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1. IL-0358 Packet Public Cloud locations had high latency and unreachable paths from routing loops and blackholed traffic

   Packet2019

   Symptoms

   At about 08:49 UTC on 2 June 2019, Packet's internal network monitoring alerted on serious reachability and performance problems in several of Packet's global datacenter locations. The first investigation found routing loops and traffic being blackholed to specific internal and Internet destinations.

   Network unreachablePacket lossHigh latency

   Trigger

   A trans-continental US backbone link in the network of Packet's upstream provider Zayo had a hardware failure and blackholed IP traffic routed over it.

   Root cause

   Dependency failure

   Component

   Backbone network (WAN)BGP routingNetwork control plane (SDN)

   Contributing factor

   –

   Detection

   Packet's internal network monitoring alerted at 08:49 UTC on reachability issues in several global datacenter locations, and engineers confirmed them at 08:52.

   Remediation

   • Migrated traffic to an alternative network and removed Zayo from the provider mix
   • Applied route filters to return service to normal
   • Optimised specific routing policies to improve latency across the backbone with the new traffic mix

   Action items

   • Expand internal connectivity monitoring and alerting of on-call operations teams
   • Expand network automation and routing so traffic can be balanced across all available backbone paths and an operator can trigger automated re-routes across all Packet datacenters in a major provider incident
   • Make Packet's provisioning systems less dependent on third party network providers and inter-datacenter connectivity

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