I just had a very fundamental question about the transition between the router and the switch: I want to know about what happens when a router receives a packet, how does it go about passing it down to the switch to make sure that it arrives at the correct device on that local network?

To my understanding, routers are not MAC aware, and switches are not IP aware. Does the router just send the data out on the broadcast MAC of FF-FF-FF-FF-FF-FF, does it maintain an IP to MAC table, or does it have a smarter way of doing this?

1 Answer 1


On a LAN, a router is simply another host. It passes packets to other hosts in the same LAN the same way that hosts on a LAN pass packets to other hosts on the same LAN.

Routers on a LAN that uses MAC addresses (not all layer-2 protocols use MAC addresses) will use ARP in the same way that hosts on a LAN use ARP to resolve the layer-3 address to a layer-2 (LAN) address.

Unfortunately, the cheapest SOHO devices are explicitly off-topic here. A manufacturer of a hardware device must offer optional, paid support for a device to be on-topic here. See What topics can I ask about here?, especially the caveat under "and meets the following requirements:" hardware that has a paid support option (enterprise/provider class products, some small business class devices).

Questions about consumer-grade devices can be asked on Super User.

  • That was exactly what I was looking for, I now see that the last part was irrelevant. Thanks!
    – Evan Ross
    Aug 6, 2017 at 5:46

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