VoIP Multi-Network Laboratory
Independent Student PBX Networks with Shared Provider Infrastructure
VoIP Multi-Network Laboratory
This case study documents a hands-on VoIP learning environment designed for vocational telecommunications education.
The laboratory uses a multi-network architecture in which each student builds and manages an independent VoIP network while a central instructor-managed infrastructure provides shared provider and interconnection services.
Each student works with a dedicated router, laptop, virtual PBX environment, physical IP telephone, and softphone endpoints. This allows students to configure and troubleshoot a complete VoIP system rather than interacting only with a preconfigured centralized PBX.
Learning Environment
The laboratory integrates practical concepts including IPv4 addressing, LAN/WAN segmentation, routing, NAT, virtualized PBX deployment, SIP extensions, physical and software endpoints, SIP trunks, call routing, PBX services, port forwarding, and analog/VoIP interoperability.
Layered Network Model
- School / Enterprise Network:
10.0.0.0/8 - VoIP Laboratory / Provider Network:
172.16.0.0/16 - Student / Customer LAN:
192.168.1.0/24
Each student router connects its WAN interface to the shared laboratory/provider network while creating an isolated private LAN for the student’s PBX and VoIP endpoints.
Student Laboratory Environment
Each student operates a complete routed VoIP environment using a laptop, dedicated router, physical SIP/IP telephone, VirtualBox PBX, laptop softphone, and mobile softphone endpoint.
Progressive Learning Sequence
The Module 21 laboratory sequence develops the system progressively from virtualization and PBX installation through SIP endpoints, trunking, inbound/outbound routing, recordings, announcements, ring groups, queues, time-based routing, and IVR.
The result is a functioning student-managed telephone system in which later activities depend on services configured during earlier activities.
Central VoIP Infrastructure
A separate instructor-managed mobile platform provides the shared provider/interconnection network through a Linux/FreePBX/Asterisk server, Ethernet switching, routing infrastructure, and SIP testing endpoint.
Advanced Connectivity
After the individual systems are operational, students explore NAT and port forwarding by allowing an endpoint on another network to register to an extension hosted on their PBX.
Cross-Module Integration
When the same cohort completes both the Analog Telephony and VoIP modules, the two laboratory environments can be interconnected through a SIP trunk. The instructional roles are intentionally reversed: analog infrastructure is tested through VoIP in the Analog module, while VoIP infrastructure can reach analog endpoints in the VoIP module.