Router Vs. Layer 3 Switch

Routers and layer 3 switches have an overlapping set of functions, which creates a lot of confusion when it comes to selecting between them. In this article, a comparison is presented, which will make your job easier.
Techspirited Staff
Setting up a large computer network can be a daunting task and one needs an in-depth knowledge of the function of every networking device to build an efficient network. Two components which are quite similar in their working are routers and layer 3 switches.

What are Routers?

Routers are devices which control the transfer of intra-network and inter-network data traffic. These are intelligent microprocessor-controlled devices which carry out the decision making involved in transferring data traffic to the right addresses on networks.

It connects multiple networks together and comes in various types, depending on the scale, complexity, and number of networks that it handles. It works using a configuration table that has a list of network addresses in it. In networking terminology, it operates at layer 3 of the OSI model.

A router must inspect the data packets that come into a network and choose the most optimum path for transferring the data, according to the status of other packets on the network. Since it operates at the network layer, it uses the IP addresses of connected machines to send data packets to their right destinations. A wireless router used on networks, comes with a built-in firewall and a wireless encryption mechanism, designed to restrict access to the network.

What are Layer 3 Switches?

These switches perform all the functions that are carried out by routers, which includes directing data packets to their right destinations. Network switches are normally confined to work on the layer 2 of the OSI model, connecting network segments together. A layer 3 switch is a cross between a router and switch. It is a switch working on level 3.

These switches possess the fast-switching hardware of layer 2 switches, with the logical routing capabilities of a router. They inherit the best of both devices and were primarily created to carry out high-speed data transfers over local area networks. They are a lot different from basic layer 2 network switches.

Prime Differences

The main difference between a router and this switch type, lies in the fact that the latter uses hardware in implementing the packet routing over the network. What the router achieves through software manipulations, the layer 3 switch achieves through hardware level manipulations, which makes it operate faster. The switching hardware or forwarding architecture, which brings the high operation speeds of switches to layer 3 data transfers, is the prime difference between the two.

Being designed to operate on wide area networks, routers come with WAN ports. Since layer 3 switches are operated on local area networks, they do not come with any WAN features whatsoever. The cost of these switches is a fraction of router cost. So, if you need a routing device for your corporate intranet, what you go for is this switch type.

The layer 3 switch is basically a hybrid between a router and a switch, incorporating the software logic of the former and the hardware-level switching capabilities of the latter, ultimately providing faster routing. What the router achieves through software level manipulations, this switch implements through dynamic changes in hardware.

Unlike a router, a layer 3 switch doesn't possess wide area network ports or any other WAN-related features as it is designed to operate on local area networks. Lastly, they cost substantially lesser than routers while carrying out all of their functions on local area networks at higher speeds.