2651 - T1 to ethernet

[craigshaynak]

I am a programmer by trade so I apologize in advance. Our company has two point to point T1's connecting our two offices via two Cisco 2651 XM routers. We are going to get rid of the second office and I wondered, if we put the two routers in the same room, could I connect the routers via some kind of crossover cable and keep it managing the various subnets? I know, it's dumb.... help!

[Richard Burts]

Craig

These forums have much to offer, both to those with experience and to those who are very new at it. So welcome to the forum.

The real answers about whether you can keep them connected, and if so how to do it, will depend on knowing a bit more about the routers and your environment (what kind of interfaces, what kind of functionality do you currently have and what will you have when these changes are made, where is your outside connectivity provided now and where will it be after the changes) but in general yes you should be able to keep the routers connected and managing the various subnets.

If you can tell us a bit more about what you currently have (what interfaces do you have, what is connected to what interface, what will you need to have after the changes) and what you will need after the changes, then perhaps we can give you better advice about what and how to do.

HTH

Rick

[craigshaynak]

Thanks for the welcome. We have two main Win2K servers connected by two point to point T1's by a CISCO 2651 router on each side. If i were to move both servers in one building, can I maintain my subnetting structure (we really only use two main subnets, each with a 255.255.255.0 mask) so our main server on subnet 1 is simply 192.168.0.9 and the other main server has been assigned 192.168.1.9. Do I even need the routers anymore? If I plug both servers into the switch, can't i maintain these addreses? Thanks for your time and expertise!

[m.christian]

If you have an unused enternet interface, you could assign that to your new subnet.

Or, if you have two routers with T1 WICs you could use a T1 crossover cable. Cross 1 with 4 and 2 with 5.

[craigshaynak]

Thanks for the idea! My question is, do I even need the routers anymore? If I plug both servers into the switch, can't i maintain these addreses using one or both of the servers to hold the routing tables? Thanks for your help in advance!

[griffijo]

My thinking here is why would you limit yourself to 1.5mbps of throughput going across a T1 crossover?The better option is definitely using 2 or more ethernet interfaces on a router, or using a layer 3 switch. You may already have a switch(s) in your network that are capable of doing the same thing a router can do.

[craigshaynak]

Aha! Thanks for the info. We do indeed have a switch as part of our network. I just am unclear as to which machine is in charge of maintaining the routing table. Can I maintain my subnetting structure (we really only use two main subnets, each with a 255.255.255.0 mask) so our main server on subnet 1 is simply 192.168.0.9 and the other main server has been assigned 192.168.1.9. If I plug both servers into the switch, can i maintain these addreses? Thank you so much!

[Richard Burts]

Craig

To answer your question about whether you still need the routers depends on several things. First do you need connectivity to outside resources (especially to the Internet)? If the answer is yes you most likely will need the router(s).

Beyond that consideration is the question of how things are currently configured. On the main server with 192.168.0.9 what mask is configured and what default gateway? Based on your description I am going to guess that the mask on the server is 255.255.255.0. If that is true then plugging both servers into the switch will not work. The server at 192.168.0.9 will believe that the server at 192.168.1.9 is a "remote" destination and will not forward to it but will want to use its default gateway.

So I believe that basically if you want to keep the current subnet structure that you will need to keep the router(s). If you want to change the subnetting structure, it should be quite possible and you could probably eliminate the router(s). But to keep the current structure will likely require keeping the router(s)

HTH

Rick

[craigshaynak]

Thanks! That sounds like the answer. The masks for both servers are set at 255.255.255.0, as you speculated. I guess that means we will keep one router for the local network and keep the hub for one subnet (192.168.0.xxx) plugged into the ethernet port and then plug the hub for the other subnet (192.168.1.xxx) into the second ethernet port on the router. We have another router which connects us to the outside world (internet) which is on the hub connected to one subnet and shared for use with the other subnet. Whew. I am assuming we can configure the second ethernet port on the local router to accept the servers and hosts from the second subnet.