D-Link DGS-3130 User Manual - Page 136

DGS-3130 Series Layer 3 Stackable 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. 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 in 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 considers the topology to be loop free. Eventually, an alternate port that was previously a Blocking 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 an MSTI configured on the Switch. The Switch initially possesses one Common Internal Spanning Tree (CIST) of which the user may modify the parameters for but cannot change or delete the MSTI ID. To view the following window, click L2 Features > STP > MST Configuration Identification, as shown below: 126