# HN825: Faster Than Dijkstra? Exploring a New Shortest-Path Algorithm with Bruce Davie

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Text version: https://stenobird.com/podcast/heavy-networking/hn825-faster-than-dijkstra-exploring-a-new-shortest-path-algorithm-with-bruce-davie.md
Podcast: [Heavy Networking](https://stenobird.com/podcast/heavy-networking)
Published: 2026-05-01T18:23:29+00:00
Episode link: https://packetpushers.net/podcasts/heavy-networking/hn825-faster-than-dijkstra-exploring-a-new-shortest-path-algorithm-with-bruce-davie/
Audio file: https://feeds.packetpushers.net/link/12486/17330395/HN825.mp3
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JSON: https://stenobird.com/v1/public/podcasts/heavy-networking/episodes/hn825-faster-than-dijkstra-exploring-a-new-shortest-path-algorithm-with-bruce-davie
Duration seconds: 3283

## Resource

Dr. Bruce Davie evaluates whether a new, theoretically faster shortest-path algorithm can realistically replace Dijkstra's algorithm in modern routing. The discussion explores why algorithmic complexity matters less than the systemic delays in failure detection and propagation.

## Highlights
- Main idea: Theoretical algorithmic improvements often fail to impact real-world performance due to the overhead of failure detection and packet propagation
- Practical takeaway: Optimizing the SPF calculation is less impactful than reducing the time it takes to detect a link failure and propagate link-state advertisements
- Failure mode: Implementing overly complex algorithms increases the risk of unhandled corner cases and implementation bugs in production routers
- Systemic view: Network convergence is a multi-stage process involving physical layer detection, BFD, LSA flooding, and hardware forwarding table updates
- Lesson: When evaluating new technologies, determine if the 'juice is worth the squeeze' by looking at the entire system rather than isolated metrics

## Topics

Dijkstra's Algorithm, Link State Routing, Network Convergence, MPLS, BFD, Network Engineering, Algorithm Complexity, Systems Approach

## Chapters
- 1:00 — Introduction to Dr. Bruce Davie: Dr. Bruce Davie discusses his background in networking, including his work on MPLS at Cisco and his current role at Systems Approach.
- 5:00 — The Hacker News Debate: A look at the reaction to new shortest-path research and the challenges of presenting complex algorithmic shifts to the community.
- 9:05 — The Mechanics of Link State Routing: An explanation of how routers calculate the lowest cost path based on throughput and link state packets.
- 13:20 — The SPF Calculation Process: A deep dive into the tentative and confirmed lists used during the Shortest Path First (SPF) calculation process.
- 17:40 — The Risks of Algorithmic Complexity: Discussing why simple, proven algorithms like Dijkstra's are preferred over complex alternatives to avoid implementation errors.
- 25:55 — The Bottleneck: Failure Detection: Why fast failure detection (like BFD) is more critical to convergence than the speed of the underlying path algorithm.
- 38:30 — Evaluating New Algorithms: Comparing the theoretical benefits of new research against the practical realities of modern router hardware and software.

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## Transcript

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