> ## Documentation Index
> Fetch the complete documentation index at: https://docs.lerian.studio/llms.txt
> Use this file to discover all available pages before exploring further.

# SILOC ingress routing contract

> SILOC documentation now defines its closed SFN routing policy, failure handling, and relay deduplication boundary.

<Badge stroke icon="calendar-days" iconType="regular">August 18, 2026</Badge> <Badge stroke icon="file-code" iconType="regular">Documentation correction</Badge> <Badge color="red" size="lg" stroke icon="triangle-exclamation" iconType="regular">Action required</Badge>

## Affects

***

Teams that operate Lerian SILOC SFN ingestion or consume its settlement-funding relay.

## What changed

***

SILOC applies a closed `CodProdt` and `CodMsg` routing policy. `PAG0101` defers participant status for both OT and SLC. `PAG0102`, `LDL0021`, and `PAG0103` defer for OT and relay to Lerian SLC. `LDL0020`, `LDL0006`, and every unsupported pair fail closed to an operator exception and are never relayed as settlement funding.

SLC relay is at-least-once. For a successfully decoded funding frame with a nonblank `BCMSG.NUOp`, the service checks durable deduplication before relay and writes the processed-message record only after a successful relay.

This is a documentation correction that aligns with the implemented contract. It does not announce a runtime release.

## Impact

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**Classification: Action required.** Operators and downstream consumers that expect the former supported-message set or composite deduplication key can route or reconcile settlement messages incorrectly.

## What you need to do

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<Steps>
  <Step>Update SFN operating runbooks to treat unsupported product-message pairs as operator exceptions.</Step>
  <Step>Do not classify `LDL0020` or `LDL0006` as settlement-funding relays.</Step>
  <Step>Review relay reconciliation for at-least-once delivery and `BCMSG.NUOp` deduplication.</Step>
</Steps>

### Deadline

Complete the review before the next SILOC SFN ingestion change.

## Resources

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* [How SILOC works](/en/rails/siloc/how-siloc-works)
* [Operate SILOC](/en/rails/siloc/siloc-operations)