HP 5300XL, 5304XL, 5348XL Note on Path Cost

802.1w Rapid Spanning Tree Protocol (RSTP) 802.1d Spanning Tree Protocol (STP)

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>	forc <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 implements 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 Path Cost
10 Mbps	100	2 000 000
100 Mbps	10	200 000
1 Gbps	5	20 000
10 Gbps	?	2000

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, at least for 10 Mbps and 100 Mbps ports. In LANs where there is a mix of devices running 802.1d STP and RSTP, you should reconfigure the devices so the path costs match for ports with the same network speeds.

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