How far does a gratuitous ARP message propagate?

[jmaxwellUSAF]

Please forgive me as my basic understanding has become fuzzy...

In the topology with layer 2 switches...

ROUTER1=====SWITCH1=====SWITCH2=====SWITCH3=====ROUTER2=====SWITCH4

1. If ROUTER1 sends a gratuitous arp message, at what device will the message stop?

2. Is it true that all the devices within this path update their arp tables?

Thank you!

[MHM Cisco World · Accepted solution]

GARP use mac address of FFFF:FFFF:FFFF so it will flood in all SW that share same broadcast domain, and it stop at router boundary. 

[jmaxwellUSAF]

So Router2 updates arp table as well?

If the above switches were level 3 switches, is the result the same?

[MHM Cisco World]

even if it L3SW it still SW and if it share the same broadcast domain then it will flood to all port (port that config with same VLAN). 

[Joseph W. Doherty]

"So Router2 updates arp table as well?"

It should.

"If the above switches were level 3 switches, is the result the same?"

If the L3 switches are carrying the "same" L2 broadcast domain, yes.  (As also described in @MHM Cisco World reply.)

If the L3 switches are L3 hops, no.

BTW, Cisco routers may have the capability to bridge L2 too.  So, even in your first example, if router2 is doing that, switch4 could have its ARP table updated too.

As MHM initially answered, it really depends on the extent of the L2 broadcast domain.