What is physical isolation:
The so-called “physical isolation” means that there is no mutual data interaction between two or more networks, and there is no contact at the physical layer/data link layer/IP layer. The purpose of physical isolation is to protect the hardware entities and communication links of each network from natural disasters, man-made sabotage and wiretapping attacks. For example, the physical isolation of the internal network and the public network can truly ensure that the internal information network is not attacked by hackers from the Internet.

What is logical isolation:
The logical isolator is also an isolation component between different networks. There are still data channel connections on the physical layer/data link layer at the isolated ends, but technical means are used to ensure that there are no data channels at the isolated ends, that is, logically. Isolation, the logical isolation of network optical transceivers/switches on the market is generally achieved by dividing VLAN (IEEE802.1Q) groups;

VLAN is equivalent to the broadcast domain of the second layer (data link layer) of the OSI reference model, which can control the broadcast storm within a VLAN. After dividing the VLAN, due to the reduction of the broadcast domain, the isolation of two different VLAN grouping network ports is realized.

Advantages of physical isolation over logical isolation:
1. Each network is an independent channel, has no influence on each other, and does not interact with data;
2. Each network is an independent channel bandwidth, how much bandwidth comes in, how much bandwidth is in the transmission channel;