Applying A Rate Limit To Arp Packets On An Interface - Dell PowerConnect B-RX Configuration Manual

Applying a rate limit to ARP packets on an interface

To prevent the CPU from becoming flooded by ARP packets in a busy network, you can restrict the
number of ARP packets an interface will accept each second. When ARP rate limit is configured on
an interface, the interface will accept up to the maximum number of packets you specify, but drops
additional ARP packets received during the one-second interval. When a new one-second interval
starts, the counter restarts at zero, so the interface again accepts up to the maximum number of
ARP packets you specified, but drops additional packets received within the interval. This feature is
disabled by default.
Configuration notes
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Setting the rate limit to ARP packets on an interface
You can limit the number of ARP packets the device will accept each second by entering the
arp-port-rate-limit command. However, if you want to apply a limit on the rate that ARP packets flow
on an interface of a Layer 3 Switch, enter a command such as the following.
BigIron RX(config)#interface ethernet 1/4
BigIron RX(config-vif-10)#arp-port-rate-limit 2000
Syntax: [no] arp-port-rate-limit <rate>
There is no default value for <rate>. Enter 0–30,000.
Displaying the rate limit for ARP packets
To determine how many ARP packets were dropped by an interface due to the configured rate limit
for ARP packets, enter a command such as the following.
LP-1#show ip traffic arp
ARP Statistics
1400 total recv, 1400 req recv, 0 req sent
0 pending drop, 0 invalid source, 0 invalid dest
ARP Rate Limiting Statistics
Interface
ethernet1/1
ethernet1/2
ethernet1/3
ethernet1/4
BigIron RX Series Configuration Guide
53-1001810-01
When configuring ARP rate limiting globally, interfcae level ARP rate-limiting gets removed.
The interface level configuration overrides the global configuration for a specific port.
The command is supported on Layer 3 Switches only.
There is no default value for <rate>. Enter 0–30,000.
If the value of <rate> is entered as 0, the interface will stop processing ARP packets
immediately.
You can go to interface trunk mode to configure the ARP port rate limit. When configured over
trunk interface (i.e. on the lead port) the same limit will be configured on each and every port
in the trunk.
ARP rate limiting is only supported on physical interfaces (virtual interfaces (ve) are not
supported).
Received
184200
0
0
184200
Configuring ARP parameters
Processed Dropped(Rate-limted)
700
0
0
700
183500
0
0
183500
7
181