Application Architecture¶

Overview of the CISCO / BushNET Serial Manager application architecture.

Overview¶

The CISCO / BushNET Serial Manager is a Qt6-based GUI application written in C++17. It provides a graphical interface for managing serial console connections to CISCO / BushNET industrial Ethernet switches.

Architecture Diagram¶

┌─────────────────────────────────────────────────────────────────┐
│                         MainWindow                               │
│  ┌─────────────┐  ┌─────────────────┐  ┌─────────────────────┐  │
│  │   Menu Bar   │  │   Toolbar       │  │   Status Bar        │  │
│  └─────────────┘  └─────────────────┘  └─────────────────────┘  │
│  ┌──────────────────────────────────────────────────────────┐   │
│  │                   QTabWidget (Main Tabs)                   │   │
│  │                                                           │   │
│  │  ┌──────────┐ ┌────────────┐ ┌───────────┐ ┌──────────┐ │   │
│  │  │ Welcome  │ │  Terminal  │ │  Switch   │ │   SNMP   │ │   │
│  │  │   Tab    │ │   Widget   │ │  Panel    │ │  Monitor │ │   │
│  │  └──────────┘ └────────────┘ └───────────┘ └──────────┘ │   │
│  │                                                           │   │
│  └──────────────────────────────────────────────────────────┘   │
│  ┌──────────────────────────────────────────────────────────┐   │
│  │                   CredentialsTab                          │   │
│  │       (Auto-login, Password Management)                   │   │
│  └──────────────────────────────────────────────────────────┘   │
└─────────────────────────────────────────────────────────────────┘
          │                    │                    │
          ▼                    ▼                    ▼
┌─────────────────┐  ┌─────────────────┐  ┌─────────────────┐
│  SerialManager  │  │   SnmpClient    │  │   DeviceConfig  │
│  (QSerialPort)  │  │  (QUdpSocket)   │  │   (QSettings)   │
└─────────────────┘  └─────────────────┘  └─────────────────┘
          │                    │
          ▼                    ▼
┌─────────────────┐  ┌─────────────────┐
│   Serial Port   │  │   UDP/SNMP      │
│   /dev/ttyUSB0  │  │   Port 161      │
└─────────────────┘  └─────────────────┘

Key Components¶

MainWindow¶

File: mainwindow.h, mainwindow.cpp

The main application window that orchestrates all UI components and manages the application state.

Responsibilities:

• Main window layout and UI orchestration
• Menu and toolbar management
• Dialog launching and coordination
• Application state management

SerialManager¶

File: serialmanager.h, serialmanager.cpp

Handles all serial port communication with the CISCO / BushNET switch.

Responsibilities:

• Serial port opening/closing
• Data transmission and reception
• Connection state management
• Signal emission for received data

TerminalWidget¶

File: terminalwidget.h, terminalwidget.cpp

A terminal emulator widget with ANSI color support.

Responsibilities:

• Display received serial data
• Parse ANSI escape sequences for colors
• Handle user keyboard input
• Command line editing

CommandHistory¶

File: commandhistory.h, commandhistory.cpp

Manages command history for the terminal.

Responsibilities:

• Store previous commands
• Navigate history (up/down arrow)
• Command persistence

WelcomeTab¶

File: welcometab.h, welcometab.cpp

Welcome landing page displayed when the application starts.

Responsibilities:

• Display product branding and company information
• Show application version and description
• Custom-painted background with Astute Systems branding

CredentialsTab¶

File: credentialstab.h, credentialstab.cpp

Manages switch login credentials with auto-login support.

Responsibilities:

• Store username, password, and enable password
• Remember credentials between sessions
• Auto-login to the switch on connection
• Auto-enter enable mode

SnmpClient¶

File: snmpclient.h, snmpclient.cpp

Pure Qt SNMP client implementing SNMPv1/v2c using BER/ASN.1 encoding over UDP.

Responsibilities:

• SNMP GET, GETNEXT, GETBULK, and WALK operations
• BER/ASN.1 encoding and decoding
• Asynchronous and synchronous operation modes
• Request retry with timeout tracking
• OID-to-name resolution for common MIBs

SnmpMonitorTab¶

File: snmpmonitortab.h, snmpmonitortab.cpp

Real-time SNMP monitoring dashboard with Qt Charts integration.

Responsibilities:

• System information display (hostname, uptime, description)
• CPU utilisation monitoring with time-series charts
• Memory usage tracking with area charts
• Per-interface bandwidth monitoring with line charts
• Environmental monitoring (temperature, PSU, fans)
• Configurable polling intervals

ConnectionDialog¶

File: connectiondialog.h, connectiondialog.cpp

Dialog for configuring serial port connection parameters.

Responsibilities:

• Port selection
• Baud rate configuration
• Data bits, parity, stop bits settings
• Flow control options

SwitchPanelWidget¶

File: switchpanelwidget.h, switchpanelwidget.cpp

Visual representation of the switch front panel.

Responsibilities:

• Display port layout
• Show port status (up/down/disabled)
• Click to configure individual ports
• BushNET connector mapping

DeviceConfig¶

File: deviceconfig.h, deviceconfig.cpp

Handles device profile saving and loading.

Responsibilities:

• Save connection settings
• Load saved profiles
• Configuration file management

Dialog Components¶

Configuration Management¶

Network Management¶

Security¶

SNMP & Monitoring¶

System¶

Data Flow¶

Sending Commands (Serial)¶

User Input → TerminalWidget → MainWindow → SerialManager → QSerialPort → CISCO / BushNET

Receiving Data (Serial)¶

CISCO / BushNET → QSerialPort → SerialManager → (signal) → MainWindow → TerminalWidget

SNMP Monitoring¶

SnmpMonitorTab → SnmpClient → QUdpSocket → UDP Port 161 → CISCO / BushNET
CISCO / BushNET → UDP Response → QUdpSocket → SnmpClient → (signal) → SnmpMonitorTab → Charts

SNMP Configuration (via Serial)¶

SnmpConfigDialog → MainWindow → SerialManager → QSerialPort → CISCO / BushNET

Signal/Slot Connections¶

The application uses Qt's signal/slot mechanism for communication:

// SerialManager signals
void dataReceived(const QByteArray &data);
void connectionStateChanged(bool connected);
void errorOccurred(const QString &error);

// SnmpClient signals
void responseReceived(int requestId, const SnmpResponse &response);
void walkCompleted(int requestId, const QList<SnmpVarbind> &results);
void errorOccurred(int requestId, const QString &errorMessage);

// Example connections in MainWindow
connect(m_serialManager, &SerialManager::dataReceived,
        m_terminalWidget, &TerminalWidget::appendData);

// SnmpMonitorTab connects directly to SnmpClient
connect(m_snmpClient, &SnmpClient::responseReceived,
        this, &SnmpMonitorTab::onResponseReceived);

Configuration Files¶

The application stores settings in:

• Linux: ~/.config/AstuteSystems/IE3300SerialManager.conf

Settings include:

• Last used serial port
• Connection parameters
• Window geometry
• Recent device profiles

Threading Model¶

The application runs on a single thread with Qt's event loop. The QSerialPort class uses asynchronous I/O with signals for data reception. The SnmpClient uses QUdpSocket for asynchronous SNMP communication over UDP. Both avoid the need for separate threads by leveraging Qt's event-driven architecture.

The SnmpMonitorTab uses a QTimer for periodic polling, triggering SNMP requests at configurable intervals. Responses are delivered asynchronously via signals.

Dependencies¶

Build System¶

The project uses CMake with Qt's AUTOMOC, AUTORCC, and AUTOUIC features:

set(CMAKE_AUTOMOC ON)
set(CMAKE_AUTORCC ON)
set(CMAKE_AUTOUIC ON)

This automatically generates:

• MOC files for Q_OBJECT classes
• Resource compilation for .qrc files
• UI class generation for .ui files