Switch or Router

Routers and Switches.

You want to get into the seven layers of the OSI Model to get a grasp of the difference between routers and switches. In a class the OSI Model is one of the first things taught about networking.

Switches operate at the Layer2 or Datlink:
http://www2.rad.com/networks/1994/osi/datalink.htm

Routers operate at the Layer3 or Network:
http://www2.rad.com/networks/1994/osi/network.htm

If you Search for "OSI Model" you should find a TON of resources to review.

Hope it helps,
Jim

Ok, this I knew. I should have included only lame terms.
What I really want to know, or commented on, is a statement that I heard but am not sure of;
The main difference is that a switch relay traffic without bandwidth loss where a router does.This due to that they operate at the different layers?
/Heinz

Point value changed by question poster.

Ok. Well, you could say that in common situations where a router is used as an IP gateway and all devices share a layer2 switching environment that the switch delivers each device it's own bandwidth where the router would/could be the bottleneck because all are sharing that single point out.

I would disagree that this is the "main" difference as you say in your comment. The switches? job is to separate collision domains. Each port is a collision domain and can provide a ?collision? free layer2 environment for each device connected. Unless of course you put a hub, with multiple machines, on a port then all the machines in the hub is one collision domain.

Routers are used to separate broadcast domains. Switches do not care what broadcast domain you are in; they forward packets based on multicast or unicast.

Let?s examine the scenario using the comment that says ?The main difference is that a switch relay traffic without bandwidth loss where a router does?. What if I have a router with multiple Ethernet interfaces. Commonly, each Ethernet interface would separate a broadcast domain and then connect to a switch or switches with multiple devices. What if I decided to put one computer on each interface? This would be perfectly possible, of course each computer would not only have its? own IP address but also have its? own subnet; provided we were not enabling some bridging techniques. (255.255.255.252 would work fine). This setup would put a router right there where it is delivering a single uplink port to each Computer and making the statement false.

Hope it helped a little.
-Jim

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