Cases2 cases

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1. IL-0564 Linode's Miami, Milan and Sao Paulo data centers had packet loss as traffic moved onto congested alternate paths

   Linode2025

   Symptoms

   Customers using Linode's US-MIA (Miami) and IT-MIL (Milan) data centers saw packet loss and brief performance problems on 14 September 2025 from 17:42 to 18:43 UTC. BR-GRU (Sao Paulo) had the same packet loss on 15 September 2025 from 01:44 to 04:22 UTC.

   Packet loss

   Trigger

   A gradual increase in prefixes pushed the routing between the core router and the edge router past the maximum number of permitted prefixes.

   Root cause

   Capacity exhaustion

   Component

   BGP routingBackbone network (WAN)

   Contributing factor

   –

   Remediation

   • Raised the prefix limit on all the data center routers

   Action items

   • Raise the thresholds of the sessions between Akamai's backbone and the data center ECOR routers
   • Improve the existing alerting and check its severity before limits are reached, with escalation to the right team for immediate action

   View case
2. IL-0341 Traffic between Cloudflare and AWS us-east-1 had high latency, packet loss and origin failures for almost four hours

   Cloudflare2025

   Symptoms

   From 16:27 UTC on 21 August 2025, users connecting to Cloudflare from servers in AWS us-east-1, or receiving connections from Cloudflare there, saw high latency, packet loss and failures to reach origins. Cloudflare's network team was alerted to internal congestion in Ashburn (IAD) at 16:44 UTC.

   Packet lossHigh latencyIntermittent timeouts

   Trigger

   At about 16:27 UTC a single customer began sending many requests from AWS us-east-1 to Cloudflare for objects in Cloudflare's cache, doubling the total traffic from Cloudflare to AWS.

   Root cause

   Capacity exhaustion

   Component

   Transit gateway or network interconnectBGP routingCDN and edge network

   Contributing factor

   No headroomHarmful manual actionExcessive blast radius

   Detection

   Cloudflare's network team was alerted to internal congestion in Ashburn (IAD) at 16:44 UTC, and an incident was raised for customer impact at 17:45 UTC.

   Remediation

   • Rate limited the single customer whose traffic caused the surge
   • Took further traffic engineering actions that fully resolved the congestion
   • Asked AWS to revert its BGP prefix withdrawals, which AWS finished at 20:07 UTC

   Action items

   • Build a mechanism to deprioritise a customer's traffic when it congests the network enough to affect others
   • Speed up the Data Center Interconnect upgrades to add network capacity
   • Work with AWS so the two companies' BGP traffic engineering actions do not conflict
   • Build a traffic management system that gives each customer a network resource budget and automates the manual actions used here

   Lessons

   Cloudflare concludes that it must isolate customers better so that no single customer can take over shared network resources and degrade the platform for others, and that its network needs enough capacity to meet demand. It describes the outage as the result of insufficient network congestion management during an unusual high-traffic event.

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