D-Link DGS-3120-24TC Product Manual - Page 88

xStack® DGS-3120 Series Managed Switch Web UI Reference Guide NNI BPDU Address Used to determine the BPDU protocol address for GVRP in service provide site. It can use 802.1d GVRP address, 802.1ad service provider GVRP address or a user defined multicast address. The range of the user defined address is 0180C2000000 - 0180C2FFFFFF. Click the Apply button to accept the changes made for each individual section. NOTE: The Bridge Hello Time cannot be longer than the Bridge Max Age. Otherwise, a configuration error will occur. Observe the following formulas when setting the above parameters: Bridge Max Age 2 x (Bridge Hello Time + 1 second) STP Port Settings STP can be set up on a port per port basis. To view the following window, click L2 Features > Spanning Tree > STP Port Settings, as show below: Figure 4-29 STP Port Settings window It is advisable to define an STP Group to correspond to a VLAN group of ports. The fields that can be configured are described below: Parameter Description Unit From Port / To Port External Cost (0=Auto) Select the unit you want to configure. Select the starting and ending ports to be configured. 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. 80