D-Link DXS-3400 User Manual - Page 154

DXS-3400 Series Lite Layer 3 Stackable 10GbE Managed Switch Web UI Reference Guide Parameter TCN Filter BPDU Forward Priority Hello Time Loop Guard Description Select to enable or disable the TCN filter option. Enabling TC filtering on a port is useful for an ISP to prevent the external bridge to a core region of the network, causing address flushing in that region, possibly because those bridges are not under the full control of the administrator. When a port is set to the TCN filter mode, the TC event received by the port will be ignored. By default, this option is Disabled. Select to enable or disable BPDU forwarding. If enabled, the received STP BPDU will be forwarded to all VLAN member ports in the untagged form. By default, this option is Disabled. Select the priority value here. Options to choose from are 0 to 240. By default this option is 0. A lower value has higher priority. Enter the hello time value here. This value must be between 1 and 2 seconds. This value specifies the interval that a designated port will wait between the periodic transmissions of each configuration message. Select to enable or disable the loop guard feature on the specified port(s) here. The STP loop guard feature provides additional protection against Layer 2 forwarding loops (STP loops). An STP loop is created when an STP blocking port in a redundant topology erroneously transitions to the forwarding state. This usually happens because one of the ports of a physically redundant topology (not necessarily the STP blocking port) no longer receives STP BPDUs. In its operation, STP relies on continuous reception or transmission of BPDUs based on the port role. The designated port transmits BPDUs, and the non-designated port receives BPDUs. When one of the ports in a physically redundant topology no longer receives BPDUs, the STP conceives that the topology is loop free. Eventually, the blocking port from the alternate or backup port becomes designated and moves to a forwarding state. This situation creates a loop. Click the Apply button to accept the changes made. MST Configuration Identification This window is used to display and configure the MST configuration identification settings. These settings will uniquely identify a multiple spanning tree instance set on the Switch. The Switch initially possesses one CIST, or Common Internal Spanning Tree, of which the user may modify the parameters for but cannot change the MSTI ID for, and cannot be deleted. To view the following window, click L2 Features>STP> MST Configuration Identification, as shown below: 144