SNR S2989G-48TX-RPS — настройка и управление MAC-адресами в сетевых коммутаторах [156/553]
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SNR S2989G-48TX-RPS — настройка и управление MAC-адресами в сетевых коммутаторах [156/553]

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SNR S2989G-24TX [156/553] Forward or filter
2-92
S2989G-24TX Operation Manual Chapter 2 Layer 2 services
Configuration
as the destination MAC address is 00-01-33-33-33-33, only PC3 will reply to PC1.
When port 1/0/12 receives the message sent by PC3, a mapping entry for MAC
address 00-01-33-33-33-33 and port 1/0/12 is added to the MAC table.
4. Now the MAC table has two dynamic entries, MAC address 00-01-11-11-11-11 - port
1/0/5 and 00-01-33-33-33-33 -port1/0/12.
5. After the communication between PC1 and PC3, the switch does not receive any
message sent from PC1 and PC3. And the MAC address mapping entries in the MAC
table are deleted in 300 to 2*300 seconds (ie, in single to double aging time). The 300
seconds here is the default aging time for MAC address entry in switch. Aging time
can be modified in switch.
2.21.1.2 Forward or Filter
The switch will forward or filter received data frames according to the MAC table.
Take the above figure as an example, assuming switch have learnt the MAC address of
PC1 and PC3, and the user manually configured the mapping relationship for PC2 and
PC4 to ports. The MAC table of switch will be:
1. Forward data according to the MAC table
If PC1 sends a message to PC3, the switch will forward the data received on port
1/0/5 from port1/0/12.
2. Filter data according to the MAC table
If PC1 sends a message to PC2, the switch, on checking the MAC table, will find PC2
and PC1 are in the same physical segment and filter the message (i.e. drop this
message).
Three types of frames can be forwarded by the switch:
Broadcast frame
Multicast frame
Unicast frame
The following describes how the switch deals with all the three types of frames:
1. Broadcast frame: The switch can segregate collision domains but not broadcast
domains. If no VLAN is set, all devices connected to the switch are in the same
broadcast domain. When the switch receives a broadcast frame, it forwards the
frame in all ports. When VLANs are configured in the switch, the MAC table will
MAC Address
Port number
Entry added by
00-01-11-11-11-11
1/0/5
Dynamic learning
00-01-22-22-22-22
1/0/5
Static configuration
00-01-33-33-33-33
1/0/12
Dynamic learning
00-01-44-44-44-44
1/0/12
Static configuration

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Узнайте, как коммутаторы обрабатывают MAC-адреса, включая динамическое обучение и фильтрацию данных. Понимание работы с таблицами MAC поможет оптимизировать сетевые настройки.