Difference between Layer 2 and Layer 3 Switch.
Difference between Layer 2 and Layer 3 Switch.
1. Layer 2 and Layer 3 terms come from the OSI seven Layer model. Within the model, Layer 2 represents the “Data Link Layer” while Layer 3 represents the “Network Layer”.
2. Layer 3 switches are switches that can work at layer 2 or layer 3 or a combination of the two. Layer 2 switch routes packets based on MAC (48-bit physical) address, Layer 3 switch route data packets based on IP (32-bit logical) address.
3. The main beauty of a layer three switch is that it uses an ASIC (Application Specific Integrated Circuit) a hardware chip and is thus faster than software.
4. Traditional switching operates at layer 2 of the OSI model, where packets are sent to a specific switch port based on destination MAC addresses but can not send data to other network. Routing operates at layer 3, where packets are sent to a specific next machine’s IP address, based on destination IP address and can transfer data to any other network.
5. Layer 2 switches have the capability of moving packets around a single network. It is intelligent enough to learn the MAC addresses of each device, source/ destination of each packet within the single domain. It does not have the ability to transport the data packet from one network to another network and also can not prioritize packets to guarantee bandwidth. So putting devices on a Layer 3 switch makes one entire large local segment (or what some people might call a “broadcast domain”).
6. Layer 3 switches act like a traditional router – it enables different network segments to be linked together. With this, data can be inter-networked from one network subnet to another. Prioritization of packets can be setup and the Layer 3 switch is intelligent enough to learn which routes are the best between the networks.
7. Layer 3 switches have the capability to logically separate networks into two or more VLANs (Virtual LANs), enhancing security and unauthorized access between networks. A Layer 3 switch typically sits above Layer 2 switches and manages the routes/ access between the different networks.
8. L3 switch as its name suggest it has L3 capabilities you can run routing protocol on them. L3 switch used to route traffic and it is more reliable then router because it rely on single link to route traffic and if that link failed your whole connectivity is failed. L3 are more expensive than L2 switch.
9. Each large network can be divided in mini network and can easily controlled by its own Layer 2 switches. But all mini networks need the ability to synchronize, coordinate and share data with each other to perform the relevant operations, there needs to be a device that allows each data to move from one mini network to another. That is where the Layer 3 switch comes in. All Layer 2 switches essentially converges to the Layer 3 switch facilitating inter-network data transport with the ability to prioritize packets, allow/ limit access to certain networks at any given time.
10. Some advantages of Layer 2 include lower costs, only require switching, no routing gear is necessary and offers very low latency (delay) that means it takes minimum time to get packet from one point to another. Layer 2 also has some significant disadvantages such as the lack of router hardware, leaving them at risk to broadcast bunch of packets and can’t go beyond its single network. Layer 2 networks also forward all traffic, anything transmitted by one device is forwarded to all devices. When the network gets too large, the broadcast traffic begins to create congestion and decreases network efficiency.
11. Layer 3 devices restrict broadcast traffic to the local network. This reduces overall traffic levels by allowing administrators to divide networks into smaller parts and restrict broadcasts to only that sub-network.This means there is a limit to the size of a layer 2 network. However, a properly configured layer 3 network with the correct knowledge and hardware can have infinite growth.
12. A Layer 3 switch is a high-performance device for network routing. A router works with IP addresses at layer 3 of the model. Layer 3 networks are built to run on layer 2 networks. But it is slow in speed compare to layer 2 switch.
