Quick Reference Guide

176 PowerConnect B-Series TI24X Configuration Guide
53-1002269-02
Changing the MAC age time and disabling MAC address learning
7
• Bridge parameters – forward delay, maximum age, hello time, and priority
• Port parameters – priority and path cost
For configuration details, refer to “Changing STP bridge and port parameters” on page 96.
Changing the MAC age time and disabling MAC address learning
To change the MAC address age timer, enter a command such as the following.
PowerConnect(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 PowerConnect B-Series TI24Xdevices, you can configure 0 or a value from 10 – 86,400
(seconds), in 1-second intervals. If you set the MAC age time to 0, aging is disabled.
NOTES: 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 device
learns this MAC address on the port.
You can prevent a physical port from learning MAC addresses by entering the following command.
PowerConnect(config)#interface ethernet 1
PowerConnect(config-if-e10000-1)#mac-learn-disable
Syntax: [no] mac-learn disable
Use the no form of the command to allow a physical port to learn MAC addresses.
Configuration notes and feature limitations
• This command is not available on virtual routing interfaces. Also, if this command is configured
on the primary port of a trunk, MAC address learning will be disabled on all the ports in the
trunk.
• Entering the mac-learn-disable command on tagged ports disables MAC learning for that port
in all VLANs to which that port is a member. For example, if tagged port 1 is a member of VLAN
10, 20, and 30 and you issue the mac-learn-disable command on port 1, port 1 will not learn
MAC addresses, even if it is a member of VLAN 10, 20, and 30.