docs: update high-level-view.md with socket mode architecture (#69355)

Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Co-authored-by: [email protected] <[email protected]>

Author: devin-ai-integration[bot]

docs/platform/understanding-airbyte/high-level-view.md

@@ -10,7 +10,36 @@ The platform provides all the horizontal services required to configure and run
 
 Connectors are independent modules which push/pull data to/from sources and destinations. Connectors are built in accordance with the [Airbyte Specification](./airbyte-protocol.md), which describes the interface with which data can be moved between a source and a destination using Airbyte. Connectors are packaged as Docker images, which allows total flexibility over the technologies used to implement them.
 
-A more concrete diagram can be seen below:
+## Data Transfer Modes
+
+Airbyte supports two data transfer modes that are automatically selected based on connector capabilities:
+
+- **Socket Mode**: Records flow directly from source to destination via Unix domain sockets, enabling high-throughput parallel data transfer. A lightweight bookkeeper process handles control messages, state, and logs.
+- **Legacy Mode**: Records flow through an orchestrator middleware that sits between source and destination, using standard input/output streams.
+
+Socket mode is used when both source and destination connectors support it, providing significantly higher performance for data movement operations.
+
+### Data Flow Comparison
+
+```mermaid
+---
+title: Data Transfer Modes
+---
+flowchart LR
+    subgraph Legacy["Legacy Mode"]
+        SRC1[Source] --> ORCH[Orchestrator] --> DEST1[Destination]
+    end
+    
+    subgraph Socket["Socket Mode"]
+        SRC2[Source] -.->|control| BK[Bookkeeper]
+        SRC2 ==>|records via sockets| DEST2[Destination]
+        DEST2 -.->|state| BK
+    end
+```
+
+## Platform Architecture
+
+A more concrete diagram of the platform orchestration can be seen below:
 
 ```mermaid
 ---
@@ -45,6 +74,13 @@ flowchart LR
 - **Workload API** [`airbyte-workload-api-server`]: The HTTP interface for enqueuing workloads — the discrete pods that run the connector operations.
 - **Launcher** [`airbyte-workload-launcher`]: Consumes events from the workload API and interfaces with k8s to launch workloads.
 
+### Data Transfer Middleware
+
+Within connector operation pods, Airbyte runs middleware containers to process connector output:
+
+- **Bookkeeper** [`airbyte-bookkeeper`]: Used in socket mode. Processes control messages, state, and logs while records flow directly between connectors via sockets.
+- **Container Orchestrator** [`airbyte-container-orchestrator`]: Used in legacy mode. Sits between source and destination connectors, processing all data and control messages.
+
 The diagram shows the steady-state operation of Airbyte, there are components not described you'll see in your deployment:
 
 - **Cron** [`airbyte-cron`]: Clean the server and sync logs (when using local logs). Regularly updates connector definitions and sweeps old workloads ensuring eventual consenus.