Routing on a 2D Torus Topology
Posted on 2000-01-11
Hello. I am currently setting up a 2D Torus network topology with 9 hosts and 1 server. Each host has four network cards on it and the IP addresses are distributed on 19 subnetworks including the server. Each node has a direct connection to 2 adjacent nodes and the nodes on the end of the row and column. Here is a diagram to better describe the topology.
1 --- 2 --- 3 ---
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4 --- 5 --- 6 ---
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7 --- 8 --- 9 ---
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note: diagram might be unaligned. 2 connected with 5, 5 connected to 8, 3 connected with 6, 6 connected with 9 Hope you can make sense of it!
The server is connected to 1. All packets that are sent to any node on the network have to travel through 1. The lines in the diagram represent connections. The lines on the end of the rows coming from 3, 6, and 9 are connected to the nodes on the beginning of the rows(3 connected to 1, 6 connected to 4, and 9 connected to 7). The lines on the end of the nodes on the bottom of the columns are connected to the top of the columns(7 connected to 1, 8 connected to 2, and 9 connected to 3. We have configured our subnets and IP addresses correctly. All nodes that are directly connected to each other can communicate. We have been able to route to a node that is at most 2 hops away from another. The server can ping 2, the server can ping 4, and the server can ping 7. 1 can ping 5 through 4 and 2 can ping 9 through 3. The problem has come when we try to communicate with a node that is 3 hops away. Server to 5. What we want to do is to go from the server to 5 through 1 and 4. The farthest we have been able to get is to be able to ping the interface on 4 that is directly connected to 5 from the server. Now since we can ping, from the server, the interface on 4 that is connected to(on the same network as) 5, we are trying to use that interface as a gateway to 5. When we set it up that way we still cannot communicate with 5 from the server.
Not the problem:
- Subnet IP addresses are configured correctly.
- The route the packet has to take is not a one way street. To get to 5 from the server the gateway is the interface on four that is connceted to five and to get from 5 to the server the gateway is the interface on 1 that is connected to the server.
-The routes are staying in the system upon reboot because they are placed in the static-routes file which is scanned to place routes in the routing table upon reboot.
-We can ping the interface that is connected to 5 on 4 from the server and we can ping the interface on 1 that is connected to the server from 5.
Currently when setting up this network, when we want to communicate with 5 from one, the gateway to five would be the interface on 4 that is connected to five. That method has been working for use successfully for 2 hop communication. The bottom line is: How do we communicate with one node to another when the communication requires more than 2 hops? How do we set up the route and are we configuring the gateways correctly?
P.S. - Will we be able to collaborate on this question without me losing any more points?