Pakistan Internet Slowdown Due to Red Sea Subsea Cable Faults and Rerouting

Multiple subsea fibre‑optic cable faults in the Red Sea produced a measurable slowdown for Internet users across Pakistan, forcing carriers and cloud operators to reroute traffic, warn customers of higher latency, and expose the fragile link between cloud performance and the physical seabed infrastructure that carries most international data.

Background​

The global internet runs on a physical spine of submarine (subsea) fibre‑optic cables that carry the vast majority of cross‑border data. A handful of maritime corridors funnel enormous volumes of traffic; the Red Sea and its approaches — notably the Bab al‑Mandeb and the Suez route — are a principal east–west conduit between South and East Asia, the Middle East, Africa and Europe. When several trunk cables that share this narrow corridor are damaged at once, the shortest, lowest‑latency routes vanish and traffic is forced onto longer, often already‑congested detours.
Pakistan’s internet ecosystem depends significantly on those east–west links for international capacity. Major trunk systems that historically transit the Jeddah corridor — including SEA‑ME‑WE‑4 (SMW4) and IMEWE (India–Middle East–Western Europe) — serve as arteries for consumer browsing, content delivery, and cloud traffic. The operational geometry of those cables concentrates risk: a localized event around a few landing stations can ripple across an entire region.

What happened — timeline and immediate facts​

Early on 6 September, automated routing telemetry and independent monitors registered sudden BGP reconvergence, route flaps and spikes in round‑trip time for Asia↔Europe and Asia↔Middle East flows. National carriers and outage‑tracking groups observed degraded throughput and a spike in customer complaints in multiple countries. Microsoft published an Azure Service Health advisory warning that traffic traversing the Middle East "may experience increased latency" while engineers rerouted and rebalanced capacity.
Carrier bulletins and independent monitors repeatedly pointed to faults clustered near Jeddah, Saudi Arabia — a geography that aggregates multiple long‑haul systems — naming candidate systems such as SMW4 and IMEWE among those likely affected. Those identifications are operationally plausible given the landing geography and observed route changes, though operator‑level forensic confirmation typically follows later after fault‑location work and repair‑ship diagnostics.
The immediate mitigation steps preserved reachability for most networks: traffic was rerouted over alternate subsea systems, terrestrial detours, leased transit and CDN edge nodes. Those changes prevented wholesale service outages but produced higher latency, jitter and occasional packet loss for latency‑sensitive services — exactly the customer experience reports that emerged from Pakistan and neighbouring countries.

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Why a cable cut becomes a nationwide slowdown: the technical anatomy​

The path from a physical seafloor fault to a Pakistani user seeing slow web pages or choppy video is deterministic and worth unpacking for IT teams.

• Border Gateway Protocol (BGP) and carrier route control react to a lost path by withdrawing affected prefixes and re‑advertising alternatives. That causes traffic to shift to other next‑hops.
• Alternate paths are often geographically longer (adding propagation delay) and traverse more transit networks and IXPs (adding processing and possible queuing delay).
• If those alternate pipes were not provisioned for the sudden, large influx of re‑routed traffic, they experience congestion that leads to queuing delay, increased jitter and packet loss.
• Latency‑sensitive applications — VoIP, video conferencing, synchronous DB replication, and some trading systems — manifest performance issues first; bulk transfers degrade more gracefully but still slow down.

Cloud providers operate logically redundant fabrics that separate control‑plane and data‑plane routing where possible. That architecture often preserves management and provisioning APIs even while user‑visible performance suffers. This distinction explains why a provider can report "no platform‑wide outage" while customers experience meaningful application slowdown: the control plane remains reachable but the data paths are longer or congested.

The impact in Pakistan — users, carriers, and enterprises​

Pakistan experienced a spectrum of effects that varied by ISP, peering strategy, and path diversity.

• Consumer experience: Slower page loads, choppy streaming, and unreliable video calling were commonly reported during peak hours. Outage trackers showed spikes in complaints from Pakistani users in the immediate incident window.
• National carriers and ISPs: Pakistan Telecommunication Company Limited (PTCL) and other domestic operators publicly acknowledged reduced international capacity on affected systems and warned customers of potential slowdowns while alternative channels were provisioned. Networks that relied heavily on the Jeddah corridor felt the most pressure.
• Enterprises and cloud customers: Cross‑region API calls, multi‑region replication and backup windows lengthened. Organizations using Microsoft Azure for cross‑region workloads saw higher latency on paths that previously traversed the Middle East corridor. Sensitive workflows such as synchronous database replication and real‑time collaboration tools degraded first.

The practical consequence for enterprises in Pakistan was a scramble to validate exposure, throttle or reschedule large transfers, and harden retry/timeouts for latency‑sensitive operations until the physical path diversity was restored or temporary leased capacity was provisioned.

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Cloud operators and Azure: what was said and what it meant​

Microsoft’s messaging typified the cloud response playbook: issue a Service Health advisory, reroute traffic, monitor, and rebalance capacity while repairs are arranged. Microsoft explicitly framed the incident as a performance degradation for traffic that "previously traversed through the Middle East," distinguishing it from a global outage. That messaging is factual and operationally useful: it tells customers the problem is transit‑layer performance rather than internal compute or storage failures.
From an operational standpoint, Microsoft's mitigations included:

• Dynamic rerouting of cross‑continent flows away from the damaged Red Sea segments.
• Rebalancing traffic across remaining subsea systems and terrestrial detours.
• Leveraging CDN edge nodes and localized peering where possible to reduce data‑plane pressure.

Those steps reduce the risk of total service interruption but cannot erase the physics of time: rerouted packets generally travel farther and cross more networks, which materially raises round‑trip times for certain cross‑region operations.

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Causes and attribution — what we know and what we don’t​

Public reporting and initial monitoring data pointed to multiple simultaneous faults in the Red Sea corridor. Two broad families of causation often arise in such incidents:

• Accidental mechanical damage: the most common historical cause. Anchor drags, fishing gear, or accidental vessel groundings can sever or damage cable segments that lie in shallow or territorial waters.
• Intentional harm: the Red Sea has been an active theatre for maritime security incidents in recent years, and deliberate acts cannot be ruled out immediately. Forensic attribution for subsea cuts is technically complex, slow, and requires operator diagnostics and maritime investigation. Early media and monitoring commentary noted both possibilities but cautioned that definitive attribution was provisional pending cable owner reports.

Because immediate telemetry alone cannot prove intent, every attribution should be treated with caution. Industry practice is to await consortium bulletins and formal fault‑location reports before declaring cause. The reporting surrounding this incident repeatedly emphasised that precise break coordinates and the root cause were subject to later verification.

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Repair timelines and practical realities​

Repairing submarine cables is a maritime logistics operation that takes time. The repair sequence typically includes:

• Fault localization using distributed optical time‑domain reflectometry (OTDR) and other diagnostic tools.
• Scheduling and dispatching a specialized cable repair ship to the fault location.
• Mid‑sea splicing operations — cutting out damaged sections and joining new fibre pairs.
• Testing and re‑provisioning restored capacity into production routes.

Repair timelines vary with conditions and constraints: availability of repair vessels, sea state, weather, permissioning from coastal states, and safety in contested waters all influence how fast an operator can restore service. Operators warned that repairs could take days to weeks depending on circumstance. Meanwhile, carriers and cloud providers lease capacity, reweight routes and use CDN or satellite fallbacks to manage immediate demand.

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Immediate steps Pakistan organizations should take​

For IT leaders, networks teams and cloud architects operating in Pakistan, this episode is both a reminder and a call to action. Recommended tactical steps:

• Map physical transit exposure: Identify which services, applications and peering relationships rely on routes that transit the Red Sea/Jeddah corridor. Maintain an accurate inventory of providers and the primary submarine systems they use.
• Harden application resilience: Increase client and server timeouts where sensible, implement exponential backoff for retries, and prioritize idempotent operations to reduce cascading retries during periods of high latency.
• Use multi‑region and multi‑provider redundancy: Where possible, replicate critical services across regions that do not share the same submarine corridor, and negotiate multiple transit providers with different physical paths.
• Shift bulk transfers: Reschedule large backups, bulk data migrations and non‑urgent replication to off‑peak hours or alternative routings to reduce pressure on recovery links.
• Engage cloud and carrier partners: Ask providers for transparency on which submarine systems serve your traffic and the expected timeline for repairs or temporary capacity leases. Negotiate emergency capacity and SLAs that include recovery roles for such corridor events.
• Monitor actively: Subscribe to Azure Service Health and equivalent carrier status notifications and use independent network monitoring to detect BGP path changes and RTT increases early.

These steps are practical, low‑cost mitigations that reduce business risk while longer‑term infrastructure changes take time.

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Strategic and policy implications for Pakistan​

The Red Sea incident is not just a technical outage; it is a policy and investment question for governments and telcos.

• Diversify physical routes: Nationally and regionally, governments and carriers should incentivize or directly invest in additional fibre routes that avoid single chokepoints, including terrestrial backhaul, overland fibre through alternate neighbours, and new subsea projects with different landing zones.
• Improve repair readiness: Ensuring access to repair ships, faster permissioning for repairs in territorial waters, and cooperative regional frameworks can shorten repair windows. Coordination between maritime authorities, telcos and consortium owners matters.
• Hardening and legal protections: As submarine infrastructure becomes more strategically important, governments must weigh legal protections, monitoring and deterrence against intentional interference with communications infrastructure.
• Public transparency and provider accountability: Carriers and cloud providers should provide clearer documentation on which physical routes underpin their transit offerings. Greater transparency enables enterprises and governments to make resilience choices rooted in physical geography rather than marketing alone.

For Pakistan, where digital services and cloud adoption continue to accelerate, those policy levers matter for economic resilience.

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Strengths and weaknesses of the response so far — critical analysis​

Strengths

• Operators and cloud providers acted quickly to preserve reachability. The rapid issuance of Azure advisories and carrier bulletins gave customers actionable intelligence and avoided panic. Dynamic rerouting and temporary capacity leases are standard operational mitigations that preserved basic connectivity.
• Independent monitoring groups (NetBlocks and others) provided near‑real‑time telemetry that corroborated carrier and cloud advisories, giving enterprises early warning to take tactical steps.

Weaknesses and risks

• Physical route concentration remains the elephant in the room. Logical redundancy in cloud architectures does not replace physical route diversity; multiple high‑capacity links sharing the same narrow corridor create correlated failure risk. The incident demonstrated that logic‑level resilience can be overwhelmed by correlated physical faults.
• Transparency gaps persist. Precise fault attributions and exact cable break coordinates often lag, which complicates both public understanding and commercial decision‑making. Early public lists of implicated cables are useful but remain provisional until consortium diagnostics are published. That uncertainty complicates root‑cause analysis and policy responses.
• Repair delays and geopolitical constraints can extend impact. If repairs are delayed due to vessel availability, permissioning or security concerns, the performance and economic impacts can last far beyond the immediate incident window.

Cautionary note: attributions of cause (accidental vs deliberate) were widely discussed in reporting but were provisional in the early days of the event; treat any definitive cause claims made before consortium confirmation with caution.

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Longer‑term technical recommendations​

For ISPs, cloud customers and national planners looking to reduce the odds that a single corridor event will cause systemic slowdowns:

• Build true physical diversity: Negotiate cross‑provider transit that intentionally uses distinct submarine systems and overland routes. Beware providers that advertise "diversity" but still route through a common undersea corridor.
• Design for degraded performance: Architect distributed systems to survive higher RTT and jitter for periods — e.g., relaxed consistency modes, asynchronous replication, and progressive degradation strategies for real‑time features.
• Contractual SLAs that include contingency: Negotiate terms that include emergency capacity options, predictable transparency on physical routing, and penalties or credits when provider failures exceed agreed resilience levels.
• Invest in active monitoring: Use BGP monitoring, RTT measurement and synthetic transactions across multiple geographic endpoints to detect path anomalies early and verify rerouting behavior.
• Engage in public‑private planning: Work with regulators to prioritise submarine cable protection, streamlined repair‑ship access and regional contingency planning.

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What readers in Pakistan should expect next​

• Short term: Expect intermittent higher latency and localized slowdowns on cross‑region traffic while carriers and cloud providers rebalance capacity and lease alternatives. Cloud control planes and many regional services will likely remain reachable even if performance for cross‑region flows remains degraded.
• Medium term: Repairs will proceed according to maritime availability and security conditions; timelines can span days to weeks. Once repair ships locate and fix damaged segments, normal low‑latency routes will progressively restore.
• Long term: The incident should accelerate investments in diversified routes, greater transparency from providers and stronger contingency planning by enterprises that rely on low‑latency cross‑continent paths.

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Conclusion​

The Pakistan internet slowdown was not a mysterious software glitch or an isolated local outage — it was the predictable, if painful, consequence of multiple subsea fibre faults in a narrow maritime corridor that funnels a disproportionate share of east–west traffic. Cloud and carrier mitigations preserved reachability, but the physics of rerouting and limited alternative capacity produced the higher latency and user‑visible slowdowns Pakistani businesses and consumers experienced.
For enterprises and IT teams in Pakistan the near‑term priorities are tactical and clear: map exposure, harden applications for higher latency, schedule bulk transfers away from peak windows, and press cloud and transit providers for transparency on the physical routes that underpin critical services. For policymakers and carriers the event underlines a strategic imperative: invest in real route diversity, speed repairs and strengthen protections for submarine infrastructure so that a single corridor event cannot degrade a national digital economy.
The incident is a practical reminder that the internet's resilience is as much about ships, splices and seabed mapping as it is about virtual redundancy and software design — and that durable digital resilience requires aligning both.

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Source: TechJuice https://www.techjuice.pk/pakistans-internet-slowdown-explained/amp/