Allied Telesis AT-S60 - Manual (Page 227)

Chapter 12: STP, RSTP, and MSTP
Section II: Local and Telnet Management 226
Here is an example. Let’s assume that you have two regions that contain
the following VLANS:
Region 1 VLANs Region 2 VLANs
Sales Hardware Engineering
Presales Software Engineering
Marketing Technical Support
Advertising Product Management
Technical Support CAD Development
Product Management Accounting
Project Management
Accounting
The two regions share three VLANs: Technical Support, Product
Management, and Accounting. You could group those VLANs into the
same MSTI in each region. For instance, for Region 1 you might group
the three VLANs in MSTI 11 and in Region 2 you could group them into
MSTI 6. Once grouped, you can connect the VLANs across the regions
using a link of tagged ports.