Routing

Kelvin Wang

Hi hope someone can clarify my doubt. Thanks

Scenario 1:

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2 PCs (HostA and HostB) both are connected to a switch and the switch is connected to a router.

Assuming there is only 1 VLAN, if both the hosts are set to different subnets (example: 10.0.1.10 and 10.0.2.20), what configurations are needed on the router/switch to enable the 2 host to communicate?


Scenario 2:

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Same as Scenario 1, but now the host are in separate VLANs. (example: HostA is in VLAN 1 and HostB is in VLAN 2.)

I believe on the switch, trunk port is needed.

What configurations are needed on the router/switch to enable the 2 host to communicate?

networker050184

Kelvin Wang wrote: »

Hi hope someone can clarify my doubt. Thanks

Scenario 1:

---

2 PCs (HostA and HostB) both are connected to a switch and the switch is connected to a router.

Assuming there is only 1 VLAN, if both the hosts are set to different subnets (example: 10.0.1.10 and 10.0.2.20), what configurations are needed on the router/switch to enable the 2 host to communicate?

The first thing that pops into my mind is secondary IPs on the router. Keep in mind this isn't a best practice, especially for the CCNA exams.

Kelvin Wang wrote: »

Scenario 2:

---

Same as Scenario 1, but now the host are in separate VLANs. (example: HostA is in VLAN 1 and HostB is in VLAN 2.)

I believe on the switch, trunk port is needed.

What configurations are needed on the router/switch to enable the 2 host to communicate?

You are going down the right path. A trunk to the router and interfaces for the VLANs. Look into router on a stick.

Kelvin Wang

Thanks. Anyone able to provide a more detailed explanation on what is to be done on the router for both cases?

Netwurk

You're asking very basic routing questions. Get some real hands on if you can. The router-on-a-stick option is cool if your Cisco router only has one hardware interface. But you really need to have at least 2 interfaces to understand routing IMO.

Most 2500's have 2 serial interfaces and buying a pair plus the cables won't cost you much.

And a textbook (or Cisco site research) might help.

Kelvin Wang

networker050184 wrote: »

The first thing that pops into my mind is secondary IPs on the router. Keep in mind this isn't a best practice, especially for the CCNA exams.



You are going down the right path. A trunk to the router and interfaces for the VLANs. Look into router on a stick.

Hi, do you mean configuration sub-interfaces on the router for the 1st scenarios?

mikej412

Kelvin Wang wrote: »

Hi, do you mean configuration sub-interfaces on the router for the 1st scenarios?

networker050184's router on a stick response was for scenario 2.

You got the trunk part on the switch right. On the router side you configure sub-interfaces and encapsulation/vlans.


And the first scenario does sound like a secondary ip address configured on the router interface would work -- and that was a lab from some of the old 640-801 CCNA books.

edit: secondary is an option you to can add to the ip address command. You'd enter your primary interface address with the ip address command. Then you create your secondary address with another ip address command on the interface with the secondary keyword at the end.