Questions about Multi-hop network topology mgen configuration

[szl0144]

Hi,

I am run a demo with 3 nodes multi-hop network topology in EMANE, I use multicast address 225.1.20.1/5001 as destination in mgen. I have changed the path loss between node1 node2 and node 3 to achieve a topology to let node 1 transmit packet through relay node2 to node3 rather than transmit packet directly to node3. Because mgen sends packets to all of three nodes, but I want to just let mgen send packet to node 1 and node 1 deliver packets to node 3 through node 2. I don't know how to use a unicast address to let mgen send packet to node 1 firstly, and packets are sent to node 3 through node 2 next my topology. Can you give me some ideas?

The following figure may describe my topology clearly.

Thank you very much.

Best, Shaoyi

[weston-nrl]

What you are looking for, regardless of whether you use unicast or multicast, is called routing. There are many types (e.g. static routing, dynamic routing) and methods/algorithms. They can work different ways (e.g. in some cases multiple interfaces are required), I suggest reading up on it.

Edit to clarify: this is easy to do with unicast (send just to 'node3') -- the underlying routing tables at each hop from beginning to end need to know where to send the packet next to get it to its destination. They don't need to know the full path, just the next hop.

[szl0144]

I see, thank you for your suggestion. I just checked the static routing and dynamic routing, I am looking for a static routing from mgen to node 3 through node 1 and node2. Do you mean I need to implement some routing algorithm in EMANE?

[weston-nrl]

No. EMANE emulates wireless links between nodes. What those end systems do with those packets (generation, reception, forwarding/routing) has nothing to do with EMANE. They are done using the exact same methods and protocols/executables that you would use on the real physical system/network without EMANE. The commands are identical whether the interface is an EMANE interface or a real physical interface.

For static routing, you just need to add the appropriate static routes to each node's routing table (e.g. for linux, Google the 'route' and/or 'ip route' commands).

[szl0144]

I see, sorry about some misunderstandings about the IP routing part. I think your explanation of manually routing configuration is clear to me, thank you for your help!