H3C S7500E Series Ethernet Switches Operation Manual

Operation Manual – MAC Address Table Management
H3C S7500E Series Ethernet Switches
Chapter 1 MAC Address Table Management
Configuration
1-2
 Note:
Dynamically learned MAC addresses cannot overwrite static MAC address entries, but
the latter can overwrite the former.
As shown in
Figure 1-1, when forwarding a frame, the device looks up the MAC
address table. If an entry is available for the destination MAC address, the device
forwards the frame directly from the hardware. If not, it does the following:
1) Broadcast the frame.
2) After the frame reaches the destination, the destination sends back a response
with its MAC address. (If no response is received, the frame will be dropped.)
3) Upon receipt of the response, the device adds an entry in the MAC address table,
indicating from which port the frames destined for the MAC address should be
sent.
4) Forward subsequent frames destined for the same MAC address directly from the
hardware.
5) If the frame cannot reach the destination device, the switch is still unable to learn
the MAC address table entries of the destination device and therefore broadcasts
the frames destined to this device afterwards.
Port 1 Port 2
MAC address Port
MAC A 1
MAC B 1
MAC C 2
MAC D 2
MAC A
MAC B
MAC C
MAC D
Figure 1-1 Forward frames using the MAC address table
1.2 Configuring MAC Address Table Management
This section covers these topics:
z Configuring MAC Address Entries
z Disabling Global MAC Address Learning
z Disabling MAC Address Learning on an Ethernet Port or Port Group
z Configuring MAC Address Aging Timer
z Configuring Maximum Number of MAC Addresses an Ethernet Port or a Port
Group Can Learn