About router

Nowadays even general people use the word “router” as usual, and there is at least one router in every house.

Of course, network engineer or server engineer use the router often, and they have to understand the role of router deeply.

Firstly I didn’t understand “the difference between router and switch” or “the role of router”, so I’ll summarize to deepen my understanding.


Router is basically used to transfer data from network to different network on network layer.

 Router decide which packet to pass through with checking the IP address on the header.


There are mainly 2 types of how to decide the route, “static routing” and “dynamic routing”.

Static Routing: the way to decide the route with checking the routing or ACL which is configured on computer

Dynamic Routing: the way to decide the route automatically based on the rule like RIP, EIGRP, OSPF, etc.


For example, if you use the cisco router, you can see the routing table by typing “show ip route” on command input screen.

Difference from L2SW

So what’s the difference between router and L2SW?


Firstly the layer each device work on is different, router work on layer 3 on the other hand L2SW work on layer 2.

Moreover although I said that router check the IP address on packet header, L2SW check the header of segment and check the MAC address, not IP address.


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