How does a router work with an L2 broadcast request?

Question

System administration

Good afternoon!

I assembled two network models from two PCs and one router in Cisco packet tracer. The PCs are on the same network.

Network diagram:



Task: send a Ping request from 192.168.1.2 to 192.168.1.3.

I don't understand why in the case of one router (Cisco 829) the ping works and the other does not - Cisco 2911.

As I understand the process: I send a ping from PC 192.168.1.2 to 192.168.1.3.
A broadcast arp request is generated, where the poppy is the recipient (FF:FF:FF:FF:FF).
The router receives it and immediately discards it, since the router should not work with L2 broadcast requests.

The router, on the other hand, must drop any frames where a poppy address is specified that is different from its own.

Why does a ping go through the Cisco 829 router? In the books they write that routers limit broadcast requests. A switch must be used to transmit a packet within the same network.

It turns out that some routers can also act as a switch and not discard broadcast frames? Or do all routers do this, but for this you need to enable some kind of function?

Answer 1

> since the router should not work with L2 broadcast requests, the
router should not work with any L2 requests, this is the work of the switch. The router only works on L3. another thing is that something in the router should still be able to work at the L2 level, and this is the router's switching matrix. A router is always also a switch to some extent.
> The router should drop any frames where the poppy address is specified, which is different from its own.
in this case, two devices connected to two different ports on the router and having IP addresses from the same subnet could not communicate with each other.
> Why does the ping pass through the Cisco 829 router?
because that's how he's set up. the corresponding ports are bridged, or there is no prohibition in the firewall, or for some other reason.

Answer 2

My 5 cents.
The router will behave as you configure it. If you want - as a router with each individual port, if you want as a switch - you drive the ports into one bridge