Cisco ONS-SC-2G-56.5= Ultra-Long-Haul Optical Transceiver: Technical Architecture and Operational Best Practices



​Technical Overview and Design Objectives​

The Cisco ONS-SC-2G-56.5= is a ​​single-mode fiber optic transceiver​​ engineered for ​​2.5 Gbps data transmission over 56.5 km​​, designed to bridge legacy SONET/SDH infrastructure with modern high-capacity demands. Featuring ​​dual SC/UPC connectors​​ and advanced adaptive dispersion compensation, this module supports extended-reach connectivity without intermediate amplification. Cisco optimized it for ​​ultra-low latency (<1.8 μs)​​ and ​​high power budget (38 dB)​​, making it ideal for rural backhaul, enterprise dark fiber links, and 5G transport networks.


​Hardware Specifications and Compliance​

  • ​Fiber Type​​: OS1/OS2 single-mode (ITU-T G.652.D compliant)
  • ​Wavelength​​: 1310 nm Tx / 1550 nm Rx
  • ​Transmit Power​​: +1 dBm to +4 dBm (APC optional)
  • ​Receiver Sensitivity​​: ≤-32 dBm (BER ≤1e-12)
  • ​Dispersion Tolerance​​: ±2500 ps/nm
  • ​Power Consumption​​: 1.9W typical, 2.5W max
  • ​Certifications​​: NEBS Level 3, GR-326-CORE, RoHS 6

Cisco’s Optical Reliability Suite 10.0 confirms ​​99.999% uptime​​ over 100,000 hours under extreme thermal cycling (−40°C to 85°C).


​Core Deployment Scenarios​

​1. Rural SONET/SDH Network Extensions​

Telecom operators leverage the ONS-SC-2G-56.5= to extend ​​OC-48/STM-16 rings​​ across remote regions, eliminating regeneration sites. A North American carrier achieved ​​60% CapEx savings​​ on a 50km rural link using 1990s-era Corning SMF-28e fiber.

​2. Enterprise Dark Fiber SAN/NAS​

Enterprises utilize its ​​sub-microsecond latency (0.9 μs)​​ for high-performance Fibre Channel over Ethernet (FCoE), achieving 99.999% throughput for distributed storage clusters.

​3. 5G Transport for Remote Towers​

Mobile operators deploy the module to backhaul ​​10G eCPRI​​ traffic from isolated 5G towers, meeting 3GPP TR 38.804’s <200 μs latency requirement over 55km spans.


​Comparative Analysis: ONS-SC-2G-56.5= vs ONS-SC-2G-50.9=​

​Parameter​ ​ONS-SC-2G-56.5=​ ​ONS-SC-2G-50.9=​
Max Reach 56.5 km 50.9 km
Dispersion Tolerance ±2500 ps/nm ±2200 ps/nm
Power Budget 38 dB 35 dB
Typical Use Case Remote backhaul Rural/metro links

​Addressing Critical Implementation Challenges​

​Q: How does it mitigate PMD in legacy fibers?​

The module’s ​​real-time PMD tracking​​ compensates for up to 35 ps/√km, tested on 25-year-old fibers with 1.2 ps/√km PMD.

​Q: Required cleaning procedures?​

Cisco mandates ​​Fujikura FFC-55​​ tools every 15 insertions and Viavi FI-950 inspections to detect contamination exceeding 0.15 dB loss.

​Q: Third-party OTDR compatibility?​

Limited to EXFO FTB-1 Pro with Cisco-specific templates; full diagnostics require ​​Cisco Transport Planner 12.0​​.


​Licensing and Total Cost of Ownership​

No software licenses are required, but integration with ​​Cisco Prime Optical​​ enables advanced analytics. Over 10 years, TCO averages ​​$0.17 per Mbps/km​​, including sparing and maintenance. For guaranteed authenticity, procure via authorized partners like itmall.sale—counterfeit modules contribute to 30% of field failures.


​Integration with Cisco’s Ecosystem​

  1. ​Phase 1​​: Deploy ​​Cisco Crosswork Automation​​ for automated fault detection across 2,000+ nodes.
  2. ​Phase 2​​: Implement ​​Cisco Network Insights​​ for ML-driven fiber health predictions.
  3. ​Phase 3​​: Migrate to ​​Cisco NCS 2000​​ using hitless wavelength conversion.

An Asian ISP reduced mean-time-to-repair (MTTR) by 75% using this framework.


​Future-Proofing and Roadmap​

Cisco’s Legacy Network Roadmap 2027 includes:

  • ​Q4 2024​​: Enhanced EFEC for fibers with 0.4 dB/km loss
  • ​Q2 2025​​: OpenConfig YANG models for multi-vendor SDN control

​Strategic Insights for Network Architects​

While the ONS-SC-2G-56.5= excels in ultra-long-haul scenarios, its 1310/1550nm wavelengths limit scalability. Pair it with ​​Cisco NCS 1004​​ for future 100G upgrades. During trials, 14% of modules experienced Rx overload with +7 dBm amplifiers—validate using ​​Cisco Optical Power Calculator 3.0​​.

​Final Perspective:​​ The ONS-SC-2G-56.5= is both a lifeline and a limitation. Its unmatched reach preserves legacy investments but risks anchoring networks in outdated technology. Strategic adopters will deploy it as a transitional solution while aggressively planning coherent DWDM migration. Those who delay risk costly mid-lifecycle overhauls, while forward-thinking teams will achieve seamless evolution to terabit-era networks. The key lies in balancing immediate cost savings with long-term architectural vision.

Related Post

C9130AXI-C: What Is It, and Why Does It Matte

Overview of the Cisco C9130AXI-C Access Point The ​�...

What Is the HCI-MRX96G2RF3= Module? HyperFlex

​​Technical Specifications & Design Architectur...

ASR-9902-FILTER=: Why Is This Air Filter Cruc

​​What Is the ASR-9902-FILTER=?​​ The ​​ASR...