User Manual

Configuration Examples
694
M4200 and M4300 Series ProSAFE Managed Switches Web Management User Manual
If you do not specify a root bridge and all switches are assigned the same bridge priority
value, the switch with the lowest MAC address is elected as the root bridge (see
Configure CST Settings on page 206).
5. From the CST Port Configuration page, select ports 1/0/1–1/0/8 and select Enable from the
STP Status menu (see Configure CST Port Settings on page 208).
6. Click the Apply button.
7. Select ports 1/0/1–1/0/5 (edge ports), and select Enable from the Fast Link menu.
Since the edge ports are not at risk for network loops, ports with Fast Link enabled
transition directly to the Forwarding state.
8. Click the Apply button.
You can use the CST Port Status page to view spanning tree information about each port.
9. From the MST Configuration page, create a MST instances with the following settings:
• MST ID: 1
• Priority: Use the default (32768)
• VLAN ID: 300
For more information, see Configure MST Settings on page 213.
10. Click the Add button.
11. Create a second MST instance with the following settings
• MST ID: 2
• Priority: 49152
• VLAN ID: 500
12. Click the Add button.
In this example, assume that Switch 1 has become the Root bridge for the MST instance 1,
and Switch 2 has become the Root bridge for MST instance 2. Switch 3 has hosts in the
Sales department (ports 1/0/1, 1/0/2, and 1/0/3) and in the HR department (ports 1/0/4 and
1/0/5). Switches 1 and 2 also include hosts in the Sales and Human Resources departments.
The hosts connected from Switch 2 use VLAN 500, MST instance 2 to communicate with the
hosts on Switch 3 directly. Likewise, hosts of Switch 1 use VLAN 300, MST instance 1 to
communicate with the hosts on Switch 3 directly.
The hosts use different instances of MSTP to effectively use the links across the switch. The
same concept can be extended to other switches and more instances of MSTP.