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Documentation Index

Fetch the complete documentation index at: https://mintlify.com/Mats2208/MCP-Packet-Tracer/llms.txt

Use this file to discover all available pages before exploring further.

No router model in Packet Tracer ships with Serial ports by default — they must be added through expansion modules before any serial WAN links can be drawn. More broadly, expansion modules let you add serial interfaces, additional Ethernet ports, and wireless adapters to routers already placed on the canvas at runtime. The MCP server powers the device off, installs the module in the specified slot, and powers the device back on automatically — no manual shutdown in the PT GUI required.

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Execution Order

PTBuilder enforces a strict ordering of operations: a module must be installed after the device is placed and before any links are drawn to ports that the module provides. Violating this order causes link creation to fail because the ports don’t exist yet. 
addDevice("R1", "2911", 100, 100);        // 1. Place the device
addModule("R1", "0/0", "HWIC-2T");        // 2. Install the module (adds Serial ports)
addLink("R1", "Serial0/0/0", "R2", "Serial0/0/0", "serial");  // 3. Draw the link
The MCP generator always emits addModule() calls between the addDevice() block and the addLink() block to respect this constraint.

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Slot Addressing

Slot identifiers are strings, not integers. The format differs by module family.
Module FamilyValid Slot StringsRouter Models
HWIC"0/0", "0/1", "0/2", "0/3"1941, 2901, 2911
NIM"0", "1"ISR4321, ISR4331
NM"1", "2"Router-PT, 2811, 2620XM, 2621XM
For HWIC slots, "0/0" and 0 address different slots. Always use the string form "0/0" to match PT’s internal slot semantics. Integers are accepted and auto-coerced, but prefer explicit string literals.
ISR G2 routers (1941, 2901, 2911) do not have NM slots — only HWIC and SM. To get 4 serial ports on a 2911, install two HWIC-2T modules in slots "0/0" and "0/1".

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Automatic Serial Module Selection

When the planner detects that serial links are required, it automatically selects and installs the correct module for the router model. You never need to specify serial modules manually for planned topologies.
Router ModelAuto-Selected ModulePorts Added
1941HWIC-2TSerial0/0/0, Serial0/0/1
2901HWIC-2TSerial0/0/0, Serial0/0/1
2911HWIC-2TSerial0/0/0, Serial0/0/1
ISR4321NIM-2TSerial0/1/0, Serial0/1/1
ISR4331NIM-2TSerial0/1/0, Serial0/1/1

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Key Modules Reference

ModuleSlot TypePorts AddedDescription
HWIC-2THWICSerial0/0/0, Serial0/0/12-port serial WAN — most common
HWIC-4ESWHWICFa0/1/0–Fa0/1/34-port Ethernet switch
HWIC-1GE-SFPHWICGigabitEthernet0/0/01-port GigE SFP uplink
HWIC-8AHWICAsync0/0/0–Async0/0/78-port async serial
WIC-1TWICSerial0/0/01-port serial
WIC-2TWICSerial0/0/0, Serial0/0/12-port serial
NIM-2TNIMSerial0/1/0, Serial0/1/12-port serial for ISR 4000 series
NIM-ES2-4NIMGig0/1/0–Gig0/1/34-port GE Layer 2 for ISR 4000
NM-1FE-TXNMFastEthernet1/01-port FastEthernet copper
NM-4ENMEth1/0–Eth1/34-port Ethernet
NM-4A/SNMSerial1/0–Serial1/34-port serial (legacy routers only)
NM-ESW-161NMFa1/0–Fa1/1516-port Ethernet switch module

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pt_add_module vs pt_install_modules_batch

pt_add_module

Installs a single module in one call. Validates module existence, slot format, device presence in PT, and model compatibility before sending. Each call triggers a full power-cycle of the device.

pt_install_modules_batch

Installs N modules across one or more devices in a single power-cycle. Strongly recommended when installing multiple modules — avoids the per-call power-on delay that can time out the bridge bootstrap.
Use pt_install_modules_batch whenever you need more than one module. Installing 2 × HWIC-2T on a 2911 via pt_add_module requires two separate power-cycles; the same operation via batch completes in one.

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Batch Example

{
  "modules": [
    { "device": "R1", "slot": "0/0", "module": "HWIC-2T" },
    { "device": "R1", "slot": "0/1", "module": "HWIC-2T" },
    { "device": "R2", "slot": "0/0", "module": "HWIC-2T" }
  ]
}
This installs four serial ports on R1 and two on R2 in a single bridge transaction.

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Listing Available Modules

Use pt_list_modules to browse the full catalog of 151 modules, with optional filtering by router model or category: 
{ "router_model": "2911" }

{ "category": "router_hwic" }
Valid category values: router_nm, router_hwic, router_nim, router_wic, pt_router_nm, sfp, and more.

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