Dell BigIron RX Series, Configuration Manual

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390 BigIron RX Series Configuration Guide
53-1002253-01
Configuring RSTP parameters
13
BigIron RX(config)# fast port-span
BigIron RX(config)# write memory
Excluding specific ports from fast port span
You can exclude individual ports from Fast Port Span while leaving Fast Port Span enabled globally.
To do so, use the following method.
Using the CLI
To exclude a port from Fast Port Span, enter commands such as the following.
BigIron RX(config)# fast port-span exclude ethernet 1/1
BigIron RX(config)# write memory
To exclude a set of ports from Fast Port Span, enter commands such as the following.
BigIron RX(config)# fast port-span exclude ethernet 1/1 ethernet 2/1 ethernet 3/2
BigIron RX(config)# write memory
To exclude a contiguous (unbroken) range of ports from Fast Span, enter commands such as the
following.
BigIron RX(config)# fast port-span exclude ethernet 1/1 to 1/24
BigIron RX(config)# write memory
Syntax: [no] fast port-span [exclude ethernet <portnum> [ethernet <portnum> … | to <portnum> ]]
To re-enable Fast Port Span on a port, enter a command such as the following.
BigIron RX(config)# no fast port-span exclude ethernet 1/1
BigIron RX(config)# write memory
This command re-enables Fast Port Span on port 1/1 only and does not re-enable Fast Port Span
on other excluded ports. You also can re-enable Fast Port Span on a list or range of ports using the
syntax shown above this example.
To re-enable Fast Port Span on all excluded ports, disable and then re-enable Fast Port Span by
entering the following commands.
BigIron RX(config)# no fast port-span
BigIron RX(config)# fast port-span
BigIron RX(config)# write memory
Disabling and then re-enabling Fast Port Span clears the exclude settings and thus enables Fast
Port Span on all eligible ports. To make sure Fast Port Span remains enabled on the ports
following a system reset, save the configuration changes to the startup-config file after you
re-enable Fast Port Span. Otherwise, when the system resets, those ports will again be excluded
from Fast Port Span.
Fast uplink span
The Fast Port Span feature described in the previous section enhances STP performance for end
stations. The Fast Uplink feature enhances STP performance for wiring closet switches with
redundant uplinks. Using the default value for the standard STP forward delay, convergence
following a transition from an active link to a redundant link can take 30 seconds (15 seconds for
listening and an additional 15 seconds for learning).