Routing Subnet – How to Route to Multiple Subnets

routingsubnet

Having a 192.168.1.0/24 network connected to a router1 on eth0, I want to access several others in the 192.168.222.0/28, 192.168.222.16/28, …, 192.168.222.240/28 range, all accessible through eth1.

Is it OK to add a single "192.168.222.0/24 via eth1" routing entry, or do I need to add one for each network "192.168.222.0/28 via eth1", "192.168.222.16/28 via eth1", …

Kind regards.

Edit

Actually, eth1 is connected to another router2, living in the first subnet 192.168.222.0/28 with the IP 192.168.222.1. That one is the one routing to all the other subnets, that is, specifying their gateways with individual rules. So that router2 is the one which would be the gateway for router1's "192.168.222.0/24 via 192.168.222.1%eth1" entry.

On router1 is it possible to insert just one rule? Can there the "route summary" Pedro Brito is talking about be applied?

Best Answer

It's generally possible. It's called a route summary and normally used to simplify routing when using static routes or to reduce the size of the routing table.

If there's a subnet in the range that isn't accessible via eth1, packets are still going to be delivered in that interface, unless there's a more specific route pointing somewhere else.

Related Solutions

Configuring Cisco ASA 5505 for Routing

OK, after looking at your configuration, you are missing one statement:

route outside 0.0.0.0 0.0.0.0 125.x.x.9

This tells the firewall to forward all Internet traffic to the ISP's router at 125.x.x.9

OpenFlow Example – Understanding and Verification

I think you've mostly got it.

There are a few points I would make though.

The path P_0, from R to C_1, is often (but not always) implemented 'out-of-band', as a separate network.
Only one, or a handful, of packets for each network flow should reach C_1. As soon as the flows are inserted by the AmyOSPF controller, they are simply forwarded according to that routing logic. This is what the second quote says.
No. AmyOSPF computes the best path P_1 from R to the destination of the packets, wherever that may be. It can do this without talking to the switches.

The flow entries that make up the path P_1 is then sent to the routers on P_1, so that all traffic coming from Amy's machine to a particular destination are sent along that path, without having to go to the controller. In the case of R, this new flow entry must have higher priority than the one that says to send all traffic from that port to the controller.

It's not really a multicast, the controller has a separate connection to each switch/router. The flow entries may be slightly different for each router too.
The point is that it doesn't matter what 'view' the router has, as all of the routing is done in the controller. But C_0 does have a global view.

This will have to be repeated for each new network flow originating from Amy's machine. It wouldn't make sense to create a path from R to X and then send packets destined for Y along it. Having said that, flow entries can be aggregated.

Best Answer

Related Solutions

Configuring Cisco ASA 5505 for Routing

OpenFlow Example – Understanding and Verification

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