Well ….. Layer 3 Switch. What? Switches are endless? How is it?
Which is not? There are many types of switches. Wouldn’t it be nice to know all of them? As technology advances, so do devices. Similarly, a Layer 3 switch has many advantages over a Layer 2 switch. In fact, the Layer 3 Switch is a high-performance computer networking device used for network routing. The Layer 2 Switch works on Layer 2 (Data Link Layer). The Layer 3 switch also works on Layer 3 (Network Layer) of the OSI Model. In other words, Layer 3 switches are like routers. Layer 3 switches can support the same routing protocols as network routers. In addition, Layer 3 switches, like routers, make decisions based on the port level IP (Internet Protocol) address. To put it more simply, both routers and Layer 3 switches also use routing tables (IP Address Tables) to select routes. Layer 3 switches are designed to perform better than routers used in local area networks. Layer 3 switches and routers differ only in the hardware technology used to build them. But Layer 3 Switches are faster than routers. This is because Layer 3 switches are built on switching hardware. Layer 3 switches check for incoming packets and make dynamic routing decisions based on the source and destination (sender and receiver) addresses.
In fact, Layer 3 switches are designed to be used within your local network. Layer 3 switches do not have WAN (Wide Area Network) ports. This means that it is better to use Layer 3 switches for your Inter-VLAN (Virtual LAN) routing. For example, in one workplace there are different departments. Each department will be connected to a LAN (Locak Area Network). People on the same LAN are networked with each other. But I want to connect LANs to each other. In other words, they want to send data to each other on the LAN over there and on the LAN on this side. If you want to exchange data between different departments, you need to connect those LANs. It is best to use a Layer 3 Switch when connecting such LANs. Let me show you a picture to make it clearer.
In the image above, a Layer 3 switch is used to connect LANs. With this Layer 3 switch and LANs connected to each other, data can be exchanged between different LANs. It is also connected to a router connected to the Internet. In the picture, a LAN user sends data to a user on LAN 4. The data sent by LAN 1 then reaches the Layer 3 switch. They have to make decisions about which port of the LAN from the Layer 3 Switch to access the data directly to their destination. In other words, the Layer 3 Switch looks for the destination IP address of the incoming packet in its routing table. In that case, it is the IP address of LAN 4, so it is not sent to the other LAN 2, LAN 3, LAN 5, but directly to LAN 4. The data packet is received from the switch used on LAN 4 (eg Layer 2 Switch) and sent directly to the port where the data packet is to arrive. It also provides you with the shortest and fastest way to get there. Layer 3 switches use IP addresses (routing tables) for data packets to make these decisions.