PLANET WGSW-50040 - Manual (Page 217)

26-1
Chapter 26 The Number Limitation Function
of Port, MAC in VLAN Configuration
26.1 Introduction to the Number Limitation Function of Port,
MAC in VLAN
MAC address list is used to identify the mapping relationship between the destination MAC addresses and the
ports of switch. There are two kinds of MAC addresses in the list: static MAC address and dynamic MAC
address. The static MAC address is set by users, having the highest priority (will not be overwritten by
dynamic MAC address), and will always be effective; dynamic MAC address is learnt by the switch through
transmitting data frames, and will only be effective in a specific time range. When the switch receives a data
framed waiting to be transmitted, it will study the source MAC address of the data frame, build a mapping
relationship with the receiving port, and then look up the MAC address list for the destination MAC address. If
any matching list entry is found, the switch will transmit the data frame via the corresponding port, or, the
switch will broadcast the data frame over the VLAN it belongs to. If the dynamically learnt MAC address
matches no transmitted data in a long time, the switch will delete it from the MAC address list.
Usually the switch supports both the static configuration and dynamic study of MAC address, which means
each port can have more than one static set MAC addresses and dynamically learnt MAC addresses, and
thus can implement the transmission of data traffic between port and known MAC addresses. When a MAC
address becomes out of date, it will be dealt with broadcast. No number limitation is put on MAC address of
the ports of our current switches; every port can have several MAC addressed either by configuration or study,
until the hardware list entries are exhausted. To avoid too many MAC addresses of a port, we should limit the
number of MAC addresses a port can have.
To summer up, it is very meaningful to develop the number limitation function of port, MAC in VLAN. Switch
can control the number of MAC address of ports and VLAN through configuration commands.
Limiting the number of dynamic MAC of ports:
1. Limiting the number of dynamic MAC. If the number of dynamically learnt MAC address of VLAN by the
switch is already larger than or equal with the max number of dynamic MAC address, then shutdown the MAC
study function on all ports of VLAN, otherwise, the port can continue its study. (except special ports)
26.2 The Number Limitation Function of Port, MAC in VLAN
Configuration Task Sequence
1. Enable the number limitation function of MAC on ports
2. Enable the number limitation function of MAC in VLAN