What is the difference between router and layer 3 switch

Of a layer 3 switch, layer forwarding is performed by specialized ASICs — it is faster than routers, but they usually lack some of the advanced functionalities of routers.

Router is a ubiquitous hardware applied in home and small business networks. It allows communication between devices that attached to it and the internet. A router can forward traffic packets based on layer 3 information using IP address. This allows the network to go across different Protocols. Routers also serve as the first line security that protecting the network from any attack and intrusion.

Working to route the packets to their destination, a router analyzes the layer 3 destination address of every packet, and decides the best next hop for it. This process takes time, and hence every packet encounters some delay because of this.

The basic features of layer 3 switch vs router are listed below:. A layer 3 switch is both a switch and a router: it can be regarded as a router with multiple Ethernet ports and with switching function. The advantages of connection, etc. In addition, in order to connect to various types of networks, routers have very rich interface types, while Layer 3 switches generally only have the same type of LAN interface, which is very simple.

There are obvious differences in data packet switching operations between routers and Layer 3 switches. Routers are generally based on network processors or multi-core routing engines to perform data packet switching. And the three-layer switch performs data packet switching through hardware. After the Layer 3 switch performs a routing lookup on the first data packet sent to the control plane, it will generate a MAC address and IP address mapping table for the data plane to look up.

When the same data flow passes through again, it will use this table. The routing lookup of the three-layer switch is for data flow. It uses cache technology and is easy to implement with ASIC technology.

Therefore, it can greatly save costs and achieve fast forwarding. Layer 2 switches are used in small local area networks. In a small local area network, the broadcast packet has little effect. The fast switching function, multiple access ports and low cost of the second-tier switch provide a very complete solution for small network users.

Improve Article. Like Article. Last Updated : 23 Sep, Next Difference between Router and Switch. Recommended Articles. Article Contributed By :. Learner asked a question. What's the difference between layer 3 switches and routers? What are things that layer 3 switches can do but routers can't?

Or things that routers can but layer 3 switches can't? There is no difference I can be corrected if I'm wrong. Yes, they do, but not necessarily all the features of routers. I saw Catalyst series switches that were carrying out function of BGP route reflectors in the network, but at the same time running L2 switching as well.

So, it is a switch, but it carries router functions as well. That is one reason I often refer to them as just L2 devices and L3 devices.

We might have business reasons or technical reasons to implement L3 Switches. Too much information, but this is the big picture. You have to dig more. This is especially important when going from higher speed links to lower speed links and vice-versa.

I need to do more research to verify. This is still an interesting question and lets got to extremes to look at it. Routers process packets L3 and switches process frames L2. So at the heart of the Interweb you will find huge router clusters focused on passing packets, maintaining routing table and key services like DNS and security. Increasingly Ethernet is the currency of the Internet core but its a L2 technology right?

Irrelevant, all transport technologies are L2 by definition, so that's not a valid way to define a Switch or a Router. Now there is a good chance that linking these core Interweb Routers you will find a mesh of L2 optical devices, this is the real growth area in networking at the moment.

So here at the very top end we have a separation of services, core switching and core routing are separate. Now lets look at the other extreme, a Mom and Pop outfit, 5 or 6 computers connected to a Switch with a free broadband access router from their ISP, again we have a separation of services, one device for routing and one for switching.

So covering the extremes we hit the middle, where most of us are. We have a network that is too big to be flat, we need to subnet it for scalability, management, efficiency and security.

Now the old way of doing this would be to create VLANs on the Switches and connect them all to a Router and let the Router route packets between the different VLANs but Router interfaces are always more expensive than the equivalent switch interfaces and over time the electronics have become more capable.

So integrate routing functionality into the Switch and let it handle internal IP processing between VLANs, its more efficient and its a lot cheaper because Router interfaces cost more, plus you can make do with smaller and cheaper Routers because they are only processing the WAN load, not the LAN load. Job done, L3 Switches in the Enterprise, with Routers for WAN connections so the first answer to your question would be a Router routes packets over the Wide Area while a L3 Switch routes packets within a campus but this only takes us up to about the Year Moore's law being what it is, electronics and interfaces have got cheaper and the switches have got more capable so effectively now you can buy a medium sized Enterprise Switch which also offers full Enterprise routing functionality, so you don't need a stand alone Router.

Again the L2 technology used is also irrelevant, as Ethernet is used for a lot of WAN now, we have to define by service and function boundaries. It is important to realise that it might be the same device providing both of these functionalities, in which case you could talk about it having both L3 Switching functionality and Routing functionality.