Brocade BigIron RX Series Configuration Guide - Manual (Page 269)

BigIron RX Series Configuration Guide 191
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Configuring ARP parameters
7
BigIron RX(config)# arp-port-rate-limit 100
This command configures the device to accept up to 100 ARP packets each second. If the device
receives more than 100 ARP packets during a one-second interval, the device drops the additional
ARP packets during the remainder of that one-second interval.
Syntax: [no] arp-port- rate-limit <num>
The <num> parameter specifies the number of ARP packets and can be from 0 – 30,000. If you
specify 0, the device will not accept any ARP packets.
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
• 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).
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.