gateway configuration in this scenario.

router 0 and router 1 are connected in an Ethernet via a switch. And another two hosts are in the same subnet in between. My question is which router should be used as the gateway of the router?

Or, no hosts should be added in the in-between ethernet at all?

gateway.jpg

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Comments

netsysllc

From the limited detail I would say either could be the gateway. Whatever router has the same subnet should work as long as it has routes to the other networks

johnifanx98

netsysllc wrote: »

From the limited detail I would say either could be the gateway. Whatever router has the same subnet should work as long as it has routes to the other networks

Each router has an interface in the same subnet. So, I doubt "either" is the answer...

TurK-FX

johnifanx98 wrote: »

Each router has an interface in the same subnet. So, I doubt "either" is the answer...

I also posted on your other thread. You can use either of the router as default gateway, but when the switch trying to communicate outside, it will only communicate to default gateway router`s side. So there wont be any communication going to other router from either host.

Why do you need to go that kind of network? you can also connect 2 router via crossover cable, and move the switch to one of those router, or removed those hosts, add another switch to one of those routers and move the hosts there.

NetworkVeteran

I also posted on your other thread. You can use either of the router as default gateway, but when the switch trying to communicate outside, it will only communicate to default gateway router`s side. So there wont be any communication going to other router from either host.

Good guess, but this setup will (marginally) work! Suppose Switch is configured with Router0 as its default gateway. When Switch sends a packet towards Router0 intended for PC3, Router0 responds with an ICMP Redirect and tells Switch to use Router1 as the gateway for that destination. Subsequent packets from Switch to PC3 will be sent towards Router1.

TurK-FX

Interesting. I am about to finish my ICND1 study, so i am not expert.
But do you need to configure the router to perform that task? or it is enabled on default?

NetworkVeteran

TurK-FX wrote: »

Interesting. I am about to finish my ICND1 study, so i am not expert.
But do you need to configure the router to perform that task? or it is enabled on default?

ICMP redirects are enabled by default. You may disable them with interface configuration command, "no ip redirects". In the OP's topology, if Switch used R1 as its default gateway, redirects would only be necessary when sending packets to one specific host, PC0.

This would be an acceptable kludge in most cases.

When Are ICMP Redirects Sent? - Cisco Systems

DANMOH009

So if pc4 wanted to send a message to pc test1, will another redirect have to be sent out??

Does this mean that with this design you may need a redirect every time you change direction??

MrBrian

Wow, was not familiar with icmp redirects. Thanks NetworkVeteran, good info