ZyXEL NetAtlas User Guide - Page 178

Chapter 14 Switch Configuration The following table describes the labels in this screen. Table 86 Switch Configuration > STP: (M)RSTP LABEL DESCRIPTION Spanning Tree Protocol You can activate one of the STP modes on the device. Select RSTP, MRSTP or MSTP. Apply Click Apply to save your changes in this section. Enable RSTP Select this check box to activate RSTP. Active This field is available only when you select RSTP in the Spanning Tree Protocol field. Select this check box to activate an STP tree. Tree 1/2 This field is available only when you select MRSTP in the Spanning Tree Protocol field. This is a read only index number of the STP trees. Bridge Priority This field is available only when you select MRSTP in the Spanning Tree Protocol field. Bridge priority is used in determining the root device, root port and designated port. The device with the highest priority (lowest numeric value) becomes the RSTP root device. If all devices have the same priority, the device with the lowest MAC address will then become the root device. The allowed range is 0 to 61440 (32768 is the default). The lower the numeric value you assign, the higher the priority for this bridge. Hello Time (sec) Forward Delay (sec) Port Enable Priority Bridge Priority determines the root bridge, which in turn determines Max Age, Hello Time, and Forward Delay. This is the time interval in seconds between BPDU (Bridge Protocol Data Units) configuration message generations (by all devices in RSTP or the root device in STP). The allowed range is 1 to 10 seconds (2 is the default). This is the maximum time (in seconds) a device will wait before changing states. This delay is required because every device must receive information about topology changes before it starts to forward frames. In addition, each port needs time to listen for conflicting information that would make it return to a blocking state; otherwise, temporary data loops might result. The allowed range is 4 to 30 seconds (15 is the default). This field displays the Ethernet port number. Select this check box to activate (M)RSTP on this port. Configure the priority for each port here. Path Cost Priority decides which port should be disabled when more than one port forms a loop in a switch. Ports with a higher priority numeric value are disabled first. The allowed range is between 0 and 255 and the default value is 128. Path cost is the cost of transmitting a frame on to a LAN through that port. It is recommended to assign this value according to the speed of the bridge. The slower the media, the higher the cost. 178 NetAtlas EPON Manager User's Guide