Migrate-to-the-new-version.md

@@ -48,4 +48,87 @@ More options are available using the JSON network configuration file: check them
 
 ### Python Network Configuration
 
-Beside having the JSON network configuration method, one can start and initialize the network using also the new Python `NetworkAPI`.
\ No newline at end of file
+Beside having the JSON network configuration method, one can start and initialize the network using also the new Python `NetworkAPI`. Hereafter, we provide a simple example of how to use this new method and a comparison with the legacy JSON configuration file. If you need more information and instructions on how to exploit this functionality, please check out the documentation of *P4-Utils*.
+
+```python
+from p4utils.mininetlib.network_API import NetworkAPI
+
+net = NetworkAPI()
+
+# Network general options
+net.setLogLevel('info')
+net.enableCli()
+
+# Network definition
+net.addP4Switch('s1')
+net.setP4CliInput('s1', 's1-commands.txt')
+net.addP4Switch('s2')
+net.setP4CliInput('s2', 's2-commands.txt')
+net.addP4Switch('s3')
+net.setP4CliInput('s3', 's3-commands.txt')
+net.setP4SourceAll('program.p4')
+
+net.addHost('h1')
+net.addHost('h2')
+net.addHost('h3')
+net.addHost('h4')
+
+net.addLink("h1", "s1", weight=5)
+net.setBw('h1', 's1', 20)
+net.setDelay('h1', 's1', 20)
+net.setMaxQueueSize('h1', 's1', 100)
+net.setLoss('h1', 's1', 0.01)
+net.addLink("h2", "s2")
+net.addLink("s1", "s2")
+net.addLink("h3", "s3")
+net.addLink("h4", "s3")
+net.addLink("s1", "s3")
+
+# Assignment strategy
+net.mixed()
+
+# Nodes general options
+net.enablePcapDumpAll()
+net.enableLogAll()
+
+# Start the network
+net.startNetwork()
+```
+
+The Python script shown above is equivalent to the following JSON network configuration file. Indeed, both snippets define the same network topology.
+
+```json
+{
+  "p4_src": "program.p4",
+  "cli": true,
+  "pcap_dump": true,
+  "enable_log": true,
+  "topology": {
+    "assignment_strategy": "mixed",
+    "links": [
+      ["h1", "s1", {"delay":"20ms", "loss": 1, "bw": 20, "max_queue_size": 100, "weight":5}], ["h2", "s2"], ["s1", "s2"], ["h3", "s3"],["h4", "s3"], ["s1", "s3"]
+    ],
+    "hosts": {
+      "h1": {
+      },
+      "h2": {
+      },
+      "h3": {
+      },
+      "h4": {
+      }
+    },
+    "switches": {
+      "s1": {
+        "cli_input": "s1-commands.txt"
+      },
+      "s2": {
+        "cli_input": "s2-commands.txt"
+      },
+      "s3": {
+        "cli_input": "s3-commands.txt"
+      }
+    }
+  }
+}
+```