Brocade FastIron Ethernet Switch Platform and Layer 2 Switching Configuration Guide - Manual (Page 22)

Changing the MAC age time and disabling MAC address learning
To change the MAC address age timer, enter a command such as the following.
device(config)#mac-age-time 60
Syntax: [no] mac-age-time secs
secs specifies the number of seconds. Possible values differ depending on the version of software
running on your device, as follows:
• On Brocade FCX Series devices, you can configure the MAC address age timer to 0 or a value from
10-1000 (seconds). If you set the MAC age time to 0, aging is disabled.
• On FastIron X Series devices, you can configure 0 or a value from 10 - 86,400 (seconds), in 10-
second intervals. If you set the MAC age time to 0, aging is disabled.
• On ICX Series devices, you can configure the MAC address age timer to 0 or a value from 10-570
(seconds). If you set the MAC age time to 0, aging is disabled.
• If the total MAC addresses in the system is more than 16000, Brocade recommends a MAC age
timer greater than 60 seconds. If the total MAC addresses in the system is more than 64000,
Brocade recommends a MAC age timer greater than 120 seconds.
On ICX 6650, you can configure a value from 0 or a value from 10-600. The defaut is 300. If you set
the MAC age time to 0, aging is disabled.
NOTE
Usually, the actual MAC age time is from one to two times the configured value. For example, if you
set the MAC age timer to 60 seconds, learned MAC entries age out after remaining unused for
between 60 - 120 seconds. However, if all of the following conditions are met, then the MAC entries
age out after a longer than expected duration:
• The MAC age timer is greater than 630 seconds.
• The number of MAC entries is over 6000.
• All MAC entries are learned from the same packet processor.
• All MAC entries age out at the same time.
Disabling the automatic learning of MAC addresses
By default, when a packet with an unknown Source MAC address is received on a port, the Brocade
device learns this MAC address on the port.
You can prevent a physical port from learning MAC addresses by entering the following command.
device(config)#interface ethernet 3/1
device(config-if-e1000-3/1)#mac-learn-disable
Syntax: [no] mac-learn disable
Use the no form of the command to allow a physical port to learn MAC addresses.
Changing the MAC age time and disabling MAC address learning
22 FastIron Ethernet Switch Platform and Layer 2 Switching Configuration Guide
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