# NSRP Monitor - Track IP

Path monitoring checks the layer 2 and layer 3 network connections between a interface and the interface of another device. Path monitoring is a useful tool for devices within a redundant group to determine whether the network connectivity of the device is acceptable.

Layer 2 path monitoring functions by checking that the physical ports are active and connected to other network devices. Layer 3 path monitoring, or IP tracking, functions by sending ping or ARP requests to up to 16 specified IP addresses at user-determined intervals and then monitoring if the targets respond.

When tracking IP addresses, you can send ping or ARP requests from either a Manage IP address for a physical, redundant, or sub-interface or from the IP address of the physical interface, redundant interface, or sub-interface itself. (If you do not specify a Manage IP address, the path monitoring service uses the interface IP address.) Juniper Networks recommends that you define a Manage IP address for IP tracking. Note that you cannot use a VSI for IP tracking because that address can shift its bindings among multiple devices.

## Track IP Table

The Track IP table lists the following information about tracked IP addresses for the device and for each VSD:

IP Address: Identifies the tracked IP address.

Interval (sec): Indicates the interval of time between ping or ARP requests.

Threshold: Indicates the number of consecutive failures to elicit a ping or ARP response from a specific IP address required to be considered a failed attempt.

Interface: Identifies the interface from which the device sends the ping or ARP request.

Weight: Indicates the weight of the tracked IP address.

Method: Indicates the method by which the device polls a remote device: Ping or ARP.

Configure: Click Edit to modify the existing Track IP entry, or click Remove to delete it from the system.

### To Configure a Tracked IP Address

Click New. For more information on configuring a track IP, see Track IP Configuration.

The New button appears only after you configure an NSRP cluster.

### To Enable IP Tracking for the Device or VSD

Click Edit for the device or VSD Failover Threshold. For more information on enabling track IP on the device or VSD, see Enabling Track IP.