Linux system VLAN, Layer 3 switching and trunk difference

In Linux systems, VLANs, Layer 3 switching, and trunks are three confusing concepts. If you only know a little about these three concepts, you will inevitably go around some detours and waste a lot of time. This article will introduce you to the differences between Linux system VLAN, Layer 3 switching and Trunk.

1.VLAN and triple nothing to

If not to mention Trunk and pure VLAN Ethernet switch will actually combine multiple Layer-2 became a , controlled by software. The merged switch is a VLAN-capable switch, and multiple physical switches participating in the merge are now degraded into logical switches. Multiple physical switches are not a silly merger. Another meaning of VLAN switches is that you can specify which physical port belongs to which logical switch through various policies. If you let the physical switch implement this, you have to deal with the problems of purchase, wiring, etc. This shows that software is really more flexible than hardware. Based on software, hardware is actually solidified software.

If you want to understand the meaning of VLAN, you can configure several Bridges on Linux. We know that Linux has a built-in soft Bridge implementation, which can be configured through brctl. A single Linux physical host is configured with N Ethernet cards, so you can simply simulate the concept of VLAN (note that the essence of VLAN has not been introduced yet). Trunk):

a. Add a br0, add the network card 1/2/3;

b. Add a br1, add the network card 4/5/6;

c....

d. NIC 1 is connected to a pure Layer 2 switch 1;

e. NIC 4 is connected to a pure Layer 2 switch 2;

f....

There are multiple bridges on the Linux host. You can think of the Linux host as a machine that supports VLANs.

A VLAN switch is a pure Layer 2 device. However, if this is the case, there is no need to introduce the concept of VLAN. What is the difference between VLAN and the above simple configuration? This involves the IEEE802.1q standard, see the next section. Previous123Next page Total 3 pages