Switches and Routers Oh My!

[drows89]

I have a basic understanding of network devices. Switches operate on layer two of the osi model using a mac address table and routers operate on layer three using an ip table. What I fail to understand is when a local or home network connected to the internet would incorporate a switch? Also can a switch share the modem's connection to the web amongst devices on the local connection?

 

[allennnn]

just think of the switch as an extention for the router ports invisible to the router and everything plugged in gets power and just works.

 

[bill001g]

Most switches are using in a home network because their are not enough router ports or they are not located in the correct rooms.

First be very sure you understand what a modem is, a true modem has no concept of IP just like a switch. Its only purpose is to bridge from one media type to another. Very technically you can put switch directly behind a modem and it can be made to work in most cases. A cable modem is one that is easier that some others. Now just because the technology allows it does not mean it will work. The ISP has a limited number of IP addresses and if you ran this way every device would need a actually internet routable IP. So the ISP configure the equipment so you can only have a single device active behind the modem. This is the difference between what the theory says works and what works in the real world.