N+1 Resilience Across the Pacific: The Power of Sea Cable Systems

Global data traffic characterises the trans-Pacific area as the most important and heavily trafficked region. It is constantly passing enormous amounts of information that are of significant concern to businesses, governments, and entire economies across the globe. Due to its tremendous dependency, the trans-Pacific subsea cable infrastructure is highly vulnerable to natural disasters. Events such as natural calamities, accidents during cable laying, and equipment malfunction can halt data flow. When problems of this nature can have disastrous consequences, it clearly indicates the need to make connectivity systems very resilient. N+1 resilience is one of the most reliable methods for ensuring the trans-Pacific connection is never broken.

Understanding N+1 Resilience in Trans-Pacific Architecture

The Imperative of Physical Diversity and Redundancy

The idea of N+1 resilience involves designing networks to ensure that no single failure point disrupts service. The case of the trans-Pacific underwater cable systems makes this necessity very crucial and, at the same time, complicates it technically. When contemplating redundancy, one should not limit oneself to just the line that is on the map. A subsea cable system includes landing stations, repeaters, power-feeding gear, and terrestrial backhaul lines. In the case of N+1, several cable routes would be established that would be widely dispersed, so if one route fails, be it due to a natural disaster, an equipment malfunction, or a cable cut, it will not impact all the links at the same time.

Realistic implementation of the N+1 submarine cable plan requires more than just a second cable connection. Each of the paths must end in a different city or area, use separate landing stations that have their own power supplies, take different terrestrial backhaul routes, and, if possible, be owned or managed by different consortiums to reduce the risk of operational sharing. If two cables use the same landing stations, ducts, or inland fibre links, a single issue can cause both of them to go off the network. It is for this reason that physical variation is still the major aspect of trans-Pacific resilience. The Pacific's geological makeup, identified by the Ring of Fire and unforeseen deep-sea seismic activity, compels firms to not merely seek redundancy but rather strive for the total separation of cable lines. In this manner, interconnection failure will not incapacitate the entire network.

The Economic Impact of Cable Cuts

Cable cuts are common scenarios. They happen, among other reasons, due to fishing activities, ship anchors, natural disasters, and just the normal wearing out of the equipment. When the breakdown or shutdown of a significant connection across the Pacific Ocean occurs, the financial repercussions are rapid and severe. Companies that depend on the N-only design may experience slowdowns, lost data, and total shutdowns that stop trading platforms, supply chain systems, real-time communications, and cloud applications from working, leading to losses of millions of dollars. The whole world of e-commerce is affected, global tech teams cannot access remote sites, and consumers are left disappointed – all these things happen instantly. The financial loss increases with each delayed transaction or interrupted data transfer.

It is a fact that the duplication of undersea cable systems is a highly costly affair; however, the cost of downtime is way higher. A single outage of a few hours' duration might result in the loss of more value than the cost of redundancy over years of operation. The global nature of the business makes it easy to see the answer: refusal to invest in a +1 link is not only an optional decision but also a forced one; it is practically an insurance policy that protects the flow of mission-critical data, keeps the business running, and prevents the immense loss of revenue and the damage to the company's image that accompany a cable failure.

Designing and Implementing a Resilient Architecture

Utilising BGP for Automated Failover

For developing an N+1 architecture, not only are different cable paths required but also a system that will automatically failover and transfer global traffic to the secondary link in a matter of seconds whenever the primary link goes down. This is precisely where the Border Gateway Protocol (BGP) comes into play. BGP is responsible for the route publishing and selection over both the primary (N) and backup (+1) undersea cable links. This means that communication is uninterrupted and there is no need for human intervention.

Usually, companies modify BGP settings such as weight, local preference, AS-path prepending, and communities to ensure that the primary link, which is less time-consuming and has less latency, is always the one selected during normal operation. The main trans-Pacific cable is assigned higher values for local preference, while the impacting AS-path prepending helps control the routing of networks. Community tagging informs the upstream providers which routes are your favourites, thus preventing them from becoming unstable or overloaded. In fact, most networks set up Bidirectional Forwarding Detection (BFD) along with BGP to quickly detect any outages. BFD detects failure in less than a second and then automatically withdraws the route of the primary path for the secondary path when it becomes worse.

It's very crucial to get the settings right. If the attributes are not properly set, then routing flaps, blackholing, or partial failover could occur. N+1 systems that are designed with care employ strict routing rules to prevent asymmetry and to assure that BGP smoothly reconverges. When it is done correctly, the failover of submarine cables is totally seamless and automatic. While a cable is down, not only do applications remain available, but also data continues to flow, and global operations do not stop.

The Role of Cloud Providers and Carrier Services

Big cloud providers and global carriers indirectly give most businesses trans-Pacific N+1 resilience. Hyperscalers like AWS, Google Cloud, and Microsoft Azure, for instance, possess powerful private backbone networks that rely on several submarine cable systems that are located all over the Pacific and used by them. These architectures are designed to provide redundancy at this level, so they can provide N+1 resilience as a built-in, fully managed part of their cloud and network services.

They apply the same model as global carriers and subsea consortia. They form strong backbones with built-in failover by purchasing capacity on multiple routes that are geographically distant from each other. They then sell this resilience to users as part of their connection services. If a company cannot afford it or lacks the size or operational focus to implement its cable diversity strategy, the only way to ensure a connection across the Pacific is to partner with a cloud provider or carrier. These companies bear the engineering complexity, operational risk, and capital costs associated with ensuring global networks are always online and ready for N+1.

Testing and Continuous Validation for Business Continuity

Establishing Performance Benchmarks and RTO

If the resilient architecture doesn't function as planned when real issues arise, it won't be useful. To avoid this, the companies should conduct comprehensive testing on the main (N) and secondary (+1) routes in a realistic setting. In addition, the key performance indicators, such as latency during peak and off-peak periods, throughput capacity, packet loss, and jitter, must be monitored and recorded regularly to ensure that both links are capable of carrying the full production workloads without any issues.

It is crucial to establish and achieve a certain recovery time objective (RTO) along with the measures that determine the time taken to move traffic from the primary to the secondary link without any impact on the business. For modern applications, an RTO measured in seconds rather than minutes is very critical. This requires setting up automatic failover systems supported by extensive monitoring, alerting, and ongoing testing. If the +1 path cannot support production traffic or if the failover duration exceeds the set RTO, the entire resilience strategy collapses. Through continuous validation, both the cable routes are kept in satisfactory condition, performing well, and being able to cope with sudden counteracting changes in traffic.

Most companies indirectly obtain trans-Pacific N+1 resilience by leveraging major cloud providers and global carriers. Examples of such hyperscalers are AWS, Google Cloud, and Microsoft Azure, which operate vast private backbone networks over various submarine cable systems that are located around the Pacific. Their core architectures are purposely built to have such redundancy, thus allowing them to provide N+1 resilience as a default and fully managed feature of their cloud and network services.

Global carriers and subsea consortiums adhere to the same business model. They establish robust backbones with embedded failover by purchasing capacity on a cable system where there is no competitor.

Scheduled Failover Drills and Stress Testing

Continuous validation is the most effective way to demonstrate resilience. This involves the performance of planned, deliberate failover drills, during which the primary (N) connection is intentionally taken off the network to verify that the backup (+1) route operates exactly as intended. These examinations ensure that routeing tables are accurately updated, BGP reconvergence occurs in a timely manner, and the +1 link copes with the maximum production traffic without suffering from excessive delay, jitter, or throughput loss. Moreover, they confirm that all applications and critical services are operating at full capacity during the transition.

Frequent stress testing turns theoretical resilience into actual reliability. If these drills are conducted quarterly or even more frequently, the companies not only lose all the uncertainties but also are able to discover the configuration gaps before the outages happen, and they become sure that their Pacific connection will be reliable in the event of real failures.

N+1 resilience has become a requirement for the transmission of data across the Pacific Ocean to be both safe and reliable. N+1 resilience is a way of using different types of systems and different locations of undersea cable to reduce the risk of a major cable breakage. The combination of redundant physical infrastructure and automated failover protocols (e.g., BGP) ensures the continuous presence of critical data flows.

Moreover, the use of cloud providers and service carriers not only improves resilience but also reinforces this entire system as it is applied to managed networks that can handle global scale. Nonetheless, frequent testing and validation are still critical for the continuity of a business.

Today, since constant connectivity is essential for the economy and using digital technologies, the best way to ensure a steady flow of data across the Pacific is to implement N+1 resilience everywhere. Are you ready to validate, strengthen, or modernise your trans-Pacific resilience strategy? Connect with the Nexthop team today—we'll help you architect, test, and operationalize true N+1 reliability tailored to your global network.