D-Link DGS-3308FG Product Manual - Page 40

8-port Gigabit Ethernet Switch User's Guide switch - lower numbers give a higher priority and a greater chance of a given switch being elected as the root bridge Hello Time The length of time between broadcasts of the hello message by the switch 2 seconds Maximum Age Timer Measures the age of a received BPDU for a port and ensures that the BPDU is discarded when its age exceeds the value of the maximum age timer. 20 seconds Forward Timer Delay The amount time spent by a port in the learning and listening states waiting for a BPDU that may return the port to the blocking state. 15 seconds Table 5-7. STP Parameters - Switch Level The following are the user-configurable STP parameters for the port or port group level: Variable Description Default Value Port Priority A relative priority for each port - lower numbers give a higher priority and a greater chance of a given port being elected as the root port 32768 Port Cost A value used by STP to evaluate paths - STP calculates path costs and selects the path with the minimum cost as the active path. 19 - 100Mbps Fast Ethernet ports 4 - 1000Mbps Gigabit Ethernet ports Table 5-8. STP Parameters - Port Group Level Bridge Protocol Data Units For STP to arrive at a stable network topology, the following information is used: • The unique switch identifier • The path cost to the root associated with each switch port • The port identifier STP communicates between switches on the network using Bridge Protocol Data Units (BPDUs). Each BPDU contains the following information: • The unique identifier of the switch that the transmitting switch currently believes is the root switch 30