Extreme Networks Summit1 manual Switch a Switch B, Switch Y Switch Z Switch M

STP CONFIGURATIONS

Two STPDs are defined:

•STPD1 contains VLANs Sales and Personnel.

•STPD2 contains VLANs Manufacturing and Engineering.

The VLAN Marketing is a member of the default STPD, but not assigned to either STPD1 or STPD2.

Sales, Personnel, Marketing

Switch A

Switch B

STPD 1

Manufacturing, Engineering, Marketing

Switch Y

Switch Z

Switch M STPD 2

Sales, Personnel, Manufacturing, Engineering, Marketing

Figure 7-1:Multiple Spanning Tree Domains

When the switches in this configuration start up, STP configures each STP domain such that there are no active loops in the topology. STP could configure the topology in a number of ways to make it loop-free.

In Figure 7-1, the connection between Switch A and Switch B is put into blocking state, and the connection between Switch Y and Switch Z is put into blocking state. After STP converges, all the VLANs can communicate, and all bridging loops are prevented.

The VLAN Marketing, which has not been assigned to either STPD1 or STPD2, communicates using all five switches. The topology has no loops, because STP has already blocked the port connection between Switch A and Switch B, and between Switch Y and Switch Z.

SUMMIT SWITCH INSTALLATION AND USER GUIDE 7-3