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DWS-3160 Series Gigabit Ethernet Unified Switch Web UI Reference Guide

Figure 7-29 STP Port Settings window

The fields that can be configured are described below:

Parameter Description

From Port / To Port

Select the starting and ending ports to be configured.

External Cost

(0=Auto)

This defines a metric that indicates the relative cost of forwarding packets to the

specified port list. Port cost can be set automatically or as a metric value. The default

value is 0 (auto). Setting 0 for the external cost will automatically set the speed for

forwarding packets to the specified port(s) in the list for optimal efficiency. The default

port cost for a 100Mbps port is 200000 and the default port cost for a Gigabit port is

20000. Enter a value between 1 and 200000000 to determine the External Cost. The

lower the number, the greater the probability the port will be chosen to forward

packets.

P2P Choosing the True parameter indicates a point-to-point (P2P) shared link. P2P ports

are similar to edge ports; however they are restricted in that a P2P port must operate

in full duplex. Like edge ports, P2P ports transition to a forwarding state rapidly thus

benefiting from RSTP. A P2P value of False indicates that the port cannot have P2P

status. Auto allows the port to have P2P status whenever possible and operate as if

the P2P status were True. If the port cannot maintain this status, (for example if the

port is forced to half-duplex operation) the P2P status changes to operate as if the

P2P value were False. The default setting for this parameter is Auto.

Restricted TCN

Topology Change Notification is a simple BPDU that a bridge sends out to its root

port to signal a topology change. Restricted TCN can be toggled between True and

False. If set to True, this stops the port from propagating received topology change

notifications and topology changes to other ports. The default is False.

Migrate When operating in RSTP mode, selecting Yes forces the port that has been selected

to transmit RSTP BPDUs.

Port STP

This drop-down menu allows you to enable or disable STP for the selected group of

ports. The default is Enabled.

Forward BPDU

Use the drop-down menu to enable or disable the flooding of BPDU packets when

STP is disabled.

Edge Choosing the True parameter designates the port as an edge port. Edge ports cannot

create loops, however an edge port can lose edge port status if a topology change

creates a potential for a loop. An edge port normally should not receive BPDU