3Com 9100 manual STPD2 contains VLANs Manufacturing and Engineering

STP Configurations 91

Care must be taken to ensure that multiple STPD instances within a single switch do not see each other in the same broadcast domain. This could happen if, for example, another external bridge is used to connect VLANs belonging to separate STPDs.

If you delete an STPD, the VLANs that were members of that STPD are also deleted. You must remove all VLANs associated with the STP before deleting the STPD.

If no VLANs are configured to use the protocol filter any on a particular port, STP BPDUs are not flooded within a VLAN when STP is turned off. If you need STP to operate on this type of port, enable STP on the associated VLAN, so that it can participate.

Defaults The default device configuration contains a single STPD called s0. The default VLAN is a member of STPD s0.

All STP parameters default to the IEEE 802.1D values, as appropriate.

STP Configurations When you assign VLANs to an STPD, pay careful attention to the STP configuration and its effect on the forwarding of VLAN traffic.

Figure 16 illustrates a network that uses VLAN tagging for trunk connections. The following four VLANs have been defined:

■Sales is defined on Switch A, Switch B, and Switch M.

■Personnel is defined on Switch A, Switch B, and Switch M.

■Manufacturing is defined on Switch Y, Switch Z, and Switch M.

■Engineering is defined on Switch Y, Switch Z, and Switch M.

■Marketing is defined on all switches (Switch A, Switch B, Switch Y, Switch Z, and Switch M).

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.