D-Link DGS-1510 User Manual - Page 157

DGS-1510 Series Gigabit Ethernet SmartPro Switch Web UI Reference Guide Parameter Guard Timer Hold-Off Timer WTR Timer Description Select the checkbox and enter the guard timer value here. This value must be between 10 and 2000 milliseconds. By default, this value is 500 milliseconds. Select the checkbox and enter hold-off timer value here. This value must be between 0 and 10000 milliseconds. By default, this value is 0 milliseconds. Select the checkbox and enter the WTR timer value here. This value must be between 1 and 12 minutes. By default, this value is 5 minutes. Click the Back button to discard the changes made and return to the previous window. Click the Apply button to accept the changes made. Loopback Detection The Loopback Detection (LBD) function is used to detect the loop created by a specific port. This feature is used to temporarily shut down a port on the Switch when a CTP (Configuration Testing Protocol) packet has been looped back to the Switch. When the Switch detects CTP packets received from a port or a VLAN, this signifies a loop on the network. The Switch will automatically block the port or the VLAN and send an alert to the administrator. The Loopback Detection function can be implemented on a range of ports at a time. The user may enable or disable this function using the drop-down menu. To view the following window, click L2 Features > Loopback Detection, as shown below: Figure 5-55 Loopback Detection Window The fields that can be configured for Loopback Detection Global Settings are described below: Parameter Loopback Detection State Mode Enable VLAN ID List Description Select to enable or disable loopback detection. The default is Disabled. Select the loopback detection mode. Options to choose from are Port-based and VLAN-based. Enter the VLAN ID for loop detection. This only takes effect when the VLAN-based is selected in the Mode drop-down list. 146