A visual, interactive network simulator that teaches real networking concepts — from basic IP forwarding through OSPF, BGP, MPLS, VLANs, VXLANs, ACLs, and beyond. Built in C++17 with raylib.
Under active development. Features are being added rapidly and things may break between commits. Not recommended for production use — but great for poking around.
Packet Path is a scenario-based learning game where you configure real network topologies and watch packets animate through them in real time. Every routing decision, label swap, ARP resolution, and ACL hit is shown visually and logged — so you can see exactly why a packet succeeded or was dropped.
It is not a toy model. The simulation engine runs real protocol behavior: OSPF SPF, BGP path selection, MPLS label distribution via LDP, 802.1Q VLAN tagging, VXLAN + BGP EVPN, stateful ACL evaluation, and NAT. The goal is to build intuition for how these protocols actually work, not just what they're called.
| # | Title | Concepts |
|---|---|---|
| 1 | Basic Ping | IP forwarding, ARP, static routes |
| 2 | Multi-Hop Routing | Default gateway, multi-hop paths |
| 3 | Router-on-a-Stick | Inter-VLAN routing, subinterfaces |
| 4 | VLAN Trunking | 802.1Q, trunk vs access ports, VLAN isolation |
| 5 | OSPF: Single Area | OSPF hello, adjacency FSM, SPF, RIB |
| 6 | Multi-Area OSPF: ABR | Area 0 backbone, ABRs, inter-area routes |
| 7 | iBGP Full Mesh | iBGP sessions, next-hop-self, OSPF underlay |
| 8 | eBGP Peering | AS numbers, eBGP sessions, prefix advertisement |
| 9 | BGP Route Reflection | RR topology, client/non-client, cluster IDs |
| 10 | ACL Firewall | Access control lists, permit/deny rules |
| 11 | VXLAN Overlay | VXLAN encapsulation, VNI, overlay vs underlay |
| 12 | NAT: Internet Access | PAT/overload NAT, address translation |
| 13 | MPLS Label Switching | LDP, label push/swap/pop, LSP |
| 14 | Link Down | Failure detection, OSPF reconvergence |
| 15 | VLAN Gateway Down | Failure isolation, partial connectivity |
| 16 | Dual Failure | Multi-failure troubleshooting |
- Animated packet movement along bezier cable curves
- ARP resolution with request/reply/cache behavior
- Hop-by-hop forwarding with per-device RIB/FIB
- OSPF: hello timers, adjacency state machine (Down → Init → 2-Way → Full), LSDB, Dijkstra SPF
- BGP: eBGP/iBGP sessions, route reflection, path selection
- MPLS/LDP: label distribution, push/swap/pop at each LSR
- 802.1Q: trunk/access ports, VLAN tag handling, frame forwarding
- VXLAN + BGP EVPN: overlay encapsulation, MAC/IP route advertisement
- ACL: ordered permit/deny rules applied per interface/direction
- NAT: PAT/overload translation with connection table
- Infinite pan/zoom canvas (Camera2D)
- Drag-and-drop devices (PC, Router, Switch, PE)
- Click-to-wire bezier cable connections
- Side config panel: IP addresses, routing, OSPF, BGP, ACL, NAT, VLAN per device
- Floating, draggable mission briefing card (collapsible, auto-sizing)
- Packet trace modal: step-by-step hop decisions with MPLS/ACL/NAT annotations
- Log console with mouse-wheel scroll and auto-height
- Star rating (1–3) based on solution efficiency
- Slow-motion replay
- Save/load topology
- Sandbox mode (free play, no objectives)
- Failure injection (link cuts, device crashes)
- Sound effects on key events
- macOS (tested on macOS 13+)
- g++ with C++17 support
- raylib 5.5 installed via Homebrew or system path
brew install raylibgit clone https://github.com/PiMPStudios/packet-path.git
cd packet-path
make
./packet-pathThe Makefile uses pkg-config to find raylib automatically, falling back to /usr/local/include and /usr/local/lib if pkg-config is unavailable.
| Input | Action |
|---|---|
P / R / S |
Spawn PC / Router / Switch |
| Left-click | Select device, drag nodes and cables |
| Right-click | Context menu (send packet, delete, rename) |
| Middle-mouse drag | Pan canvas |
| Scroll wheel | Zoom canvas (canvas area) / scroll log (log area) |
B |
Toggle mission briefing card |
H |
Toggle help overlay |
M |
Return to menu |
ESC |
Close modal / return to menu |
src/
├── main.cpp — game loop, input, state machine
├── SimulationEngine — packet forwarding, protocol dispatch
├── OspfEngine — OSPF hello/LSDB/SPF
├── BgpEngine — eBGP/iBGP/route reflection
├── LdpEngine — MPLS label distribution
├── EvpnEngine — VXLAN/BGP EVPN
├── AclEngine — ACL evaluation
├── NetworkCanvas — canvas rendering, log console
├── ConfigPanel — device configuration UI
├── GameUI — briefing card, overlays, HUD
├── TraceModal — packet trace viewer
├── Level — JSON level loader
├── Device / Cable / Packet — core data structures (no raylib)
├── Font / Layout — shared rendering helpers
└── SoundEngine — audio events
All protocol logic lives in *Engine classes with no raylib dependency. Rendering is isolated to *Canvas, *Panel, *UI, and *Modal files. Data structures (Device, Cable, Packet) are plain C++ structs.
The simulator is built against published RFCs. Key references in docs/RFCs/:
| RFC | Protocol |
|---|---|
| RFC 791 | IPv4 |
| RFC 826 | ARP |
| RFC 2328 / 5340 | OSPFv2 / OSPFv3 |
| RFC 4271 / 4760 | BGP-4 / Multiprotocol BGP |
| RFC 3031 / 3032 | MPLS Architecture / Label Stack |
| RFC 5036 | LDP |
| RFC 7348 | VXLAN |
| RFC 7432 / 8365 / 9135 | BGP EVPN |
| RFC 8402 / 8660 / 8754 | Segment Routing / SRv6 |
| IEEE 802.1Q | VLANs |
The core engine, 16 levels, and all UI features listed above are implemented and working on macOS. Active development continues.
- IPv4 forwarding, ARP, static routes
- OSPF (single-area and multi-area, SPF, adjacency FSM)
- BGP (eBGP, iBGP, route reflection)
- MPLS / LDP (label push/swap/pop, LSP)
- 802.1Q VLANs and trunking
- VXLAN + BGP EVPN
- ACLs and NAT
- RSVP-TE — explicit path computation, bandwidth constraints (in testing)
- Segment Routing — SR-MPLS (SID allocation, label stack) and SRv6
- IS-IS — L1/L2, TLVs, SPF
- SD-WAN — policy-based path selection, SLA thresholds
- Levels 1–16 (beginner through advanced, see table above)
- Level 17: RSVP-TE traffic engineering
- Level 18: Segment Routing SR-MPLS
- Level 19: SRv6
- Level 20: SD-WAN dual-WAN policy
- Level 21: Complex multi-failure troubleshooting
- Campaign mode — "Build your own ISP" narrative arc
- macOS (primary dev platform, tested on 13+)
- Windows build
- Linux build
DaRealDaHoodie — design, engineering, everything
Claude Sonnet 4.6 (Anthropic) — co-author, pair programmer, protocol consultant, and the one who kept the RFC citations honest
Source available under the MIT + Commons Clause license — free to use, study, and modify for personal and educational purposes. Commercial use requires permission from PiMP Studios.