Following the internet shutdown that began on 18 July 2024 in Bangladesh, basic connectivity vanished almost overnight. Text messages failed to transmit. Web pages refused to load. Applications became unresponsive. Only traditional phone calls remained functional, forcing businesses to resort to voice communication. For many operators, the inability to reach clients or explain the disruption created immediate economic damage.

These events resurfaced during a presentation at APNIC 62, where Sumon Ahmed Sabir of Fibre@Home addressed a critical but often overlooked question: What happens to local network services when international connectivity disappears? The answer, it turns out, determines whether a region's digital economy can partially recover during an outage or collapses entirely.

Understanding the July 2024 Disruption

Precision matters when describing what occurred. The disruption was not a submarine cable failure. Internet Society Pulse and the Open Observatory of Network Interference (OONI) documented that restrictions on internet access began on 18 July. By that afternoon, connectivity across the broader economy had nearly vanished. Recovery started gradually after approximately five days. OONI recorded the complete blackout spanning 18 to 23 July, followed by targeted blocks on social media and messaging applications from 24 to 31 July.

The financial toll proved substantial. The e-Commerce Association of Bangladesh (e-CAB) calculated sector losses at roughly BDT 20 billion. Internet Society's NetLoss calculator put the figure at more than USD 21 million during just the first five days. While these remain estimates rather than audited accounts, they consistently demonstrate that severed connectivity carries severe economic consequences.

The Hidden Dependencies Nobody Plans For

Network operators face a consistent operational reality regardless of why international links fail: determining what continues functioning locally when external access ceases. Sabir emphasized that services capable of operating within a single economy often fail because their underlying infrastructure sits elsewhere.

His analysis identified several vulnerable components: Domain Name System resolvers positioned abroad, cloud-hosted application elements, remote APIs, time synchronization services, and mobile payment systems. Under normal circumstances, these dependencies remain invisible. During an outage, any single one can disable a service that could otherwise remain operational.

The experience felt simultaneous and indiscriminate—everything appeared to fail at once. Distinguishing between tools that stopped working because the network went down versus those that depended on external infrastructure became impossible in real time. Sabir's core recommendation: operators should answer this question before the next outage occurs, not during it. His guidance centered on minimizing external dependencies through strengthened local DNS infrastructure and preparation for prolonged disruptions.

The fundamental principle for operators is straightforward: locate services designed for local delivery that still depend on external infrastructure, then strategize how to reduce those dependencies.

Bangladesh's International Connectivity Structure

Bangladesh routes international traffic through a limited set of submarine and terrestrial pathways. SEA-ME-WE 4 and SEA-ME-WE 5 provide submarine capacity, complemented by terrestrial links crossing into India. This concentration underscores why route diversity matters operationally. When SEA-ME-WE 5 underwent maintenance in April 2026, users experienced degraded speeds and intermittent failures while SEA-ME-WE 4 remained operational.

Bandwidth requirements continue climbing, and additional international capacity is under development, including SEA-ME-WE 6. Expanded capacity and alternative routes enhance resilience. However, they do not eliminate the necessity of understanding which services intended for local use depend on infrastructure positioned internationally.

Patterns Across South Asia

India presented a parallel case during the same discussion. Ashutosh Zutshi of NEC India noted that international connectivity concentrates at relatively few landing points, particularly Mumbai and Chennai. Although India and Bangladesh differ dramatically in scale, both demonstrate the importance of geographic and network diversity in international connectivity alongside raw capacity expansion.

Immediate Actions for Network Operators

The session discussion outlined several actionable steps operators can implement without awaiting additional international connectivity:

  • Locate services dependent on infrastructure outside the economy.
  • Establish appropriate local DNS infrastructure and validate service behavior when international connectivity becomes unavailable.
  • Determine critical content and services suitable for local availability.
  • Exercise continuity procedures against extended disruptions, not merely short interruptions.

Measuring Resilience Beyond Capacity

Resilience discussions typically focus on available capacity. Sabir's presentation introduced an alternative metric: the percentage of a network that remains operational when international connectivity ceases. Bangladesh's experience demonstrates the relevance of this question. The insights apply far beyond the region's borders.