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I am reading the wikipedia article of mac addresses and it states that the least significant bit of the most significant byte of the mac address of a NIC indicates the following:
If the least significant bit of the most significant octet of an address is set to 0 (zero), the frame is meant to reach only one receiving NIC.[5] This type of transmission is called unicast. A unicast frame is transmitted to all nodes within the collision domain, which typically ends at the nearest network switch or router.
I have two computers each has a mac address where the least significant bit of the most significant byte is 0. That means when a frame is sent from the NIC over the ethernet line it is intended to be sent to one receiving NIC. Now I have both my computers wired to a Belkin router. A router avoids collision domain because each NIC has its own dedicated ethernet line. So what kind of collision domain is this article talking about?
If a NIC on one computer sends ethernet data destined to another computer, since both machines are connected to the router, the frame first goes through the router, and then the router keeps some kind of mapping of mac addresses, so it knows which mac address to send to. THat's how I thought it worked. Now you are saying that the router sends a broadcast to all machines connected to it to find out which computer to send the packet to? – JohnMerlino – 2014-03-31T03:00:50.887
Yes, the language is quite badly used in the area. – vonbrand – 2014-03-31T03:01:27.530
@JohnMerlino, the router keeps a table (ARP table) mapping IP addresses to MAC addresses, and uses this to direct traffic. – vonbrand – 2014-03-31T03:02:29.710
1switches propagate L2 broadcasts (like DHCP and ARP requests), but have micro-segmented collision domains, so the two terms are not entirely synonymous. you use switches to break up collision domains, and VLANS/Routers to break up broadcast domains. – Frank Thomas – 2014-03-31T03:06:19.013