PKT Generator V1.0

Generate Cisco Packet Tracer 9 network topologies programmatically — from a Python script or an AI prompt.

No GUI. No manual dragging. Just describe your network, run the script, open the .pkt.

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What This Is

Cisco Packet Tracer saves topologies as encrypted, compressed XML (.pkt files). This toolkit reverse-engineers that format so you can:

• Generate complete, openable .pkt files from Python code
• Define buildings, devices, and cables in plain code
• Inject real IOS/IOS-XE configs into devices at generation time
• Use it as a base for AI-driven network topology generation

Tested against Packet Tracer 9.0.0.0810.

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Folder Contents

PKT_Generator_V1.0/
├── generator_base.py       ← main library (import from here)
├── pkt_tool.py             ← encrypt/decrypt .pkt files
├── assets/
│   ├── components.xml      ← PT9 device donor (all device types)
│   └── generic_shell.xml   ← minimal PT9 document skeleton
├── README.md               ← this file
├── AI_KNOWLEDGE_BASE.md    ← deep technical reference for AI agents
├── PORT_NAMES.md           ← empirically verified port names per device type
└── WORKFLOW.md             ← step-by-step generation workflow

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Quick Start

Requirements

• Python 3.10+
• Standard library only (no pip installs)
• Cisco Packet Tracer 9 (to open the output)

Generate the example topology

cd PKT_Generator_V1.0
python3 generator_base.py
# → ../labs/example_two_buildings.pkt

Open labs/example_two_buildings.pkt in Packet Tracer 9.

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Building Your Own Topology

Create a script that imports from generator_base.py:

import sys
from pathlib import Path
sys.path.insert(0, str(Path(__file__).parent / "PKT_Generator_V1.0"))

from generator_base import PhysicalWorld, clone_device, set_physical, build_link, generate

# 1. Define physical world
world = PhysicalWorld()
world.add_city("Campus")
world.add_building("DataCenter", city="Campus")
world.add_building("BuildingA",  city="Campus")

# 2. Clone devices (type, hostname, x, y, ios_config_lines)
router = clone_device("Router", "CoreRouter", "400", "200", [
    "hostname CoreRouter",
    "interface GigabitEthernet0/0/0",
    " ip address 10.0.1.1 255.255.255.0",
    " no shutdown",
    "end",
])
switch = clone_device("Switch", "SW_A", "200", "350", None)
pc     = clone_device("Pc",     "PC_1", "100", "500", None)

# 3. Place devices in physical world
phys, pp = world.inject_rack("DataCenter", "CoreRouter"); set_physical(router["el"], phys, pp)
phys, pp = world.inject_rack("BuildingA",  "SW_A");      set_physical(switch["el"], phys, pp)
phys, pp = world.inject_floor("BuildingA", "PC_1");      set_physical(pc["el"],     phys, pp)

# 4. Wire cables
def wire(links_el):
    build_link(links_el, router, "GigabitEthernet0/0/0", switch, "GigabitEthernet0/1")
    build_link(links_el, switch, "FastEthernet0/1",      pc,     "FastEthernet0")

# 5. Generate
generate("labs/my_topology.pkt", [router, switch, pc], world, wire)

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Supported Device Types

dtype	PT9 Model	Key Port Names
Router	PT8200	GigabitEthernet0/0/0 … 0/0/3
Switch	2960-24TT	FastEthernet0/1…0/24, GigabitEthernet0/1…0/2
Pc	PC-PT	FastEthernet0
Laptop	Laptop-PT	FastEthernet0
Server	Server-PT	FastEthernet0
ISA	ISA-3000	GigabitEthernet1/1, GigabitEthernet1/2 (not 0/x)
NetworkController	WLC	GigabitEthernet0, GigabitEthernet1
WirelessEndDevice	Access Point	Wireless0
MCUComponent	IoT MCU	Wireless0
Cloud	Cloud-PT-Empty	Port0

See PORT_NAMES.md for the full table with common mistakes called out.

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API Reference

PhysicalWorld

Manages the physical workspace tree (buildings, rooms, racks).

world = PhysicalWorld()
world.add_city("CityName")
world.add_building("BuildingName", city="CityName")

phys, pp = world.inject_rack("BuildingName", "DeviceName")   # router/switch/server
phys, pp = world.inject_floor("BuildingName", "DeviceName")  # PC/laptop/AP/IoT

clone_device(dtype, name, lx, ly, ios_lines)

Clones a device from assets/components.xml, patches all unique IDs, and optionally injects IOS config.

Returns a dict: {"el": Element, "ref": save_ref_id, "mem": dev_addr, "name": name}

set_physical(dev_el, phys, pp)

Writes WORKSPACE/PHYSICAL and WORKSPACE/PHYSICAL_CPUR into a device element. Always call after inject_rack or inject_floor.

build_link(links_el, dev_a, port_a, dev_b, port_b)

Adds a copper straight-through cable between two devices. dev_a and dev_b are clone_device() result dicts.

generate(out_pkt, all_devices, world, wire_fn)

Assembles the final XML, enforces the correct PT9 element order, and calls pkt_tool.py to produce the .pkt.

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How It Works

.pkt files are Twofish/EAX encrypted + zlib compressed XML. The encryption key is hardcoded in Packet Tracer itself. pkt_tool.py (included) handles both directions:

# Inspect any .pkt file
python3 pkt_tool.py decode -o output.xml input.pkt

# Re-encrypt after editing
python3 pkt_tool.py encode -o output.pkt input.xml

PT9 enforces strict schema validation on load — wrong element order, missing required fields, or incorrect port names cause silent rejection ("not compatible" or infinite loading). The generator handles all of this automatically.

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For AI Agents

If you are an AI being asked to generate a topology using this toolkit:

1. Read AI_KNOWLEDGE_BASE.md — it contains the full PT9 XML schema, ID generation rules, error table, and debugging strategy
2. Read PORT_NAMES.md — verify every port name before wiring a cable
3. Use generator_base.py as-is — do not rewrite helper functions
4. Always call inject_rack() or inject_floor() for every device, then set_physical() immediately after
5. Never set VERSION to anything other than 9.0.0.0810

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Debugging a Broken File

Symptom	Likely Cause	Fix
"corrupted Physical Workspace data"	UUID chain mismatch between PHYSICAL and PW tree	Call set_physical() with the exact values returned by inject_rack/floor
File hangs on "Please wait. Opening file…"	Wrong node TYPE codes or missing geometry in PW	Use PhysicalWorld — do not build PHYSICALWORKSPACE manually
"not compatible with this version"	Wrong port name, or missing IS_MANAGED_IN_RACK_VIEW / second TYPE in cable	Check PORT_NAMES.md; use build_link()
"requires version X.X"	Wrong VERSION tag	Must be 9.0.0.0810

Divide-and-conquer: generate with all devices but no links → then add links one by one → the first failing file identifies the bad cable.

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Background

This toolkit was developed through systematic reverse-engineering of Cisco Packet Tracer 9's file format — decoding native .pkt files, comparing XML structures, and empirically testing device/port/element combinations until files opened reliably. The work included:

• Cracking the encryption scheme (Twofish/EAX, existing tool)
• Mapping the required XML element order (21 top-level tags, strict)
• Discovering the correct PHYSICALWORKSPACE TYPE codes and geometry values
• Verifying port names for every device type by trial and error in PT9
• Identifying the two required-but-undocumented cable fields

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License

MIT