Topology

Building and arranging a topology

Help index · Project overview

Create your first lab

A fresh data directory starts empty. Upload suitable router and switch images, then choose Create a starter topology, or add devices yourself. The built-in starter uses installed images; the starter JSON uses explicit filenames that you may need to adjust.

1. Drag a device from the palette onto the canvas, or click its palette item.
2. Select it, choose an image and resource settings in Inspector, then Apply settings. See device profiles for port conventions.
3. Choose Connect, select two nodes, then choose an unused interface at each end. Each physical interface can belong to only one cable.
4. Click Start lab, or start individual nodes in the inspector. A PC starts after its connected router/switch.
5. Click a running node to open its console. Running means the process started, not that the guest finished booting.

Configure guest interfaces normally and save before stopping. The starter exercise walks through a router, switch and PC. The OSPF exercise provides a routing baseline.

Editing and saving

Topology names and node positions save automatically. Nodes, images, interface allocations and cables require the whole lab to be stopped before structural changes. Node names and positions remain editable while running.

A stopped PC's IPv4 address/prefix and gateway can be edited even while other nodes run. Those values are applied each time that PC starts. A PC has one eth0 interface; increasing its displayed resource values does not add more ports.

Several cables between the same pair of nodes fan out into separate curves. To add another, select the same pair in Connect mode and choose unused ports. While stopped, clicking a cable opens a deletion confirmation. While running, it opens link fault controls. Device deletion also asks for confirmation and reports its attached cables.

Use Import/Export to move between labs. One topology is active per data directory. JSON imports keep matching saved node storage; ZIP restores replace the full node-storage tree.

Panels, zoom and fullscreen

Devices and Inspector show/hide the side panels. Wide-screen choices are remembered in this browser. In portrait view or at widths of 1000px or less, both panels start closed and open one at a time as drawers. Close a drawer with its arrow, Escape, or a tap outside it. Opening a console closes the drawer.

The map supports 20–200% zoom. Use − / +, click the percentage to reset to 100%, or choose Fit to frame the topology. Ctrl+wheel (⌘+wheel on macOS) zooms around the pointer. Drag empty canvas space to pan; ordinary scrolling scrolls the map. Zoom and pan do not change saved node coordinates or console text size.

Names and interface labels remain readable when zoomed out. Device-type labels hide below 75% zoom. Label spacing adjusts around nodes and crowded labels may use a short guide line to their cable.

Fullscreen, beside the zoom controls, expands the entire workspace, including consoles and instructions. Escape or browser Back can leave fullscreen. Unsupported browsers show a disabled button. Mobile layouts adapt to the visible viewport when the software keyboard opens; behavior still depends on the browser.

Float the topology

Float map moves the live topology into a movable, resizable window. Dock returns it to the workspace; Hide (−) keeps its state. Reopen it using Show topology window or Map in a console's Actions menu.

The title and controls share one horizontally scrolling toolbar. Move and Hide stay fixed at the edges. Devices/Inspector buttons are hidden while floating. Dragging the title/grip moves the window; dragging the corner resizes it. These handles support keyboard arrows, with Shift for larger steps. Maximize fills the visible viewport; Restore returns to its previous size.

Clicking a node respects the chosen console layout. Individual floating consoles open without also floating the shared panel. Grouped tabs stay together. Explicit docking remains respected.

Arrange windows

Arrange windows on the map or Arrange in a console tiles the topology, visible console windows and visible instructions across the viewport. A visible docked console panel floats as a group; detach its tabs first to get one tile per console. Hidden consoles stay hidden, and Arrange brings the topology back.

Arrangement restores maximized windows, fits the map to its tile and refits terminals. If the viewport cannot hold the minimum window sizes, it cascades bounded windows instead of creating unusably small tiles. Bring a covered window forward using its tab/node or the Map/Instructions controls. Font settings, connections and input locks survive layout changes.

Swipe horizontally or scroll the mouse wheel over any toolbar to reach controls in a narrow window. Dropdowns retain their own vertical scrolling. Window positions belong to this browser page and reset on reload; they are not saved in lab exports.