Dell PowerConnect 3048 User Manual page 36

Dynamic Addresses
The Dynamic Addresses lookup table allows you to view the MAC addresses that are currently in the address database. When addresses are in the database,
the packets intended for those addresses are forwarded directly to those ports. You can filter out the table by port, VLAN, and MAC address by checking those
fields.
Dynamic MAC address learning is enabled by default. This is the standard mode for a network switch. In some networks, you may want to create a secured
network by disabling the dynamic address learning capabilities. When this is done, all current dynamic address entries will be locked in. These addresses will
not age out and new addresses will not be learned. In addition, if a new address is detected on a port, the switch will disable the port with the new address,
save the current settings to NVRAM, and send out a Simple Network Management Protocol (SNMP) trap warning. This is useful for locking out systems that
attempt to access the network that were not on the network previous to the lockdown. Once a port is automatically disabled, you can reenable the port
manually. The NVRAM will only be saved the first time a given port detects a new address. If the aging time is raised prior to disabling the dynamic address
learning, it will allow enough time for all current MAC address to be learned by the switch without the possibility of aging out.
Address Aging
In the Address Aging screen, you can specify how long an address stays available in the bridge tables. The timer can be set to the minimum and maximum
values range indicated within parentheses.
Static Multicast Groups Administration
Static multicast is a way to manage multicast traffic. Each multicast address can be assigned ports that will participate in that multicast group. Ports that are
added to a multicast group will forward all multicast packets from the specified multicast address to the other ports in that group. The administration page is
where multicast addresses are added.