D-Link DGS-3200-16 User Manual - Page 96

xStack® DGS-3200 Series Layer 2 Gigabit Ethernet Managed Switch Figure 3 - 35. STP Port Settings window It is advisable to define an STP Group to correspond to a VLAN group of ports. The following STP Port Settings fields can be set: Parameter Description From Port The beginning port in a consecutive group of ports to be configured. To Port The ending port in a consecutive group of 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. State 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 pull-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 packets. If a BPDU packet is 83