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Figure 52. ARP Learning via ARP Request
Beginning with the Dell Networking OS version 8.3.1.0, when you enable ARP learning via gratuitous ARP, the system installs a
new ARP entry, or updates an existing entry for all received ARP requests.
Figure 53. ARP Learning via ARP Request with ARP Learning via Gratuitous ARP Enabled
Whether you enable or disable ARP learning via gratuitous ARP, the system does not look up the target IP. It only updates the
ARP entry for the Layer 3 interface with the source IP of the request.
Configuring ARP Retries
In the Dell Networking OS versions prior to 8.3.1.0, the number of ARP retries is set to five and is not configurable. After five
retries, the system backs off for 20 seconds before it sends a new request. Beginning with the Dell Networking OS version
8.3.1.0, the number of ARP retries is configurable.
The default backoff interval remains at 20 seconds. On the switch using the Dell Networking OS version 8.3.8.0 and later,
the time between ARP re-send is configurable. This timer is an exponential backoff timer. Over the specified period, the time
between ARP requests increases. This reduces the potential for the system to slow down while waiting for a multitude of ARP
responses.
To set and display ARP retries, use the following commands.
● Set the number of ARP retries.
CONFIGURATION mode
arp retries number
The default is 5.
The range is from 1 to 20.
● Set the exponential timer for resending unresolved ARPs.
CONFIGURATION mode
arp backoff-time
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IPv4 Routing