D-Link DGS-3130 User Manual - Page 135

DGS-3130 Series Layer 3 Stackable Managed Switch Web UI Reference Guide Figure 5-47 STP Port Settings Window The fields that can be configured are described below: Parameter Unit From Port - To Port Cost State Guard Root Link Type Port Fast Description Select the Switch unit that will be used for this configuration here. Select the range of ports that will be used for this configuration here. Enter the cost value here. This value must be between 1 and 200000000. This value 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, a Gigabit port is 20000, and a 10 Gigabit port is 2000. The lower the number, the greater the probability the port will be chosen to forward packets. Select to enable or disable the STP port state. Select to enable or disable the Guard Root function. Select the Link Type option here. Options to choose from are Auto, P2P, and Shared. A full-duplex port is considered to have a Point-to-Point (P2P) connection. Alternatively, a half-duplex port is considered to have a Shared connection. The port cannot transit into the forwarding state rapidly by setting the link type to Shared. By default this option is Auto. Select the Port Fast option here. Options to choose from are Network, Disabled, and Edge.  In the Network mode the port will remain in the non-port-fast state for three seconds. The port will change to the port-fast state if no BPDU is received and changes to the forwarding state. If the port received the BPDU later, it will change to the non-port-fast state.  In the Disable mode, the port will always be in the non-port-fast state. It will always wait for the forward-time delay to change to the forwarding state.  In the Edge mode, the port will directly change to the spanning-tree forwarding state when a link-up occurs without waiting for the forward-time delay. If the interface receives a BPDU later, its operation state changes to the non-port-fast state. By default, this option is Network. 125