Moxa Technologies EDS-405A User Manual

 

has a port cost of 100 and is automatically blocked because the other Switch-to-Switch 
connections have a port cost of 36 (18+18). This means that both VLANs are now 
subdivided—VLAN 1 on Switch units A and B cannot communicate with VLAN 1 on Switch C, 
and VLAN 2 on Switch units A and C cannot communicate with VLAN 2 on Switch B. 

Block

Switch A

Switch B

Switch C

VLAN1

VLAN2

802.1Q tagged,
10BaseTx
half-duplex Link
carries VLAN1, 2
(path cost = 100)

100BaseTX
full-duplex Link;
only carries VLAN2
(path cost = 18)

100BaseTX
full-duplex Link;
only carries VLAN1
(path cost = 18)

VLAN1

VLAN2

VLAN1

VLAN2

 

To avoid subdividing VLANs, all inter-switch connections should be made members of all 
available 802.1Q VLANs. This will ensure connectivity at all times. For example, the connections 
between Switches A and B, and between Switches A and C should be 802.1Q tagged and carrying 
VLANs 1 and 2 to ensure connectivity. 

Configuring STP/RSTP 

The following figures indicate the Spanning Tree Protocol parameters that can be configured. A 
more detailed explanation of each parameter is given below the figure. (NOTE: The user interface 
for EDS-408A shows 8 ports.) 

 

At the top of this page, the user can check the Current Status of this function. For RSTP, you will 
see: