Multiple products in us-central1-b are experiencing network service degradation.

Lesson: Teams should check service health dashboards when regional network service degradation affects cloud products.

What happened

Incident Report Summary On Tuesday, 1 September 2026, some customers in us-central1 experienced network service degradation and instance isolation for a duration of 4 hours and 11 minutes. To our customers whose businesses were impacted during this disruption, we sincerely apologize. This is not the level of quality and reliability we strive to offer you, and we are taking immediate steps to improve the platform’s performance and availability. Root Cause The event was triggered by the inadvertent physical disconnection of network fiber-optic cables during routine hardware maintenance. A technician was performing a scheduled capacity upgrade on data center routers that support a fraction of capacity in the us-central1-b zone and a small fraction of capacity in the us-central1-f zone. During the hands-on maintenance, optical fibers connecting the data center routers to the network fabric were unplugged and the optical transceivers were replaced with a transceiver that supports higher-density connectivity. This transceiver was not compatible with the transceivers still in place in the data center fabric, causing a loss of connectivity for each fiber. The network is designed with redun

1. available · Sep 10, 21:20 UTC
   Incident Report Summary On Tuesday, 1 September 2026, some customers in us-central1 experienced network service degradation and instance isolation for a duration of 4 hours and 11 minutes. To our customers whose businesses were impacted during this disruption, we sincerely apologize. This is not the level of quality and reliability we strive to offer you, and we are taking immediate steps to improve the platform’s performance and availability. Root Cause The event was triggered by the inadvertent physical disconnection of network fiber-optic cables during routine hardware maintenance. A technician was performing a scheduled capacity upgrade on data center routers that support a fraction of capacity in the us-central1-b zone and a small fraction of capacity in the us-central1-f zone. During the hands-on maintenance, optical fibers connecting the data center routers to the network fabric were unplugged and the optical transceivers were replaced with a transceiver that supports higher-density connectivity. This transceiver was not compatible with the transceivers still in place in the data center fabric, causing a loss of connectivity for each fiber. The network is designed with redundant routers in separate data center rooms within the same building so that failure of one router does not interrupt service. The maintenance was intended to upgrade one router at a time over several days, with traffic diversions at each step and verification between steps that the network has retur
2. available · Sep 3, 17:47 UTC
   Preliminary Incident Report We sincerely apologize for the disruption this incident caused to your business. We know how much you rely on Google Cloud, and we regret the impact on your environment. We are working to address the root cause and prevent this from occurring in the future. Please note, this information is based on our best knowledge at the time of posting and is subject to change as our investigation continues. A final Incident Report with preventative actions will be posted once our investigation is complete. If you have experienced impact outside of what is listed below, please reach out to Google Cloud Support using https://cloud.google.com/support Date/Time of the Issue (All time US/Pacific) **Incident Start**: 1 September 2026 07:41 **Incident End**: 1 September 2026 11:52 **Duration**: 4 hours, 11 minutes Summary On Tuesday, 1 September 2026, some customers in us-central1-b experienced network service degradation and instance isolation for a duration of 4 hours and 11 minutes. To our customers whose businesses were impacted during this disruption, we sincerely apologize. This is not the level of quality and reliability we strive to offer you, and we are taking immediate steps to improve the platform’s performance and availability. Preliminary Root Cause The immediate technical trigger for this event was the inadvertent physical disconnection of network fiber-optic cables during a routine hardware maintenance procedure. An engineer was performing a scheduled
3. service_disruption · Sep 1, 19:12 UTC
   **Summary** Multiple products in us-central1-b experienced network service degradation. **Description** The issue was affecting a portion of the us-central1-b zone. The remaining zones in the region were unaffected. All the impacted products have recovered. From preliminary analysis, routine network fabric path maintenance triggered unexpected issues in one cluster in us-central1-b. We have recovered the network capacity that was impacted and restored all zonal and regional services. Maintenance in the region has been halted while proactive audits are carried out. We thank you for your patience while we worked on resolving the issue. **Customer Symptoms** Customers experienced elevated packet loss and errors. **Workaround** The issue has been mitigated.
4. service_disruption · Sep 1, 18:36 UTC
   **Summary** Multiple products in us-central1-b are experiencing network service degradation. **Description** The issue is affecting a portion of the us-central1-b zone. The remaining zones in the region are unaffected. Most of the products have recovered. The impacted products Cloud Run and App Engine are also seeing recovery and the errors have lowered pre-incident levels. Engineering continues to monitor and validate. Routine network fabric path maintenance triggered unexpected issues in two clusters in us-central1-b. We have recovered the network capacity that was impacted and restored all zonal and regional services. Maintenance in the region has been halted while proactive audits are carried out. We will provide more information by Tuesday, 2026-09-01 12:30 US/Pacific with current details. **Customer Symptoms** Customers are experiencing elevated packet loss and errors. * Cloud Run * App Engine Following products have recovered * BigQuery * Cloud Dataflow * Cloud Bigtable * Compute Engine * Cloud Hybrid Connectivity * Cloud Filestore * Virtual Private Cloud * Cloud Spanner * Google Kubernetes Engine * Cloud SQL * AlloyDBCloud VPN * Apigee * Cloud Interconnect * Cloud NAT * Looker (Google Cloud core) * Google SecOps SOAR * Cloud Firestore **Workaround** * Customers with service layer retries may see successful completions as only a portion of the zone is affected.
5. service_disruption · Sep 1, 18:01 UTC
   **Summary** Multiple products in us-central1-b are experiencing network service degradation. **Description** The issue is affecting a portion of the us-central1-b zone. The remaining zones in the region are unaffected. Most of the products have recovered and the engineering team is still validating a few remaining product impacts. Routine network maintenance triggered issues in us-central1-b. We have recovered the network capacity that was impacted and restored all zonal and regional services. Maintenance in the region has been halted while proactive audits are carried out. We will provide more information by Tuesday, 2026-09-01 12:30 US/Pacific with current details. **Customer Symptoms** Customers are experiencing elevated packet loss and errors. * Cloud Run * App Engine Following products have recovered * BigQuery * Cloud Dataflow * Cloud Bigtable * Compute Engine * Cloud Hybrid Connectivity * Cloud Filestore * Virtual Private Cloud * Cloud Spanner * Google Kubernetes Engine * Cloud SQL * AlloyDBCloud VPN * Apigee * Cloud Interconnect * Cloud NAT * Looker (Google Cloud core) * Google SecOps SOAR * Cloud Firestore **Workaround** * Customers with service layer retries may see successful completions as only a portion of the zone is affected.
6. service_disruption · Sep 1, 17:09 UTC
   **Summary** Multiple products in us-central1-b are experiencing network service degradation. **Description** The issue is affecting a portion of the us-central1-b zone. The remaining zones in the region are unaffected. Most of the products have recovered and the engineering team is still validating a few remaining product impacts. We will provide more information by Tuesday, 2026-09-01 11:00 US/Pacific with current details. **Customer Symptoms** Customers are experiencing elevated packet loss and errors. * Cloud Run * App Engine Following products have recovered * BigQuery * Cloud Dataflow * Cloud Bigtable * Compute Engine * Cloud Hybrid Connectivity * Cloud Filestore * Virtual Private Cloud * Cloud Spanner * Google Kubernetes Engine * Cloud SQL * AlloyDBCloud VPN * Apigee * Cloud Interconnect * Cloud NAT * Looker (Google Cloud core) * Google SecOps SOAR * Cloud Firestore **Workaround** * Customers with service layer retries may see successful completions as only a portion of the zone is affected. * Customers that are severely affected and have services available in alternate zones can failover to alternate zones.
7. service_disruption · Sep 1, 16:19 UTC
   **Summary** Multiple products in us-central1-b are experiencing network service degradation. **Description** The issue is affecting a portion of the us-central1-b zone. The remaining zones in the region are unaffected. Following network-level mitigation efforts, the underlying network infrastructure has fully recovered. Product engineering teams across Cloud are currently validating the recovery status of individual services. We will provide more information by Tuesday, 2026-09-01 10:00 US/Pacific with current details. **Customer Symptoms** Customers are experiencing elevated packet loss and errors. * BigQuery * Cloud Dataflow * Cloud SQL * App Engine * Cloud Run * AlloyDB * Cloud Bigtable * Cloud Spanner * Compute Engine * Cloud VPN * Cloud Interconnect * Cloud NAT * Cloud Filestore * Cloud Hybrid Connectivity * Virtual Private Cloud * Google Kubernetes Engine * Looker (Google Cloud core) * Apigee * Google SecOps SOAR **Workaround** * Customers with service layer retries may see successful completions as only a portion of the zone is affected. * Customers that are severely affected and have services available in alternate zones can failover to alternate zones.
8. service_disruption · Sep 1, 16:03 UTC
   **Summary** Multiple products in us-central1-b are experiencing network service degradation.  **Description** We are experiencing a networking issue starting Tuesday, 2026-09-01 07:41 US/Pacific. The issue is affecting a portion of the us-central1-b zone. The remaining zones in the region are unaffected. Our network engineering team has put in mitigations and we are seeing services starting to recover. We will provide more information by Tuesday, 2026-09-01 09:30 US/Pacific with current details. We apologize to all who are affected by the disruption. **Customer Symptoms** Customers are experiencing elevated packet loss and errors. * BigQuery * Cloud Dataflow * Cloud SQL * App Engine * Cloud Run * AlloyDB * Cloud Bigtable * Cloud Spanner * Compute Engine * Cloud VPN * Cloud Interconnect * Cloud NAT * Cloud Filestore * Cloud Hybrid Connectivity * Virtual Private Cloud * Google Kubernetes Engine * Looker (Google Cloud core) **Workaround** * Customers with service layer retries may see successful completions as only a portion of the zone is affected. * Customers that are severely affected and have services available in alternate zones can failover to alternate zones.