Dell S4820T User Manual

Figure 48. 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 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, Dell Networking OS backs off for 20 seconds before it sends a new
request. Beginning with 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 device, the time between ARP resend is
configurable. This timer is an exponential backoff timer. Over the specified period, the time between ARP
requests increases. This time increase 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
The default is 30.
The range is from 1 to 3600.
• Display all ARP entries learned via gratuitous ARP.
EXEC Privilege mode
show arp retries
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IPv4 Routing

Dell S4820T Specifications

General

Brand	Dell
Model	S4820T
Category	Switch
Language	English