networks: Added simple reusable linear networks for PPP and Wifi.

src/inet/networks/ppp/LinearNetwork.ned

@@ -0,0 +1,27 @@
+//
+// SPDX-License-Identifier: LGPL-3.0-or-later
+//
+
+package inet.networks.ppp;
+
+import inet.networks.base.WiredNetworkBase;
+import inet.node.inet.Router;
+import inet.node.inet.StandardHost;
+
+network LinearNetwork extends WiredNetworkBase
+{
+    submodules:
+        client: StandardHost {
+            @display("p=350,200");
+        }
+        router: Router {
+            @display("p=550,200");
+        }
+        server: StandardHost {
+            @display("p=750,200");
+        }
+    connections:
+        client.pppg++ <--> { datarate = 100Mbps; delay = 1us; } <--> router.pppg++;
+        router.pppg++ <--> { datarate = 100Mbps; delay = 1us; } <--> server.pppg++;
+}
+

src/inet/networks/wifi/LinearNetwork.ned

@@ -0,0 +1,25 @@
+//
+// SPDX-License-Identifier: LGPL-3.0-or-later
+//
+
+
+package inet.networks.wifi;
+
+import inet.networks.base.WirelessNetworkBase;
+import inet.node.contract.INetworkNode;
+import inet.node.wireless.AccessPoint;
+
+network LinearNetwork extends WirelessNetworkBase
+{
+    submodules:
+        client: <default("WirelessHost")> like INetworkNode {
+            @display("p=350,200");
+        }
+        ap: AccessPoint {
+            @display("p=550,200");
+        }
+        server: <default("WirelessHost")> like INetworkNode {
+            @display("p=750,200");
+        }
+}
+