I. Overview

%%{init: { 'theme': 'base', 'themeVariables': { 'edgeLabelBackground': '#fff' }}}%%
flowchart LR
    A["Single, unified\nnetwork"] -- "Physical / logical isolation" --> B["Internet threats\nblocked"]
    style A fill:#f9f9f9,stroke:#333,stroke-width:3px
    style B fill:#e1f5fe,stroke:#01579b,stroke-width:3px

Definition: A collective term for network separation, which isolates the internal business network from the external internet to block outside attacks, and network integration, which ensures the safe movement of data between the separated networks.

Features:
( APT Response ) Protects internal network assets from Advanced Persistent Threats ( APT ) and blocks the spread of an attack.
( Data Leak Prevention ) Isolates the outbound path for sensitive information and personal data at the source.
( Compliance ) Satisfies requirements of the Network Act, the Personal Information Protection Act, and ISMS-P certification.

II. Mechanism & Components

Physical vs. Logical Network Separation

CategoryPhysical SeparationLogical Separation
ImplementationUses two physical PCs (physical isolation)Uses server/desktop virtualization ( VDI )
Security LevelHighest (physically separate circuits)Relatively lower (virtualization vulnerabilities exist)
Build CostHigh (hardware procurement and circuit installation)Moderate (centered on software and server infrastructure)
ConvenienceLow (space required, must switch between PCs)High (multitasking possible on a single device)
Primary UseDefense, critical national facilities, core networksGeneral enterprises, general financial-sector operations

Data Transfer Systems for Safe Data Exchange (Network Integration)

Concept: A bridge role within an air-gapped environment that minimizes the points of contact between networks while allowing only approved data to pass through.

Key Technologies:

  • Storage-Based: Delivers data and performs security scanning through an intermediate shared storage device (NAS/SAN).
  • Socket-Based: Transfers data between memory using a dedicated communication protocol.
  • IEEE 1394 / USB: Direct connection between networks via serial bus (mainly used recently in virtualized approaches).

III. Advanced Topics & Comparison

Even in a network-separated environment, bypass paths can emerge or configuration errors can cause the two networks to mix — a “network commingling” issue that becomes security’s Achilles heel.

Issue TypeCauseCountermeasure and Security Reinforcement
Unauthorized BypassTethering, use of rogue wireless APsIntroduce media control ( DLP ) and unauthorized wireless device detection ( WIPS )
Data Transfer MisuseBypassing security approval, unapproved large-volume transfersDetailed logging ( Audit Trail ) and integration with personal-data detection solutions
Convenience-Driven ExceptionsAllowing remote access for maintenance, etc.Adopt Zero Trust ( ZTNA ), ensure per-session visibility

Last updated 18 Aug 2026, 00:00 UTC. history