Migrating Workloads to Submarine Networks: A Practical IT Guide

Submarine cable systems, which are installed below the sea, are responsible for nearly 95% of the total international data traffic that passes through the continents, and they can be considered the invisible backbone of the world's internet. Their incredible bandwidth and the smallest amount of time for data to travel across them made them the perfect infrastructure for live digital experiences, AI-powered workloads, and applications spread all over the world. For the new-age global firms, connecting their operations through underwater cables is not an option anymore; they have to invest in it strategically. Super-low latency connections across geography can yield faster applications, better user experience, and a strong advantage over competitors.

Nonetheless, the process of switching the existing workloads to the new undersea networks comes with the same kinds of issues that are usually associated with major infrastructure changes. It requires the very meticulousness that comes with advanced planning, having strong architectural bases, and fine-tuning the application layer. The guide offers an in-depth review of the critical issues that must be solved by the global IT and network teams before they embark on such a change.

Strategic Planning and Geo-Placement

Latency Mapping and Cable Selection

Migrating workloads to submarine networks involves controlling latency as the first step, which is done by determining the cable systems with the least physical distance between your origin and destination areas. Submarine cable delay is mainly affected by distance and fibre routing; hence, the choice of the cable—or the combination of cables—sets the minimum performance that your applications can achieve. Even a few milliseconds saved over a transoceanic route can greatly impact the performance of financial trading platforms, real-time collaboration applications, and AI inference pipelines.

For such a task, companies should use modern planning tools, cable-route databases, and commercial telemetry solutions to create an accurate latency map. The resources help the teams to see the physical paths, to compute the delays of the signals, to compare the different paths and to search for the opportunities to have the different paths. The aim is to find the undersea cables that provide the most straightforward, quickest links between the continents with minor unnecessary deviations through the landing points.

The location of a cable's termination and the structure of its ownership are factors of equal weight. A cable may have the least ocean distance, but it will still suffer from inland latency penalties if its landing station is situated far from your intended data centres or cloud regions. At the same time, consortia and structures of ownership have an effect on capacity access, procurement processes, and stability overall; some systems offer open access to bandwidth while others restrict the usage to partners. Taking these things into account at the beginning helps to ensure that your design is not only high-performing but also long-lasting.

Furthermore, consider the long-term scalability. A lot of the existing systems are compatible with very sophisticated coherent optics and very fast upgrade cycles, which would make them ready for the coming workload increase. Choosing cables with strong operational management, well-maintained landing sites, and clear growth paths is the right way to position your global network design for performance and stability in the long run.

Cloud Proximity and Data Sovereignty

The subsequent important selection after the best submarine cable systems have been picked is the location of the workload. If the intention is to get the maximum benefit of the trans-oceanic connection having the ultra-low latency feature, then the workloads need to be situated very close to the landing stations—in on-net data centres or cloud areas which are directly linked to the specific cables, if possible. The majority of the cloud service providers have set up micro or edge regions next to the important landing places where they operate, thus reducing the backhaul distances and increasing the latency benefits. The deployment of workloads in these strategically located regions leads to a reduction in the journey time before the data reaches the undersea cable, which in turn benefits latency-sensitive applications like VR streaming, distributed storage replication, and worldwide SaaS platforms.

However, it is very clear that proximity alone is not enough. Cloud region placement influences not only where the data is but also where it is physically certified. Organisations have to navigate the tangled web of data sovereignty requirements, cross-border transfer limits, and cloud-specific compliance standards. A number of jurisdictions impose quite strict rules regarding how citizen, financial, or regulated data is held and moved. Before they commit to locations adjacent to the landing sites, enterprises need to take not only the local legislation but also their internal governance standards into account. It is essential to strike a balance between performance and regulatory obligations in order to make global workload migrations both fast and compliant.

Architectural Design for Resilient Interconnectivity

Layered Redundancy and Cable Diversity

Probably, there’s no business that solely relies on one submarine cable. While cable problems resulting from ship anchors, natural calamities, or equipment failures are very rare, they do happen and are unavoidable nonetheless. One single cut across the ocean can take repairs for days or even weeks, during which any organisation without redundancy would suffer a very long downtime.

Your plan must consist of a minimum of two underwater cables that are physically separated from each other, preferably the ones operated by different consortia and the ones ending at different locations. This way, when one system fails, your traffic is routed to a different path automatically.

Having redundancy designed for multiple layers:

• Physical path diversity: Make sure the cables do not take the same sea floor route.
• Geographic diversity: Put the landing places in different cities or even countries.
• Logical diversity: Configure the routing so that the traffic is moving to the best available path dynamically.
• Vendor diversity: Acquire the capacity through different operators to minimise the risk.

Businesses that treat submarine cable selection the same way as cloud availability zones will be much more assured of continuity and will also not have single points of failure throughout the continents.

Utilising Wavelength Services vs. Cloud Gateways

Generally, enterprises pick either of the two connectivity models when they want to consume submarine network bandwidth:

• Wavelength Services (managed or dark fibre)
  • High-performance users such as hyperscalers, financial trading platforms, and media distribution networks usually rent wavelength services directly from undersea cables. It enables companies to have exclusive capacity with the lowest possible latency and predictability. Dark fibre offers additional control since companies can light and monitor it themselves, but it needs special optical knowledge, mature operations, and constant management overhead.
• Cloud Provider Dedicated Gateways
  • Rather, many companies opt for dedicated cloud connectivity services, like AWS Direct Connect, Google Cloud Interconnect, or Azure ExpressRoute. Such gateways simplify the complexities of submarine cable selection and route the traffic through the best, pre-engineered trans-oceanic routes. They are nothing but a great combination of performance, ease of use, and cost, and they are very much linked with the cloud ecosystems, even though they do not provide full customisation of the direct wavelength services.

Your need for latency, your financial plan, and future scalability intentions will determine the appropriate networking model.

Firms with forecasted and extremely low latency workloads might think of leasing direct wavelength capacity as a cheap solution.

Nevertheless, the rest would not have to compromise on high performance and operational simplicity because they have just adopted cloud-integrated gateways.

Technical Execution and Application Optimisation

BGP and Routing Optimisation

Once you have achieved both physical and logical connectivity, the next step is to make sure that the traffic follows your intended low-latency path. The Border Gateway Protocol (BGP) plays a crucial role in this.

To influence the routing decisions, you need to implement precise BGP configurations.

• AS-Path Prepending: Alter the outbound advertisements in such a way that the alternative paths appear less attractive to the neighbouring networks.
• Local Preference Tuning: Give priority to the preferred underwater connections within your local Autonomous System (AS).
• Community Tagging: Simplify the routing policies for distributed systems through automation.
• Selective Announcements: Determine which prefixes your network will share with which peers.

Correct manipulation of these settings ensures that packets traverse the quickest cable while still maintaining the failover feature. If BGP is not carefully architected, your traffic could be routed through less desirable paths; thus, the advantages of your submarine connectivity design would be lost.

Application and Protocol Tuning

Long-distance communication will always result in unavoidable latency, regardless of how short the submarine path is or how excellent the selection of routes may be. At this point, implementing application-level optimisations becomes essential. After minimising the physical delay, the next battleground is usually the protocol's behaviour and application design. The tuning of TCP/IP parameters, the request pattern optimisation, and the acceleration technology's exploitation can collectively lead to the establishment of a performance level that is significantly higher than that of trans-oceanic links.

The techniques most commonly used include:

• Increasing the TCP Window Size: Larger windows prevent bandwidth and latency on the path from being a constraint, as they cut down the number of necessary retransmissions greatly.
• Activating TCP Fast Open or selective ACK channels: The capabilities are indeed a win-win since they reduce the total time spent in handshaking, speed up the first data transfer, and enhance the long-distance flow control.
• Implementing app-specific accelerators, such as LAN optimisers, caching proxies, media accelerators, or protocol-aware proxies, can efficiently manage acknowledgements, data bursts, and caches, thereby minimising the impact of inherent delays.
• Changing the architecture of chatty applications involves reducing the number of round trips, which minimises the compounding of transoceanic latency when synchronous request/response patterns are used.

Global latency-tolerant applications outperform those that simply relocate to a different continent without any modifications.

Shifting workloads to underwater networks is not an innovative concept anymore; rather, it is a strategy that businesses having a demand for extremely low latency, worldwide access, and rapid connectivity would prefer to execute. A successful mix of careful planning, smart task placement, strong backup systems, effective routeing, and careful adjustments at the application level leads to success.

By incorporating these methods, companies not only place themselves in a position to offer fast and reliable global services but also to meet the performance requirements of the present day.

Is your global networking strategy ready for optimisation? The Nexthop Team is available to help you take the next step.