BigIron RX Series Configuration Guide 18153-1001810-01Configuring ARP parameters 7Applying a rate limit to ARP packets on an interfaceTo prevent the CPU from becoming flooded by ARP packets in a busy network, you can restrict thenumber of ARP packets an interface will accept each second. When ARP rate limit is configured onan interface, the interface will accept up to the maximum number of packets you specify, but dropsadditional ARP packets received during the one-second interval. When a new one-second intervalstarts, the counter restarts at zero, so the interface again accepts up to the maximum number ofARP packets you specified, but drops additional packets received within the interval. This feature isdisabled by default.Configuration notes• 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 . Enter 0–30,000.• If the value of is entered as 0, the interface will stop processing ARP packetsimmediately.• You can go to interface trunk mode to configure the ARP port rate limit. When configured overtrunk interface (i.e. on the lead port) the same limit will be configured on each and every portin the trunk.• ARP rate limiting is only supported on physical interfaces (virtual interfaces (ve) are notsupported).Setting the rate limit to ARP packets on an interfaceYou can limit the number of ARP packets the device will accept each second by entering thearp-port-rate-limit command. However, if you want to apply a limit on the rate that ARP packets flowon an interface of a Layer 3 Switch, enter a command such as the following.BigIron RX(config)#interface ethernet 1/4BigIron RX(config-vif-10)#arp-port-rate-limit 2000Syntax: [no] arp-port-rate-limit There is no default value for . Enter 0–30,000.Displaying the rate limit for ARP packetsTo determine how many ARP packets were dropped by an interface due to the configured rate limitfor ARP packets, enter a command such as the following.LP-1#show ip traffic arpARP Statistics1400 total recv, 1400 req recv, 0 req sent0 pending drop, 0 invalid source, 0 invalid destARP Rate Limiting StatisticsInterface Received Processed Dropped(Rate-limted)ethernet1/1 184200 700 183500ethernet1/2 0 0 0ethernet1/3 0 0 0ethernet1/4 184200 700 183500
