Allied Telesis AT-GS950/10PS - Manual (Page 366)

Appendix A: MSTP Overview
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Region 1 VLANs Region 2 VLANs
Accounting Accounting
Sales Sales
Pre-Sales Pre-Sales
Marketing Technical Support
Product Management Software Engineering
Project Management Hardware Engineering
The two regions share three VLANs: Accounting, Sales, and Presales. You
can group these three VLANs into the same MSTI in each region. For
instance, for Region 1 you might group the three VLANs in MSTI 12 and in
Region 2 you could group them into MSTI 6. After they are grouped, you can
connect the VLANs across the regions using a link of untagged/tagged ports a
shown in Figure 145.
Figure 145. Spanning Regions without Blocking