In our office, we have our router that is connected to the internet.  

From there, we would like to lay an ethernet cable to 3 other rooms with about 30 computers.  

We were considering the following setup: 

```
Router --> Ethernet cable (10 meters) --> Switch in Room 1 -->
Ethernet cable (5 meters) --> Switch in Room 2 -->
Ethernet cable (30 meters) --> Switch in Room 3

```

Now my question: Will we have any performance issues due to the fact that all users will share this one single line?  

What kind of ethernet cable would you recommend? Cat7?  

Any other problems we might run into?

*Edit:*  

Internet connection is 50 Mbit down, 10 Mbit up.  

The router is an AVM FRITZ!Box 3490 which supports QoS: <http://www.amazon.de/dp/B00N80INBM>  

Switches and ethernet cables will be bought soon.  

The computers will use the following services:  

 - Regular "surfing"  

 - VOIP  

 - SSH / FTP to external servers  

 - Accessing internal file server