Network update: sprints 100 & 101

Author: coot

blog/2025-11-25-network.md

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+---
+title: Network Team Update
+slug: 2025-10-24-network
+authors: [coot]
+tags: [network]
+hide_table_of_contents: false
+---
+
+## Overview of spint [100][sprint-100] and [101][sprint-101]
+
+### Cardano Incident
+
+On November 12th, Cardano experienced a fork due to a bug in ledger
+(de-)serialisation.  Some nodes accepted an invalid tx, while others rejected
+it, leading to a fork of the chain.
+
+The network team worked closely with the other Cadano teams, Intersect, Cardano
+Foundation, Emurgo, and stake pool operators to monitor and resolve the
+incident.
+
+The network layer was not affected by the incident, and its resiliency played
+a role in the recovery of the network.  We identified some areas that can
+further improve the network layer's robustness in such situations, and we'll be
+working on addressing these issues.
+
+### Churn Mitigation
+
+We rolled out a churn mitigation included in the latest `cardano-node-10.5` and
+`10.6` releases.  This change ensures the speed of churn of hot peers is at
+least the speed of churn for established peers, and the speed of churn of the
+established peers is at least the speed of churn of known peers.   This way, we
+avoid a situation where, over a long period of time, established peers will
+accumulate already tried hot peers, and cold peers will accumulate already
+tried established peers.  See [#5238] for more details.
+
+The issue was identified using [CF]'s __[cardano-ignite]__ tool, with analysis
+provided by [Karl Knutsson].
+
+### DMQ-Node
+
+We are initiating a public repository for `dmq-node` to host its codebase.
+
+We removed the KES evolution configuration; as a consequence, the genesis file
+option is no longer needed in the configuration of `dmq-node`, see [#5244].
+
+### Peer Selection Improvements
+
+Refined peer selection for local root peers behind firewalls: instead of
+polling, it now waits for incoming connections and reuses them outbound. See
+[#5241] for details.
+
+
+[sprint-100]: https://github.com/orgs/IntersectMBO/projects/5/views/1?filterQuery=sprint%3A%22Sprint+100%22
+[sprint-101]: https://github.com/orgs/IntersectMBO/projects/5/views/1?filterQuery=sprint%3A%22Sprint+101%22
+
+[#5238]: https://github.com/IntersectMBO/ouroboros-network/pull/5238
+[#5241]: https://github.com/IntersectMBO/ouroboros-network/pull/5241
+[#5244]: https://github.com/IntersectMBO/ouroboros-network/pull/5244
+
+[CF]: https://cardanofoundation.org/
+[cardano-ignite]: https://github.com/cardano-foundation/cardano-ignite
+[Karl Knutsson]: https://github.com/karknu