ZyXEL MES-3528 User Guide - Page 130

Chapter 13 Spanning Tree Protocol Table 29 Advanced Application > Spanning Tree Protocol > MRSTP (continued) LABEL Hello Time Max Age Forwarding Delay DESCRIPTION This is the time interval in seconds between BPDU (Bridge Protocol Data Units) configuration message generations by the root switch. The allowed range is 1 to 10 seconds. This is the maximum time (in seconds) the Switch can wait without receiving a BPDU before attempting to reconfigure. All Switch ports (except for designated ports) should receive BPDUs at regular intervals. Any port that ages out STP information (provided in the last BPDU) becomes the designated port for the attached LAN. If it is a root port, a new root port is selected from among the Switch ports attached to the network. The allowed range is 6 to 40 seconds. This is the maximum time (in seconds) the Switch will wait before changing states. This delay is required because every switch 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. As a general rule: Note: 2 * (Forward Delay - 1) >= Max Age >= 2 * (Hello Time + 1) Port This field displays the port number. * Settings in this row apply to all ports. Use this row only if you want to make some settings the same for all ports. Use this row first to set the common settings and then make adjustments on a port-by-port basis. Active Edge Note: Changes in this row are copied to all the ports as soon as you make them. Select this check box to activate STP on this port. Select this to set the specified port as an edge port, allowing it to immediately transition to a forwarding state and bypass the listening and learning states. Priority Path Cost Tree Note: Device(s) may loop on boot up or when you plug/unplug port if the ring ports enable edge port. Configure the priority for each port here. 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-see Table 24 on page 118 for more information. Select which STP tree configuration this port should participate in. 130 MES-3528 User's Guide