Dell PowerSwitch S4820T Configuration Guide for the S4820T System 9.100.0 - Page 842

Table 92. STP Default Values STP Parameters Forward Delay Hello Time Max Age Port Cost • 100-Mb/s Ethernet interfaces • 1-Gigabit Ethernet interfaces • 10-Gigabit Ethernet interfaces • 40-Gigabit Ethernet interfaces • Port Channel with 100 Mb/s Ethernet interfaces • Port Channel with 1-Gigabit Ethernet interfaces • Port Channel with 10-Gigabit Ethernet interfaces • Port Channel with 40-Gigabit Ethernet interfaces Default Value 15 seconds 2 seconds 20 seconds • 200000 • 20000 • 2000 • 1400 • 180000 • 18000 • 1800 • 600 Port Priority 8 • Change the forward-delay parameter (the wait time before the interface enters the Forwarding state). PROTOCOL SPANNING TREE mode forward-delay seconds The range is from 4 to 30. The default is 15 seconds. • Change the hello-time parameter (the BPDU transmission interval). PROTOCOL SPANNING TREE mode hello-time seconds NOTE: With large configurations (especially those with more ports) Dell Networking recommends increasing the hellotime. The range is from 1 to 10. the default is 2 seconds. • Change the max-age parameter (the refresh interval for configuration information that is generated by recomputing the spanning tree topology). PROTOCOL SPANNING TREE mode max-age seconds The range is from 6 to 40. The default is 20 seconds. To view the current values for global parameters, use the show spanning-tree 0 command from EXEC privilege mode. Refer to the second example in Enabling Spanning Tree Protocol Globally. Modifying Interface STP Parameters You can set the port cost and port priority values of interfaces in Layer 2 mode. • Port cost - a value that is based on the interface type. The greater the port cost, the less likely the port is selected to be a forwarding port. 842 Spanning Tree Protocol (STP)