arp-throttle

Syntax

Hierarchy Level

Description

Define the time duration (in seconds) for Address Resolution Protocol (ARP) request throttling to remain active when it is triggered.

When ARP throttling is triggered, it is active for a given logical interface. For the configured duration of time, the ARP throttling remains active, and the traffic entering into the specific interface does not trigger ARP nexthop resolution requests, which are being sent to the Routing Engine from the specific SPU.

When you configure a longer time duration, the ARP throttling can protect the Routing Engine by preventing too many ARP requests being triggered by incoming traffic.

For example, if there is a large amount of traffic destined to a directly connected, unresolved IP address, chances of getting frequent ARP requests is very high, which eventually results into a high CPU load on the Routing Engine. By setting a longer time interval of the ARP throttle, the Routing Engine is protected from numerous ARP requests.

For example, when you configure the set forwarding-options nexthop arp-throttle 15 option, and the interface state changes to throttle state, the nexthop requests triggered by incoming traffic into this interface, will not be sent. After 15 seconds, interface changes back from throttle to normal state. Then the nexthop requests triggered by the incoming traffic into this interface are sent to the Routing Engine again.

Options

seconds—Time interval (in seconds) for Address Resolution Protocol (ARP) request throttling to remain active when it is triggered.

• Range: 10 through 100 seconds

• Default: 10 seconds

Required Privilege Level

security—To view this statement in the configuration.

security-control—To add this statement to the configuration.

Release Information

Statement introduced in Junos OS Release 12.3X48-D65, Junos OS Release 15.1X49-D60, and Junos OS Release 15.1X49-D130.