3Com 9100 Command to clear the FDB is as follows, Blackhole, Broadcast/Unknown Rate Limiting

104CHAPTER 7: QUALITY OF SERVICE (QOS)

The command to clear the FDB is as follows:

clear fdb

Blackhole

Using the blackhole option configures the switch to not forward any packets to the destination MAC address on any ports for the VLAN specified.

The blackhole option is configured using the following command:

create fdbentry 00:11:22:33:44:55 vlan default blackhole

Broadcast/Unknown Rate Limiting

It is possible to assign broadcast and unknown destination packets to a QoS profile that has the desired priority and bandwidth parameters. Broadcast/unknown rate limiting is an extension of the QoS feature used for destination MAC addresses.

For example, if you want to limit broadcast and unknown traffic on the VLAN default to the bandwidth and priority defined in QoS profile qp3, the command is:

create fdbentry ff:ff:ff:ff:ff:ff vlan default dynamic qp3

Verifying MAC-Based QoS Settings

To verify any of the MAC-based QoS settings, use either the command

show fdb perm

or the command

show qosprofile <qosname>

Packet Groupings This category of traffic groupings consists of prioritization bits used in IEEE 802.1p packets.