Moxa Technologies EDS-405A Configuring STP/RSTP, 3-32, EDS-408A/405A Series User’s Manual, Block

EDS-408A/405A Series User’s Manual Featured Functions

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.

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

Switch A

VLAN1

VLAN2

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

Switch B	Block	Switch C
VLAN1	802.1Q tagged,	VLAN1
VLAN2		VLAN2
	10BaseTx
	half-duplex Link
	carries VLAN1, 2
	(path cost = 100)

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:

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