---
name: framework-financial-services-controls-ac-4.21
title: AC-4 (21) -  Physical or Logical Separation of Information Flows
description: 'Separate information flows logically or physically using _[Assignment: organization-defined mechanisms and/or techniques]_ to accomplish _[Assignment: organization-defined required separations by types of information]_.'
last-updated: 2026-08-26
---

> ## Documentation Index
> The table of contents for this documentation set is at https://cloud.ibm.com/docs/framework-financial-services-controls?format=markdown
> The index for all IBM Cloud docs is at: https://cloud.ibm.com/docs/llms.txt
> Use these files to discover more information as needed.

# AC-4 (21) -  Physical or Logical Separation of Information Flows
{: #ac-4.21}

## Control requirements
{: #control-requirements}



### AC-4 (21) - 0
{: #ac-4-21-0}


Separate information flows logically or physically using _[Assignment: organization-defined mechanisms and/or techniques]_ to accomplish _[Assignment: organization-defined required separations by types of information]_.












## NIST supplemental guidance
{: #nist-supplemental-guidance}

Enforcing the separation of information flows associated with defined types of data can enhance protection by ensuring that information is not commingled while in transit and by enabling flow control by transmission paths that are not otherwise achievable. Types of separable information include inbound and outbound communications traffic, service requests and responses, and information of differing security impact or classification levels.