Spanning-Tree Operation
Configuring Rapid Reconfiguration Spanning Tree (RSTP)
Syntax: Abbreviations:
spanning-tree [ethernet] < port-list >
span < port-list >
path-cost < 1 - 200000000 >
path <1 - 200000000>
point-to-point-mac < force-true | force-false | auto >
force < force-t | force-f | auto >
priority < 0 - 15 >
pri <0 - 15>
[no] spanning-tree [ethernet] < port-list >
[no] span < port-list >
edge-port
edge
mcheck
mch
Defaults: see the table on the previous page.
Note on Path Cost RSTP and MSTP implement a greater range of path costs and new default path
cost values to account for higher network speeds. These values are different
than the values defined by 802.1D STP as shown below.
Port Type 802.1D STP Path Cost RSTP and MSTP Path Cost
10 Mbps 100 2 000 000
100 Mbps 10 200 000
1 Gbps 5 20 000
Because the maximum value for the path cost allowed by 802.1D STP is 65535,
devices running that version of spanning tree cannot be configured to match
the values defined by RSTP and MSTP, at least for 10 Mbps and 100 Mbps
ports. In LANs where there is a mix of devices running 802.1D STP, RSTP, and/
or MSTP, you should reconfigure the devices so the path costs match for ports
with the same network speeds.
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