Can't find simple router to connect two subnets...

[Steve-O]

Hello board. It's been some time since I've been in, but necessity drives me here and frustration is close behind. I teach Personal Computer Repair for a community college and have been asked to develop an advanced class. In the advanced class I have proposed to set up a small network with two subnets connected by a router. There are seven stations in the classroom, with one desktop PC at each station. I wanted to connect four PCs on one side of the room to three PCs and the instructor PC on the other side of the room. Each PC has an integrated LAN controller on the motherboard. I wanted four PCs on one subnet to connect to a hub, and the uplink of the hub to connect to one interface on the router. From the other side of the room, I wanted the other four PCs on the other subnet to connect to the hub, and the uplink of the hub to connect to the other interface on the router. That's the physical topology of the network. I wanted to use static IP addressing for each PC with a class C IP address and the standard subnet mask. Each interface on the router would be configured as the default gateway for that subnet, receiving the first IP address for the subnet (ex. 193.160.10.1 and 193.160.11.1). The A+ Certification textbook we are using in the basic class shows this EXACT configuration. Also my Network + Certification textbook has the same EXACT configuration in it. So why can't I find a simple router with two interfaces that can both be configured as default gateways to access each remote subnet??? Am I overlooking the obvious? Is this just theoretical and have no practical application? I wanted to use each of these devices/methods (static IPs, hubs, dual interface router) in order to have more things for the students to configure and more places in which to insert troubles for lab. As I'm in the development contract for this advanced class this week and next week, I need to get this worked out pronto, as I need to have the proposal submitted to "the powers that be" by next Friday. Please help with suggestions about what kind, brand, model, etc. of router would allow this application. BTW, there is no WAN access and this will simply be a LAN application, but I still need TWO default gateways to get from one subnet to the other, hopefully in the same router. Thanks in advance for any assistance you might be able to offer...

[ErikD]

You won't find something simple and cheap because it is not a typical simple configuration.

I don't really get how creating a LAN with two different subnets would help teach PC repair, that is more networking related. BTW, you do realize that 193.160.10.1 is a public IP address and is already in use, right? Anyway I have never seen a setup as you describe outside of a corporate environment (or my house ).

If you are set on doing this it can be done easy enough. You would need a router that basically lets you do whatever you want in terms of configuration. I am familiar with Cisco equipment, so will list some examples using them. For a router you get an integrated services platform (2800 series), and any number and type of extra interfaces you desire. The base model includes 2 FastEthernet ports and a number of slots for expansion in which you can add a number of different cards. For your proposed setup (two subnets) the base should do fine. Set an IP address of 192.168.1.1 on f0/0, and 192.168.2.1 on f0/1. Set PCs to use those IPs as gateways as desired.

[Steve-O]

Erik, first of all, thanks for your reply. I was wondering if anyone was going to reply, after a high number of reads and no responses. Now for your questions/comments. I know it's not typical, it's a lab situation. The more that home networking comes into the mainstream, the more these students will be called on to troubleshoot situations in a networking environment. If they have more than a textbook diagram to go by, they will be better equipped to deal with a number of different situations. Yes, I do realize that 193.160.10.1 is a public address. But I also mentioned that there is no exposure to any WAN and that this network will not exist outside the lab. I'm sure this network doesn't exist outside a corporate environment (or your house) , the sole purpose of its existence is academic.

Don't think I'm complaining or resentful of your remarks. I'm really quite grateful that you took the time to share your knowledge. Your last paragraph was most helpful and I will certainly look into the models you described. The I.T. guy at the college was less helpful, and only offered that it would indeed be expensive.

Here's another thought. To circumvent the expense issue, I wonder if the following setup would work? Two residential gateway routers with the WAN ports configured with the IPs you mentioned, and those same WAN ports connected back to back? If that would work, it would be much less costly. Let me know what you think, and thanks again for taking time to assist.

[ErikD]

I was going to say I didn't think it would work. But as I am thinking about it there is a chance it just might. You can assign a static IP address to each WAN interface, and point to the other one as the default gateway. They are directly connected so the route should be learned as they have an interface in that network.

I still don't really see how it would help as a learning experience for computer repair students. My understanding is that they will most likely be working on home computers and such. That is why I say you might just be better off getting real world experience by using a few different models of consumer router, setting them up, configuring, troubleshooting, etc. Giving an example network that is not likely to ever be seen in the real world they will work in is probably more valuable. BUt I don't know what your goals are.