KB.15.15

Figure 25 Sample RPVST+ network

Working with the default RPVST+ configuration

In the factory default configuration, spanning tree operation is disabled. Configuring the spanning

tree mode as RPVST+ on a switch and then enabling spanning tree automatically creates a spanning

tree instance for each VLAN on the switch. Configuration with default settings is automatic, and

in many cases does not require any adjustments. This includes operation with spanning tree regions

in your network running STP, MSTP, or RSTP. Also, the switch retains its currently configured

spanning tree parameter settings when spanning tree is disabled. Thus, if you disable, then later

re-enable spanning tree, the parameter settings will be the same as before spanning tree was

disabled.

CAUTION: The switch automatically senses port identity and type, and automatically defines

spanning tree parameters for each type, as well as parameters that apply across the switch.

Although these parameters can be adjusted, HP strongly recommends leaving these settings in their

default configurations unless the proposed changes have been supplied by an experienced network

administrator who has a strong understanding of RPVST+ operation.

Operating notes

Recommended application RPVST+ is ideal in networks having less than 100 VLANs. In

networks having 100 or more VLANs, MSTP is the

recommended spanning tree choice due to the increased load

on the switch CPU.

VLAN membership A port will be part of a given VLAN spanning tree only if the port is a

member of that VLAN.

RPVST+ interoperates with RSTP and

MSTP on VLAN 1

Because a switch running RPVST+ transmits IEEE spanning

tree BPDUs, it can interoperate with IEEE RSTP and MSTP

spanning tree regions, and opens or blocks links from these

regions as needed to maintain a loop-free topology with

one physical path between regions.

NOTE: RPVST+ interoperates with RSTP and MSTP only

on VLAN 1.

166 Rapid per-VLAN spanning tree (RPVST+) operation