# FIX Protocol Session Layer Specification (FIXT.1.1)

> Bi-directional, stateful session communication protocol providing guaranteed, ordered message delivery for financial transactions.

Canonical: https://terminalledgerdesk.com/engines/fix-session-layer-specification
Last updated: 2026-10-23T23:41:50.410Z

## FIX Protocol Session Layer Specification (FIXT.1.1) (FIXT-SESSION)

- Type: product
- Jurisdiction: International (FIX Trading Community)
- Regulatory body: FIX Protocol Session Layer Specification (FIXT.1.1)
- Wikidata: Not supplied

Bi-directional, stateful session communication protocol providing guaranteed, ordered message delivery for financial transactions.

### Recorded metadata

| Field | Value |
| --- | --- |
| category | Order Gateway Protocols |
| coverageDesk | Terminal Ledger Desk |
| regulatoryBody | FIX Protocol Session Layer Specification (FIXT.1.1) |
### Related research

- [FIX Engine Session Resilience: Managing Sequence Number Resets, Gap Fills, and Heartbeat Timeouts](https://terminalledgerdesk.com/reports/fix-engine-session-management-heartbeats-sequence-resets-and-gap-fills) — Order Gateway Protocols. How institutional trading gateways recover from network drops without losing execution reports or creating duplicate order submissions under FIX session rules.
- [Order Book L3 Market Data Feed — Operational Runbook Excerpt: 2026 Institutional Audit & Desk Controls](https://terminalledgerdesk.com/reports/order-book-l3-market-data-feed-operational-runbook-excerpt-015) — Order Gateway Protocols. 2026 institutional desk audit of order book l3 market data feed focusing on operational runbook excerpt. Covers statutory register tie-out (FIXT-SESSION), 12.0 bps quantitative benchmarks, mathematical calibration, and compliance verification workflows.
- [Market Data Entitlement Throttling — Failover Drill Checklist: 2026 Institutional Audit & Desk Controls](https://terminalledgerdesk.com/reports/market-data-entitlement-throttling-failover-drill-checklist-063) — Order Gateway Protocols. 2026 institutional desk audit of market data entitlement throttling focusing on failover drill checklist. Covers statutory register tie-out (FIXT-SESSION), 13.0 bps quantitative benchmarks, mathematical calibration, and compliance verification workflows.