---
title: NDM Terms and Concepts
description: NDM Glossary
breadcrumbs: Docs > Network Monitoring > Network Device Monitoring > NDM Terms and Concepts
---

# NDM Terms and Concepts

## Overview{% #overview %}

Network Device Monitoring (NDM) helps you gain insights into the health and performance of your on-prem routers, switches, and firewalls. For additional definitions and descriptions of important NDM terms such as *layer 2* and *layer 3*, see the main [Glossary](https://docs.datadoghq.com/glossary/?product=network-device-monitoring).

## Terminology{% #terminology %}

{% dl %}

{% dt %}
Simple network management protocol (SNMP)
{% /dt %}

{% dd %}
A network protocol that is used to collect information about bare metal networking gear.
{% /dd %}

{% dt %}
Link Layer Discovery Protocol (LLDP)
{% /dt %}

{% dd %}
A protocol used by devices to advertise identity and capabilities to neighboring devices. NDM uses LLDP to map topology.
{% /dd %}

{% dt %}
Managed information base (MIB)
{% /dt %}

{% dd %}
A database or list of all the possible OIDs and their definitions that are related to the MIB. For example, the `IF-MIB` (interface MIB) contains all the OIDs for descriptive information about a device's interface.
{% /dd %}

{% dt %}
Object identifier (OID)
{% /dt %}

{% dd %}
A unique ID or address on a device that when polled returns the response code of that value. For example, OIDs are CPU or device fan speed.
{% /dd %}

{% dt %}
System object identifier (sysOID)
{% /dt %}

{% dd %}
A specific address that defines the device type. All devices have a unique ID that defines it. For example, the Meraki base sysOID is `1.3.6.1.4.1.29671`.
{% /dd %}

{% dt %}
Managed information base (MIB)
{% /dt %}

{% dd %}
A database or list of all the possible OIDs and their definitions that are related to the MIB. For example, the `IF-MIB` (interface MIB) contains all the OIDs for descriptive information about a device's interface.
{% /dd %}

{% dt %}
[Profiles](https://docs.datadoghq.com/network_monitoring/devices/profiles)
{% /dt %}

{% dd %}
A profile is a collection of OIDs associated with a device. Profiles allow NDM to reuse metric definitions across several device types or instances.
{% /dd %}

{% dt %}
Software-defined wide area network (SD-WAN)
{% /dt %}

{% dd %}
A wide area network (WAN) that uses software-defined networking (SDN). SD-WAN is often used to interconnect remote offices and data centers across different transports (MPLS, broadband, 5G, and so on).
{% /dd %}

{% dt %}
[Device namespaces](https://docs.datadoghq.com/network_monitoring/devices/snmp_traps/?tab=yaml#device-namespaces)
{% /dt %}

{% dd %}
Namespace of the device. Namespaces can be used as tags to differentiate between multiple network devices that may share the same private IP.
{% /dd %}

{% dt %}
[Ping](https://docs.datadoghq.com/network_monitoring/devices/ping)
{% /dt %}

{% dd %}
A network tool that measures how long it takes for a signal to travel from one device to another over a network and back again.
{% /dd %}

{% /dl %}

## Further Reading{% #further-reading %}

- [SNMP Monitoring Overview](https://www.datadoghq.com/knowledge-center/network-monitoring/snmp-monitoring/)