Help understanding routers

[Quad]

i'm just a little confused on the main differences between a router and switch.
sure i've read the definition of each, and the forum faqs, but its still not clear.

for example, say we had 2 small networks. they say that you would need a router to connect both networks together. so the router decides the destination of each packet and finds the best way to get it there. but doesn't a switch do that also? doesn't it find the destination based on the mac address of the recipient? so basically, how do they differ?

thx for clarifying. this has been buggin me for a while

 

[JackMDS]

Switch ? Allows communication between Computers on the same Local Network (LAN).

Router - A device which moves network data from one segment of a network to another. Routers are also responsible for determining where data needs to go in order to reach its destination.

Router organizes communication between LANs, that are on the same Wide Area Network.(WAN).

Your private network LAN.

Internet, and you Network WAN.

Hubs, routers, switches, DSL, LANs, WANs...?

 

[Santa]

Please correct me if I missed anything in this.

Just because you know a machine's MAC address does not mean you can route to it.

Routers work on a Network Layer whereas the Switch devices work on the Data Link Layer.

A Switch or Intellegent Hub can not translates logical network address and names to their physical address (e.g. computername ==> MAC address).

Good analogy is think of Routers and Network Layer as what Stamps the destination on a Rail Road Car.. then the Tracks which is the Switch and Data Link Layer work together with this information to get it where it needs to go either to a final destination PC or another router for a differnt stamp.

 

[Quad]

so say you had 2 subnets to accomodate 400 computers in a lan. would you need a router in between for both subnets to communicate with each other?
would that mean that each subnet would have to use different ip ranges?

 

[ScottMac]

yep. That's correct. Routers (Layer three devices) connect subnets.

Hubs & switches connect computers (sometimes switches are used to aggregate a group of segments, all on the same subnet)

Routers connect the networks and subnets together (and VLANs too - another way to reduce the node count in a broadcast domain).

Routers can't route to the same subnet. Switches can't switch to a different subnets (ignoring NHRP/MPOA).


FWIW

Scott

 

[Quad]

excellent. thx guys for clearing this up. i think i have a better understanding of the difference now

weeee