Dell PowerConnect FCS624S Configuration Guide - Page 251

Configuring standard STP parameters 8 TABLE 48 Default STP bridge parameters (Continued) Parameter Description Default and valid values Hello Time Priority The interval of time between each configuration BPDU sent by the root bridge. 2 seconds Possible values: 1 - 10 seconds A parameter used to identify the root bridge in a spanning tree (instance of STP). The bridge with the lowest value has the highest priority and is the root. A higher numerical value means a lower priority; thus, the highest priority is 0. 32768 Possible values: 0 - 65535 NOTE If you plan to change STP bridge timers, Dell recommends that you stay within the following ranges, from section 8.10.2 of the IEEE STP specification. 2 * (forward_delay -1) >= max_age max_age >= 2 * (hello_time +1) Table 49 lists the default STP port parameters. The port parameters affect individual ports and are separately configurable on each port. TABLE 49 Default STP port parameters Parameter Description Default and valid values Priority Path Cost The preference that STP gives this port relative to other ports for forwarding traffic out of the spanning tree. A higher numerical value means a lower priority. 128 Possible values: 0 - 240 (configurable in increments of 16) The cost of using the port to reach the root bridge. When selecting among multiple links to the root bridge, STP chooses the link with the lowest path cost and blocks the other paths. Each port type has its own default STP path cost. 10 Mbps - 100 100 Mbps - 19 Gbps - 4 10 Gbps - 2 Possible values are 0 - 65535 Enabling or disabling the Spanning Tree Protocol (STP) STP is enabled by default on devices running Layer 2 code. STP is disabled by default on devices running Layer 3 code. You can enable or disable STP on the following levels: • Globally - Affects all ports and port-based VLANs on the device. • Port-based VLAN - Affects all ports within the specified port-based VLAN. When you enable or disable STP within a port-based VLAN, the setting overrides the global setting. Thus, you can enable STP for the ports within a port-based VLAN even when STP is globally disabled, or disable the ports within a port-based VLAN when STP is globally enabled. • Individual port - Affects only the individual port. However, if you change the STP state of the primary port in a trunk group, the change affects all ports in the trunk group. PowerConnect B-Series FCX Configuration Guide 209 53-1002266-01