Dell FCX624-E Laptop User Manual


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PowerConnect B-Series FCX Configuration Guide 307
53-1002266-01
MAC learning rate control
9
You can also enable and disable spanning tree on a port-based VLAN and on an individual port
basis, and enable advanced STP features. Refer to Chapter 8, “Configuring Spanning Tree Protocol
(STP) Related Features”.
Modifying STP bridge and port parameters
You can modify the following STP Parameters:
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 210.
MAC learning rate control
You can set a rate limit to control CPU address updating. The range for this rate limit is 200 -
50,000 per second. The MAC learning rate limit applies to each packet processor, which means
that for a system with two packet processors, each processor can send address messages to the
CPU at the established rate limit.
Syntax: [no] cpu-limit addr-msgs <msgsRateLimit>
NOTE
Actual rates in hardware may have a variance of +200 or -100.
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 FCX devices, learned MAC address entries do not age out until they
are unused for 300 – 600 seconds. If necessary, you can change the MAC address age timer
to 0 or a value from 60 – 600 (seconds), in 60-second intervals. For example, you can specify
60 or 120, but not 100. 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.