User's Manual

Configuration Guide of XGS-5240-Series
48-1
Chapter 48 The Number Limitation
Function of MAC and IP in Port, VLAN
Configuration
48.1 Introduction to the Number Limitation Function
of MAC and IP in Port, VLAN
MAC address list is used to identify the mapping relationship between the destinati
on 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 tra
nsmitting data frames, and will only be effective in a specific time range. When the swi
tch receives a data framed waiting to be transmitted, it will study the source MAC addr
ess of the data frame, build a mapping relationship with the receiving port, and then lo
ok 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 swi
tch 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 fro
m 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 a
nd 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 When a MAC address becomes out
of date, it will be dealt with broadcast.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 ma
ny MAC addresses of a port, we should limit the number of MAC addresses a port ca
n have.
For each INTERFACE VLAN, there is no number limitation of IP; the upper limit of
the number of IP is the upper limit of the number of user on an interface, which is, a
t the same time, the upper limit of ARP and ND list entry. There is no relative configur
ation command can be used to control the sent number of these list entries. To enhan
ce the security and the controllability of our products, we need to control the number o