Dual-Route Protected 40Gbps OTN DWDM Network

Project Overview

A regional broadcasting and telecommunications operator required a reliable optical transmission system to interconnect two major service centers located approximately 200 km apart.

The objective was to build a carrier-grade optical transport network capable of supporting multiple mission-critical services, including digital television broadcasting, broadband Internet access, IPTV interactive services, and data transmission.

To ensure high availability and future scalability, the operator deployed a dual-route fiber transmission architecture based on advanced OTN (Optical Transport Network), DWDM (Dense Wavelength Division Multiplexing), and CWDM optical transmission technologies.

The solution provides high-capacity optical transport, flexible wavelength expansion, and multi-layer protection to guarantee uninterrupted service delivery across the entire network.

Network Challenges

Long-Distance Fiber Transmission with High Reliability Requirements

The transmission distance between the two service locations exceeded 200 km, requiring a robust optical transport solution capable of maintaining stable signal quality over multiple fiber spans.

The existing fiber infrastructure consisted of:

Primary optical fiber route:

• Approximately 195 km total distance
• 6 optical spans
• Multiple intermediate sites available for optical amplification

Secondary protection fiber route:

• Approximately 213 km total distance
• 10 optical spans
• Multiple backup amplification locations

The network needed to provide:

• High availability transmission
• Automatic protection switching
• Low latency service delivery
• Future bandwidth expansion capability
• Support for multiple service interfaces

Solution Architecture

Dual-Route Protected OTN + DWDM Transmission System

The deployed solution adopts a dual optical path architecture using OTN-based transmission equipment combined with DWDM wavelength multiplexing technology.

The network architecture includes:

• Optical Transport Network (OTN) platform
• DWDM wavelength division multiplexing system
• Optical Line Protection (OLP)
• Optical amplification modules
• Integrated network management system

The system creates an independent protection path between the two core locations, ensuring continuous operation even in the event of fiber cuts or optical equipment failures.

Transmission Capacity and Service Support

High-Capacity 10GbE Optical Transport

The system supports a minimum transmission capacity of 40Gbps, with scalable wavelength expansion for future network growth.

Current service deployment includes:

Each site provides multiple 10GbE service interfaces, enabling flexible service aggregation and transport.

Key Technical Features

1. DWDM-Based Long-Haul Optical Transmission

The system supports:

• C-band and L-band wavelength operation
• ITU-T G.694.1 compliant wavelength planning
• 50GHz / 100GHz channel spacing
• Minimum 8 wavelength channels
• 10Gbps or higher capacity per wavelength

The DWDM architecture enables efficient utilization of existing fiber resources without additional fiber deployment.

2. Multi-Layer Network Protection

To improve network reliability, multiple protection mechanisms are implemented:

Optical Layer Protection

• 1+1 optical line protection
• Dual fiber route protection
• Automatic optical path switching

Transport Layer Protection

• OTN channel protection
• Service-level protection
• Traffic recovery mechanism

The complete protection architecture ensures rapid recovery and minimizes service interruption.

3. Advanced Optical Amplification Technology

For long-distance transmission, optical amplifier modules are deployed at intermediate locations.

Key capabilities include:

• Automatic gain control (AGC)
• Gain flatness optimization
• Multi-channel optical power balancing
• Stable long-distance signal amplification

These functions maintain consistent optical performance across different wavelengths and transmission distances.

4. Comprehensive Network Monitoring and Management

The optical transport system integrates centralized monitoring capabilities.

The management platform provides real-time monitoring of:

• Optical power levels
• Laser status
• Temperature information
• Optical signal quality
• Bit Error Rate (BER)
• Equipment operating status

The system supports:

• SNMP-based monitoring
• Remote network management
• Performance analysis
• Fault alarm reporting

Performance and Reliability

The deployed optical transport system delivers carrier-grade performance with:

• BER performance better than 10⁻¹²
• High channel isolation
• Stable wavelength transmission
• Fast protection switching
• 24/7 network availability

The modular hardware architecture enables future upgrades without replacing the existing transmission infrastructure.

Scalability and Future Expansion

The solution was designed with long-term network evolution in mind.

Future upgrade possibilities include:

• Increasing wavelength channels
• Expanding transmission capacity
• Supporting higher-speed optical interfaces
• Adding additional service cards
• Migrating toward higher-capacity OTN networks

The flexible platform allows operators to expand bandwidth according to future broadband and multimedia service requirements.

Deployment Environment

The optical transport equipment supports telecom-grade operating conditions:

• Standard rack-mounted installation
• 220V AC power supply compatibility
• Wide operating temperature range
• High-reliability industrial design

The system is suitable for:

• Broadcast networks
• Telecom backbone networks
• Government communication networks
• Utility fiber networks
• Mission-critical optical infrastructure

Application Scenario

This project demonstrates how OTN and DWDM optical transmission technology can be used to build a reliable long-distance communication network for:

• Digital TV broadcasting
• IPTV service delivery
• Broadband Internet transport
• Enterprise data communication
• Regional telecom backbone connectivity

By combining dual-route fiber protection, wavelength multiplexing, and intelligent optical management, the solution provides a highly available and scalable optical transport infrastructure.

Project Highlights

✓ 200km+ Long-Haul Fiber Transmission Network
✓ Dual Fiber Route Protection Architecture
✓ 40Gbps Optical Transport Capacity
✓ Multiple 10GbE Service Interfaces
✓ OTN + DWDM Integrated Transmission Solution
✓ Optical Line Protection (OLP) for High Availability
✓ Carrier-Grade Network Management
✓ Future-Proof Bandwidth Expansion Capability