Re: networking

[Dan Ritter <dsr@randomstring.org>]

On Fri, Aug 26, 2016 at 12:43:30PM +0200, Pol Hallen wrote:
> Hi all, I'm helping a friend to create a small network on his office (4
> floors)
> 
> I suggests him to separate each networks:
> 
> floor1 - 192.168.1.0/24
> floor2 - 192.168.2.0/24
> floor3 - 192.168.3.0/24
> floor4 - 192.168.4.0/24
> 
> DSL <--> SERVER <--> WAN - 192.168.10.0/24
> 		     NIC1 - 192.168.1.0/24 <--> switch
> 		     NIC2 - 192.168.2.0/24 <--> switch
> 		     NIC3 - 192.168.3.0/24 <--> switch
> 		     NIC4 - 192.168.4.0/24 <--> switch
> 
> what is better? A linux server with 5 NICS (for all floors) or a dedicated
> and cheapest router with 5 NICS? (DSL <--> SERVER <--> ROUTER)

You have several choices.

1. Use a switch for each floor, connect them individually to a
router. All cross-floor communication will need to pass through
the router. This is good for control - you can do firewall
functions between floors as well as to the outside.

2. Use a single switch for all floors, in which case all your
cables need to go to it. This may be a wiring problem. You can
then connect a router to that for Internet access.

3. Use a switch for each floor and connect them to a master
switch next to your router. If the router dies, you still have
cross-floor networking.

4. Use a multi-chassis switch, with one body per floor,
connecting them across floors with suitable cabling. This is
like a hybrid of (2) and (3), offering a lower cost than a giant
switch but the same single management point.

5. Use a switch for each floor, use a router for each floor,
have multiple connections to your central router. (And note that
many mid-to-high end switches have some routing capabilities.)
This can give you resiliency against cable breaks, and local
control as well.

-dsr-