Speaker
Description
With Comcast vCMTS Edge Compute providing internet services to tens of millions of broadband access subscribers, work is underway to move DNS Service to locations significantly closer to Comcast subscribers for lower latency and smaller blast-radii. This presentation describes Comcast’s architecture for deploying DNS caching services in the vCMTS Edge Compute environment while preserving existing customer-facing anycast addresses and operational models. Rather than relocating recursive resolution, the initial design places DNS caches at the edge and retains centralized resolvers, allowing subscriber traffic to benefit from reduced latency while minimizing risk and migration complexity.
The session will cover the routing and used to advertise Do53 and DoH anycast services directly from edge locations, including health-monitored route injection, automated failure handling, and operational controls that allow selective participation in the anycast service. We will examine how encrypted DNS (DoH) was integrated into the platform using a dual-anycast IP approach and static service dependencies that eliminate traditional GSLB requirements while coupling service availability to the local DNS cache failure domain.
Attendees will also get an in-depth look at the implementation details behind running high-performance DNS workloads in Kubernetes-based edge environments. Topics include design tradeoffs between pod-level and cluster-level service models, reasons for avoiding traditional load-balancer approaches, the use of SR-IOV to steer anycast traffic directly into dedicated DNS cache workloads, health-monitoring and route-control mechanisms, deployment automation, and the telemetry and alarming systems used to operate DNS at hundreds of distributed edge locations. The presentation concludes with lessons learned from bringing one of the Internet’s largest ISP DNS services closer to subscribers while preserving reliability, operational simplicity, and existing customer configurations.
| Talk duration | 20 Minutes (+5 for Q&A) |
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