D-Link DES-3828 Product Manual - Page 94

xStack DES-3800 Series Layer 3 Stackable Fast Ethernet Managed Switch CLI Manual 12 PACKET STORM CONTROL COMMANDS On a computer network, packets such as Multicast packets and Broadcast packets continually flood the network as normal procedure. At times, this traffic may increase do to a malicious endstation on the network or a malfunctioning device, such as a faulty network card. Thus, switch throughput problems will arise and consequently affect the overall performance of the switch network. To help rectify this packet storm, the Switch will monitor and control the situation. The packet storm is monitored to determine if too many packets are flooding the network, based on the threshold level provided by the user. Once a packet storm has been detected, the Switch will drop packets coming into the Switch until the storm has subsided. This method can be utilized by selecting the Drop option of the Action field in the window below. The Switch will also scan and monitor packets coming into the Switch by monitoring the Switch's chip counter. This method is only viable for Broadcast and Multicast storms because the chip only has counters for these two types of packets. Once a storm has been detected (that is, once the packet threshold set below has been exceeded), the Switch will shutdown the port to all incoming traffic with the exception of STP BPDU packets, for a time period specified using the CountDown field. If this field times out and the packet storm continues, the port will be placed in a Shutdown Forever mode which will produce a warning message to be sent to the Trap Receiver. Once in Shutdown Forever mode, the only method of recovering this port is to manually recoup it using the Port Configuration window in the Administration folder and selecting the disabled port and returning it to an Enabled status. To utilize this method of Storm Control, choose the Shutdown option of the Action field in the window below. The broadcast storm control commands in the Command Line Interface (CLI) are listed (along with the appropriate parameters) in the following table. Command Parameters config traffic control [ | all] {broadcast [enable | disable] | multicast [enable | disable] | Unicast [enable | disable] | action [drop | shutdown] | threshold | time_interval | countdown [0 | ]} show traffic control {[all | ]} config traffic control_trap [none | storm_occurred | storm_cleared | both] Each command is listed, in detail, in the following sections. config traffic control Purpose Syntax Description Parameters Used to configure broadcast/multicast/Unicast packet storm control. The software mechanism is provided to monitor the traffic rate in addition to the hardware storm control mechanism previously provided. config traffic control [ | all ] { broadcast [enable| disable]| multicast [enable| disable] | unicast [enable | disable] | action [drop | shutdown] | threshold |time_interval | countdown } This command is used to configure broadcast/multicast/Unicast storm control. By adding the new software traffic control mechanism, the user can now use both a hardware and software mechanism, the latter of which will now provide shutdown, recovery and trap notification functions for the Switch. − Used to specify a range of ports to be configured for traffic control. all − Specifies all ports are to be configured for traffic control on the Switch. broadcast [enable | disable] − Enables or disables broadcast storm control. multicast [enable | disable] − Enables or disables multicast storm control. Unicast [enable | disable] − Enables or disables traffic control. 90