3Com 2928 User Guide - Page 227

Item Description Instance Instance ID Port Priority Auto Path Cost Manual Path Cost Set the priority and path cost of the port in the current MSTI. z The priority of a port is an important factor in determining whether the port can be elected as the root port of a device. If all other conditions are the same, the port with the highest priority will be elected as the root port. On an MSTP-enabled device, a port can have different priorities in different MSTIs, and the same port can play different roles in different MSTIs, so that data of different VLANs can be propagated along different physical paths, thus implementing per-VLAN load balancing. You can set port priority values based on the actual networking requirements. z Path cost is a parameter related to the rate of a port. On an MSTP-enabled device, a port can have different path costs in different MSTIs. Setting appropriate path costs allows VLAN traffic flows to be forwarded along different physical links, thus achieving VLAN-based load balancing. The device can automatically calculate the default path cost; alternatively, you can also manually configure path cost for ports. Point to Point Specify whether the port is connected to a point-to-point link. z Auto: Automatically detects whether the link type of the port is point-to-point. z Force False: Specifies that the link type for the port is not point-to-point link. z Force True: Specifies that the link type for the port is point-to-point link. Advanced Transmit Limit MSTP Mode Select port(s) If a port is configured as connecting to a point-to-point link, the setting takes effect for the port in all MSTIs. If the physical link to which the port connects is not a point-to-point link and you force it to be a point-to-point link by configuration, the configuration may incur a temporary loop. Configure the maximum number of MSTP packets that can be sent during each Hello interval. The larger the transmit limit is, the more network resources will be occupied. Therefore, you are recommended to use the default value. Set whether the port migrates to the MSTP mode. In a switched network, if a port on an MSTP (or RSTP) device connects to a device running STP, this port will automatically migrate to the STP-compatible mode. After the device running STP is removed, the port on the MSTP (or RSTP) device may not be able to migrate automatically to the MSTP (or RSTP) mode, but will remain working in the STP-compatible mode. You can set this option to enable the port to automatically migrate to the MSTP (or RSTP) mode. Select one or multiple ports on which you want to configure MSTP on the chassis front panel. If aggregate interfaces are configured on the device, the page displays a list of aggregate interfaces below the chassis front panel. You can select aggregate interfaces from this list. 1-20