# Interface Discovery and scheduling in OpManager

An interface is a component that connect a network device to the network, and helps in the communication and transfer of data between these devices over a private or public network. Monitoring the interfaces of network devices is crucial to understanding the behavior of the network in terms of flow of traffic, or bandwidth utilization.

OpManager provides comprehensive network interface monitoring with advanced bandwidth and flow analysis to monitor the interfaces in your network. With support for close to 300 different types of interfaces straight out-of-the-box, including Ethernet interfaces, PPP, Software Loopback, fibre channel, virtual interfaces, and many more. The SNMP protocol and the corresponding SNMP monitors are used to keep an eye on various interface metrics like traffic, bandwidth, utilization, number of transferred packets and their size, the errors and discards of the interface, etc.

**Prerequisites for interface discovery:**

- The parent device must be active and running.
- SNMP service must be enabled on the device.
- The SNMP credentials to the device must be configured correctly in OpManager.
- The SNMP port configured for the SNMP agent must be the same as the port configured for OpManager (**by default, 161**).
- The IP of OpManager server must not be blocked on the SNMP agent.

## Methods of Interface Discovery

Interfaces can be discovered in OpManager using three main methods. They include:

1. [Discovering the interfaces of each device individually through the device snapshot page](https://manageengine.com/network-monitoring/how-to/interface-addition-howto.html#device-snapshot-page)
2. [Discovering interfaces in bulk through interface discovery](https://manageengine.com/network-monitoring/how-to/interface-addition-howto.html#bulk-discovery)
3. [Automatic discovery of interfaces during device discovery in OpManager](https://manageengine.com/network-monitoring/how-to/interface-addition-howto.html#add-device)

## Scheduling the discovery of interfaces

From OpManager v127241 onwards, it is possible to schedule the discovery of interfaces for a later time. Additionally, you can also configure the schedule to repeat the interface discovery process every once in a while. The criteria and conditions for the interface discovery, along with the configurations for its scheduling, are saved to a profile called the **Interface Discovery Profile**. This profile can be scheduled to run as many times as required, according to your requirement, to keep your inventory updated with all the interfaces associated with the devices in your network.

**Steps to schedule the discovery of interfaces:**

- Navigate to **Settings > Discovery > Interface Discovery**.
- Click on **New Discovery**.
- Add a profile name and description for the **Interface Discovery Profile**.
- Configure the conditions and criteria of the device(s) for which you want to run the interface discovery.
- Click on **Schedule**.

![Interface discovery and scheduling in OpManager: Interface Discovery Schedule](https://www.manageengine.com/network-monitoring/help/images/scheduled-interface-discovery-new-1.PNG)

- The Interface Discovery Profile will be successfully added, the configured criteria and conditions will be saved to the profile, and you will be taken to a page where you can configure the **Discovery Schedule** for your discovery profile.

![Interface discovery and scheduling in OpManager: Interface Discovery Profile Saved](https://www.manageengine.com/network-monitoring/help/images/scheduled-interface-discovery-new-2.PNG)

- Choose how frequently you want to run the discovery schedule. Options include **Once**, **Daily**, **Weekly**, **Monthly**, and **Yearly**.

![Interface discovery and scheduling in OpManager: Interface Discovery Schedule Frequency](https://www.manageengine.com/network-monitoring/help/images/scheduled-interface-discovery-new-3.PNG)

- Add the corresponding options for the frequency you have selected.
- Select whether you want the **Re-Discovery Rule** to be executed if an interface is newly added/deleted.
- Click on **Save**.
- The configured discovery schedule will be saved to the Interface Discovery Profile.

![Interface discovery and scheduling in OpManager: Interface Discovery Scheduled Successfully](https://www.manageengine.com/network-monitoring/help/images/scheduled-interface-discovery-new-4.PNG)

## Interface Re-Discovery Rule

There are instances when interfaces are added to the device after they have been discovered in OpManager (ex. configuring a new VLAN interface, creating a new fibre channel interface, etc.). Similarly, some interfaces could be removed from the device after their addition to OpManager (ex. deleting an Ethernet interface from a Windows device, or disabling a PPP interface on a router, etc.). The interface re-discovery rule is a set of conditions and configurations that allow you to choose what OpManager must do when it encounters such new interfaces on a device, or if it identifies that some interfaces have been deleted from the device. This rule is executed every time the interface discovery profile is executed based on the configured schedule. During this scheduled discovery, OpManager executes the rediscovery rule and identifies the interfaces that match the given criteria, and can either add them to the inventory or remove/unmanage them according to the options set by the user.

While configuring the re-discovery rule, you can choose to perform two operations:

- **If a new interface is found**, you can choose to either add the interface and start monitoring, or you can ignore the new interfaces.
- **If an interface has been** (previously) **deleted**, you can choose to delete, or unmanage the interface from OpManager.

![Interface discovery and scheduling in OpManager: Interface Discovery Rule](https://www.manageengine.com/network-monitoring/help/images/scheduled-interface-discovery-new-5.png)