, you can configure your traffic monitors before device discovery.
Run SNMP Device Discovery
Find instructions for device discovery at Device Layer. Note, the Enterprise Agent you use to discover the network devices does not have to be one you designated as a forwarder.
Once you have discovered your devices, you can optionally monitor your devices with SNMP for regular status updates; click the check box next to the device you wish to monitor, then the Monitor button. If you want to only monitor certain interfaces, you can use the Edit Device dropdown to select the interfaces. This feature can help isolate noise from interfaces that don't need to be monitored like user switch ports versus critical uplink ports.
Once flows are being sent to the forwarders on your discovered devices (typically after traffic monitor configuration), you can view them in Traffic Insights > Settings > Forwarders.
(Optional) Enable ACLs on the Traffic Monitor
In addition to standard device discovery, you may need to enable Access Control Lists (ACLs) for the network device that is serving as the traffic monitor for Traffic Insights. You need to allow the ThousandEyes Enterprise Agent to discover this network device and to receive flow data.
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