Tutorial 2 - Wireless Network

Overview

This tutorial will cover the use of a 3 node scenario in CORE. Then running a chat server on one node and a chat client on the other. The client will send a simple message and the server will log receipt of the message.

Files

Below is the list of files used for this tutorial.

scenario.xml - 3 node CORE xml scenario file (wireless)
scenario.py - 3 node CORE gRPC python script (wireless)

Running with the XML Scenario File

This section will cover running this sample tutorial using the XML scenario file, leveraging an NS2 mobility file.

Make sure the core-daemon is running a terminal
```
sudo core-daemon
```
In another terminal run the GUI
```
core-gui
```
In the GUI menu bar select File->Open...
Navigate to and select this tutorials scenario.xml file
You can now click play to start the session
Note that OSPF routing protocol is included in the scenario to provide routes to other nodes, as they are discovered

Double click node n4 to open a terminal and ping node n2

ping  -c 2 10.0.0.2
PING 10.0.0.2 (10.0.0.2) 56(84) bytes of data.
64 bytes from 10.0.0.2: icmp_seq=1 ttl=63 time=20.2 ms
64 bytes from 10.0.0.2: icmp_seq=2 ttl=63 time=20.2 ms

--- 10.0.0.2 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1000ms
rtt min/avg/max/mdev = 20.168/20.173/20.178/0.005 ms

Configuring Delay

Right click on the wlan1 node and select WLAN Config, then set delay to 500000

Using the open terminal for node n4, ping n2 again, expect about 2 seconds delay

ping -c 5 10.0.0.2
64 bytes from 10.0.0.2: icmp_seq=1 ttl=63 time=2001 ms
64 bytes from 10.0.0.2: icmp_seq=2 ttl=63 time=2000 ms
64 bytes from 10.0.0.2: icmp_seq=3 ttl=63 time=2000 ms
64 bytes from 10.0.0.2: icmp_seq=4 ttl=63 time=2000 ms
64 bytes from 10.0.0.2: icmp_seq=5 ttl=63 time=2000 ms

--- 10.0.0.2 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4024ms
rtt min/avg/max/mdev = 2000.176/2000.438/2001.166/0.376 ms, pipe 2

Configure Loss

Right click on the wlan1 node and select WLAN Config, set delay back to 5000 and loss to 10

Using the open terminal for node n4, ping n2 again, expect to notice considerable loss

ping  -c 10 10.0.0.2
PING 10.0.0.2 (10.0.0.2) 56(84) bytes of data.
64 bytes from 10.0.0.2: icmp_seq=1 ttl=63 time=20.4 ms
64 bytes from 10.0.0.2: icmp_seq=2 ttl=63 time=20.5 ms
64 bytes from 10.0.0.2: icmp_seq=3 ttl=63 time=20.2 ms
64 bytes from 10.0.0.2: icmp_seq=4 ttl=63 time=20.8 ms
64 bytes from 10.0.0.2: icmp_seq=5 ttl=63 time=21.9 ms
64 bytes from 10.0.0.2: icmp_seq=8 ttl=63 time=22.7 ms
64 bytes from 10.0.0.2: icmp_seq=9 ttl=63 time=22.4 ms
64 bytes from 10.0.0.2: icmp_seq=10 ttl=63 time=20.3 ms

--- 10.0.0.2 ping statistics ---
10 packets transmitted, 8 received, 20% packet loss, time 9064ms
rtt min/avg/max/mdev = 20.188/21.143/22.717/0.967 ms

Make sure to set loss back to 0 when done

Running with the gRPC Python Script

This section will cover running this sample tutorial using the gRPC python script and providing mobility over the gRPC interface.

Make sure the core-daemon is running a terminal
```
sudo core-daemon
```
In another terminal run the GUI
```
core-gui
```
From another terminal run the scenario.py script
```
/opt/core/venv/bin/python scenario.py
```
In the GUI dialog box select the session and click connect
You will now have joined the already running scenario

Running Software

We will now leverage the installed Chat App software to stand up a server and client within the nodes of our scenario. You can use the bases of the running scenario from either scenario.xml or the scenario.py gRPC script.

In the GUI double click on node n4, this will bring up a terminal for this node

In the n4 terminal, run the server

export PATH=$PATH:/usr/local/bin
chatapp-server

In the GUI double click on node n2, this will bring up a terminal for this node

In the n2 terminal, run the client

export PATH=$PATH:/usr/local/bin
chatapp-client -a 10.0.0.4

This will result in n2 connecting to the server
In the n2 terminal, type a message at the client prompt
```
>>hello world
```

Observe that text typed at client then appears in the terminal of n4

chat server listening on: :9001
[server] 10.0.0.2:53684 joining
[10.0.0.2:53684] hello world