Point your Paxeer chain node at an Autobahn config file and the classic CometBFT mempool, block executor and consensus state never load. Your validator disseminates transaction payloads on its own lane while agreement runs separately, and it sequences senders in the address shard it owns, in strict nonce order. Transactions for other shards proxy to that shard owner's EVM RPC. Observer nodes and remote signers are not yet supported.

What it does

Setting the autobahn-config-file option on a Paxeer chain node replaces the classic CometBFT path entirely: the classic mempool, block executor, write-ahead log and consensus state are never constructed. In their place runs an Autobahn-style protocol that separates data dissemination from agreement, with per-validator lanes carrying lane proposals and lane quorum certificates, and a separate agreement path carrying app proposals, prepare, commit, app and timeout quorum certificates. Each validator owns a deterministic shard of EVM address space and sequences transactions from senders in that shard in strict nonce order. A node that receives a transaction for an address outside its own shard proxies it to the shard owner's EVM RPC endpoint.

Key capabilities

• Per-validator data lanes disseminate transaction payloads independently of the agreement path.
• Deterministic address sharding assigns every sender to one sequencing validator.
• Nodes proxy transactions to the shard owner's EVM RPC instead of gossiping them.
• Transaction broadcast RPC routes to the Autobahn mempool rather than classic CheckTx.
• Leader and shard selection derive from a committee domain hash, weighted by validator weight.
• Consensus safety state is written to disk by default, refusing configs that would discard it.

Differentiators

Sender-address sharding with EVM RPC proxying to the shard owner, rather than network-wide transaction gossip. The classic consensus path is replaced wholesale by one config file, not layered on top of it. A missing persistence directory is a hard startup error, as an explicit equivocation guard, and disabling persistence requires setting unsafe_test_only_disable_persistence.

Outcomes

• Your validator ships transactions without waiting for a leader to disseminate them.
• Two validators never compete to sequence the same account.
• One config file switches the path on; deprecated timeout keys are rejected.

Technical notes

• Configured defaults from the gen-autobahn-config generator: block_interval 400 ms (the delay after which a non-full block may be produced), view_timeout 1500 ms, dial_interval 10 s, allow_empty_blocks true, persistent_state_dir data/autobahn.
• The generator writes max_txs_per_block 5000, but the producer clamps it to the hard cap MaxTxsPerBlock of 2000, so the shipped default has no effect. Total transaction bytes per block are capped at 2000 × 1024.
• Lane depth is hard-coded at 30 blocks (3 × BlocksPerLanePerCommit) and is not configurable.
• Fault tolerance is 3f < N; the commit and app quorums are the total weight minus that faulty weight.
• Not yet implemented: observer (non-validating) nodes are refused, so an Autobahn network runs validators only, and a remote validator signer is rejected because a local key is required.
• Shard assignment carries an unresolved censorship-resistance issue recorded in the code: shards are currently sized for equal load on a private testnet, and the comment states that mainnet needs a different resolution.
• The classic timeout-propose, timeout-commit and skip-timeout-commit config keys are rejected as deprecated. max_txs_per_second exists but is marked test-only.

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