Building resilient networks: Navigating the evolution of technologies and redundant fibre strategies 

Daniel Strezov, Yafibr’s Chief Operating Officer, explains the
role of physical diversity in establishing true network redundancy.

The continuous evolution of network technologies has shaped our current digital landscape, facilitating faster and more reliable data transmission. Significant advancements have been made to meet the escalating demands for speed, reliability, and resilience.

But to navigate the rapid evolution of technologies, network architects have to build resilient networks. The key to achieving this, is in establishing physical diversity.

How network technologies have evolved

In the last 30 years, industry leaders, vendors, engineers, and scientists have invested a lot of effort in developing and implementing numerous protocols and technologies. The main aim of this has been to fulfill the ever-growing demands, ensuring convergence times in the sub-second range. Technologies like BLSR, APS, STP, ERSP, LAG, BFD, BGP, OSPF, and FRR are just a fraction of the comprehensive toolkit currently employed to fortify the resilience of both private ISP and Telco networks, as well as the public internet.

This technological progress, along with powerful network equipment, has enabled global connectivity, instant internet access, remote work capabilities, and seamless data exchange on a scale previously unimaginable. 

The risk of singular physical links  

There are a multitude of technologies and protocols out there, all with one thing in common – they rely on underlying physical infrastructure. It’s crucial to recognise the importance of this physical infrastructure, which often takes the form of fibre-optical networks.

Regardless of the deployed technologies, fibre-optical network links can unfortunately become a single point of failure. In the complex landscape of networking and ISP markets, where the physical network owner and capacity/service providers are often distinct entities, network engineers may face challenges in properly mapping logical links to the actual physical network or utilizing diverse physical paths. The severity of this risk is underestimated sometimes, or, due to practical constraints, achieving diverse paths is financially unfeasible or physically impossible. 

Lessons learnt from major outages  

Even with the advancements in protection technologies, the reliance on a single physical link remains a critical vulnerability.

Africa was hugely affected by a sub-sea cut on 14 March this year. Many of us will also remember the undersea cable cut in West Africa on August 6, 2023. It resulted in severe network disruptions affecting millions of users. Another noteworthy occurrence was a fibre cut near Frankfurt on February 15 2023 causing over 200 canceled flights at a major European airport.

But despite the devastating effects, what did these outages have in common? The answer is simple – a lack of physical diversity. In each of the cases, multiple fibre-optical cables running together were cut, highlighting the lack of diversity. Restoring such damaged physical infrastructure is often a costly and time-consuming endeavor, with downtime that directly affects operations and bottom-line. 

The importance of redundant fibre links   

To overcome the challenge of a single point of failure, network architects must prioritize the implementation of redundant fibre links. This entails deploying physical diversity, ensuring the existence of multiple independent routes for data transmission. Redundant fibre links significantly enhance network resilience, mitigating the risk of widespread outages and minimizing downtime.

Responsibility and opportunity for network architects  

It is a network architect’s responsibility to design networks capable of withstanding unforeseen challenges. Through strategic deployment of redundant fibre links and optimization of protection technologies, architects have a unique opportunity to build more resilient networks. This not only safeguards against service interruptions but also fosters overall customer satisfaction and trust in the network’s reliability. 

In the ever-evolving realm of network technologies, the importance of redundancy and resilience cannot be overstated. Layer 2 and Layer 3 protection technologies are pivotal in mitigating the impact of failures, and their effectiveness is maximized when complemented by redundant fibre links.

Armed with knowledge and advanced tools, network architects play a crucial role in designing robust and resilient fibre-optical backbone networks capable of withstanding the challenges presented by the digital age. 


APS: Automatic Protection Switching
BFD: Bidirectional Forwarding Detection
BGP: Border Gateway Protocol
BLSR: Bidirectional Line Switched Ring
ERSP: Ethernet Ring Protection Switching
FRR: Fast Reroute
LAG: Link Aggregation Group
OSPF: Open Shortest Path First
STP: Spanning Tree Protocol

Daniel Strezov, Yafibr’s Chief Operating Officer, explains the role of physical diversity in establishing true network redundancy.

With a career spanning over 17 years in the European internet industry, Daniel is an experienced telecoms engineer. He previously held the position of Manager of Fixed Networks at Huawei Bulgaria. Daniel demonstrates robust operations and management skills –he has successfully led substantial teams of experts and served as Technical Director in various large telecom rollout and swap projects across Europe.

Share This