Captain Ned wrote:
You only have to route if you're leaving the subnet (going to the Internet) - dumb switches route between machines on the same subnet without having to hit the router.
I knew there was a simple answer my aging brain just hadn't figured out. Like I said, I don't grok the OSI model, so I was having problems figuring out why a device without an IP address could accomplish this.
I know enough about networking to look at a diagram (in the day job) and ask "please explain that decision" (us regulators love open-ended questions). Isn't a whelk's chance in a supernova I'll ever get any networking certs.
I'm sorry but that's not accurate. "Dumb" switches do switching not routing. If the destination MAC is in their address table they send the packet to those port(s). They will never see, nor care about IP addresses.
Now the subnet still matters because if the computer doesn't have a direct route to the device it's destination will be your default gateway (router), but there are various tricks you could do to avoid hitting the slow router interface like putting one of the hosts in two subnets.
Sorry for not using the exactly correct word (I should have said pass instead of route).
I understand how MACs work, but not many consumers really care how switching/routing is done, only what the effects are locally and how it affects them.
For 99.99999% of consumer home networks, there's a subnet for local and then there's everything else - so I was attempting, poorly, to put it into layman's terms.
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