High Packet Loss on Cogent Routes Between US and Singapore

On September 30, 2025, multiple monitoring probes observed significant packet loss on Cogent routes connecting the United States and Singapore.

The traceroute analysis revealed that traffic was routed through several Cogent core routers across Washington D.C., Atlanta, Dallas, Seattle, San Francisco, Los Angeles, and then extended to Singapore (SIN01).

However, packet loss rates along the path were abnormally high, often between 40% and 70%, severely degrading end-to-end connectivity and service quality.

The issue appears concentrated on Cogent’s backbone network, especially at nodes in San Jose (SJC13) and Singapore (SIN01), where loss exceeded 55%.

Such disruptions would likely impact latency-sensitive applications such as financial services, video conferencing, and cloud-based workloads between North America and Southeast Asia.