EEE8089 Assignment: Raspberry Pi Network Architecture and Remote Access Configuration

Part 1 of the practical coursework focuses on

• network architecture
• access from home
• design problems to solve
• (Part 2 in a separate lecture)

Three Architectures

Three main architectures are defined:

• Target Architecture—the main design effort
• Instrumental Architecture—pre-configured to provide access to the components of the design
• Access From Home Architecture—a scheme for accessing the above two configurations remotely

Device Configuration

    Four RPi 3B+ devices, replace # with group number,
    multiple names for the devices with several OS images:
    
    ManagerPi#
    MasterRig#2x: MyRig#25, MyRig#26, MyRig#27, MyRig#28
    MasterRig#3x: MyRig#35, MyRig#36, MyRig#37, MyRig#38
    MasterRig#4x: MyRig#45, MyRig#46, MyRig#47, MyRig#48
    Note: the last three are often referred to as RigPi

IP Addresses for Groups

Tasks to Complete

• Find the IP addresses, define the LANs and determine which gateways to use.
• Configure the devices, test them, debug any problems.
• Test the connectivity: each device should be able to talk to any other and to www.
• Use tcpdmp to examine Ethernet, IP and TCP packets, find the key fields in the headers of these packets.
• Examine the latency and throughput of connections within one LAN, between two LANs and between three LANs.
• Generate and distribute SSH keys between the devices, so SSH sessions could be started without typing a password. Experiment with forwarding a data pipeline through SSH between two devices.

Instrumental Architecture

Using the Instrumental Architecture

1. Get SSH access to ManagerPi# by using Access From Home Architecture.
2. From ManagerPi access RigPi devices – they are running in MasterRig mode.
3. Each MasterRig device can be logged in as user pi with provided password.
4. The OS images of MyRig (four spares per device) are mounted as ~/rootfs5…8.
5. Edit the chosen OS image, then reboot RigPi into this image (MyRig mode) by creating a file ~/boot_5 (or 6,7,8) and then rebooting the device.
6. The next reboot will take you back into the MasterRig mode.

Instrumental Architecture IP Addresses

Hardware Reboot of MyRig

If the network connection to the MyRig fails, then hardware reboot is possible by issuing a command from ManagerPi.

Soft Reboot (for MyRig#2x device)

    echo 0 > /sys/class/gpio/gpio17/value
    echo 1 > /sys/class/gpio/gpio17/value

Hard Reboot (may cause filesystem corruption—try to avoid)

    echo 0 > /sys/class/gpio/gpio27/value
    echo 1 > /sys/class/gpio/gpio27/value

MyRig#2i: soft reboot gpio17, hard reboot gpio27

MyRig#3i: soft reboot gpio22, hard reboot gpio10

MyRig#4i: soft reboot gpio9, hard reboot gpio11

Using from Home

Everywhere below, replace # with your group number.

    
Set up the ssh tunnels to import the ports from unix.ncl.ac.uk
    Group #: 10#22, 10#80
    
Login into ManagerPi#
    ssh -Y -p 10#22 login_name@localhost
   
 View the video feed in the browser (tested with Firefox):
    http://localhost:1080

Answer

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