ProLiant BL p-Class GbE2 Interconnect Switch Application Guide

Spanning Tree Protocol 60
Figure 9 Two VLANs on one instance of Spanning Tree Protocol
In the following figure, VLAN 1 and VLAN 2 belong to different Spanning Tree Groups. The two instances of
spanning tree separate the topology without forming a loop, so that both VLANs can forward packets between
the switches without losing connectivity.
Figure 10 Two VLANs on separate instances of Spanning Tree Protocol
VLAN participation in Spanning Tree Groups
The following table shows which switch ports participate in each Spanning Tree Group. By default, server ports
(ports 1-16) do not participate in Spanning Tree, even though they are members of their respective VLANs.
Table 11 VLAN participation in Spanning Tree Groups
VLAN 1 VLAN 2
Switch A Spanning Tree Group 1
Port 17
Spanning Tree Group 2
Port 18
Switch B Spanning Tree Group 1
Port 17
Spanning Tree Group 2
Port 18
Configuring Multiple Spanning Tree Groups
This section explains how to assign each VLAN to its own Spanning Tree Group on the HP ProLiant BL p-Class
GbE2 Interconnect Switches A and B.
By default, Spanning Tree Groups 2-32 are empty, and Spanning Tree Group 1 contains all configured VLANs
until individual VLANs are explicitly assigned to other Spanning Tree Groups. Except for the default Spanning
Tree Group 1, which may contain more than one VLAN, Spanning Tree Groups 2-32 may contain only one
VLAN each.
NOTE: Each instance of Spanning Tree Group is enabled by default.