diff --git a/features/fedramp_extensions.feature b/features/fedramp_extensions.feature
index 423497d98..92110a420 100644
--- a/features/fedramp_extensions.feature
+++ b/features/fedramp_extensions.feature
@@ -37,6 +37,7 @@ Examples:
   | component-has-authentication-method |
   | component-has-non-provider-responsible-role |
   | component-has-provider-responsible-role |
+  | component-has-used-by-link |
   | component-type |
   | control-implementation-status |
   | data-center-alternate |
@@ -183,6 +184,8 @@ Examples:
   | component-has-authentication-method-PASS.yaml |
   | component-has-non-provider-responsible-role-FAIL.yaml |
   | component-has-non-provider-responsible-role-PASS.yaml |
+  | component-has-used-by-link-FAIL.yaml |
+  | component-has-used-by-link-PASS.yaml |
   | component-responsible-role-references-party-FAIL.yaml |
   | component-responsible-role-references-party-PASS.yaml |
   | component-type-FAIL.yaml |
diff --git a/src/content/rev5/examples/ssp/xml/fedramp-ssp-example.oscal.xml b/src/content/rev5/examples/ssp/xml/fedramp-ssp-example.oscal.xml
index 91fd25b6e..2748dbc81 100644
--- a/src/content/rev5/examples/ssp/xml/fedramp-ssp-example.oscal.xml
+++ b/src/content/rev5/examples/ssp/xml/fedramp-ssp-example.oscal.xml
@@ -1196,6 +1196,7 @@
          </prop>
 
          <prop name="inherited-uuid" value="22222222-0000-4000-9001-009000000001" />
+         <link rel="used-by" href="#11111111-2222-4000-8000-009000000000"/>
 
          <status state="operational"/>
 
@@ -1425,6 +1426,7 @@
             </remarks>
          </prop>
          <link rel="provided-by" href="#11111111-2222-4000-8000-009000100003" />
+         <link rel="used-by" href="#11111111-2222-4000-8000-009000000000"/>
          <status state="operational"/>
 
          <responsible-role role-id="leveraged-authorization-users">
@@ -1525,6 +1527,7 @@
 
          <!-- <link href="11111111-2222-4000-8000-009000000000" rel="used-by"/> -->
          <link rel="api" href="https://api.example.com/v1" />
+         <link rel="used-by" href="#11111111-2222-4000-8000-009000000000"/>
          <status state="operational"/>
          <responsible-role role-id="provider">
             <party-uuid>11111111-2222-4000-8000-004000000018</party-uuid>
diff --git a/src/validations/constraints/content/ssp-component-has-used-by-link-INVALID.xml b/src/validations/constraints/content/ssp-component-has-used-by-link-INVALID.xml
new file mode 100644
index 000000000..8ba3c1d90
--- /dev/null
+++ b/src/validations/constraints/content/ssp-component-has-used-by-link-INVALID.xml
@@ -0,0 +1,11 @@
+<system-security-plan xmlns="http://csrc.nist.gov/ns/oscal/1.0" uuid="11111111-2222-4000-8000-000000000000">
+  <system-implementation>
+    <component uuid="11111111-2222-4000-8000-009000200001" type="service">
+      <!-- <link rel="used-by" href="#11111111-2222-4000-8000-009000000000"/> Missing at least one used-by link -->
+      <protocol name="ftp" uuid="11111111-2222-4000-8000-010000000001">
+        <title>Incoming FTP Service</title>
+        <port-range start="21" end="21" transport="TCP"/>
+      </protocol>
+    </component>
+  </system-implementation>
+</system-security-plan>
\ No newline at end of file
diff --git a/src/validations/constraints/fedramp-external-constraints.xml b/src/validations/constraints/fedramp-external-constraints.xml
index af7ae5b20..26382a527 100644
--- a/src/validations/constraints/fedramp-external-constraints.xml
+++ b/src/validations/constraints/fedramp-external-constraints.xml
@@ -555,6 +555,11 @@
                 <prop namespace="https://docs.oasis-open.org/sarif/sarif/v2.1.0" name="help-url" value="https://automate.fedramp.gov/documentation/ssp/4-ssp-template-to-oscal-mapping/#leveraged-fedramp-authorized-services"/>
                 <message>A FedRAMP SSP with service components and CLI software components performing cross-boundary network communication MUST indicate exactly one time if the point of implementation is internal or external to the system.</message>
             </expect>
+            <expect id="component-has-used-by-link" target="component[protocol]" test="count(link[@rel='used-by']) >= 1" level="ERROR">
+                <formal-name>Component Has Used-By Link</formal-name>
+                <prop namespace="https://docs.oasis-open.org/sarif/sarif/v2.1.0" name="help-url" value="https://automate.fedramp.gov/documentation/ssp/4-ssp-template-to-oscal-mapping/#ports-protocols-and-services"/>
+                <message>A FedRAMP SSP's component MUST identify which other components use it via network communication. Component "{ @uuid }" exposes ports for other components to connect, but does not identify which components use it.</message>
+            </expect>
             <is-unique id="unique-inventory-item-asset-id" target="inventory-item/prop[@name='asset-id']">
                 <formal-name>Unique Asset Identifier</formal-name>
                 <description>Ensure each inventory item has a unique asset-id property.</description>
diff --git a/src/validations/constraints/unit-tests/component-has-used-by-link-FAIL.yaml b/src/validations/constraints/unit-tests/component-has-used-by-link-FAIL.yaml
new file mode 100644
index 000000000..6d955c12e
--- /dev/null
+++ b/src/validations/constraints/unit-tests/component-has-used-by-link-FAIL.yaml
@@ -0,0 +1,9 @@
+test-case:
+  name: Negative Test for component-has-used-by-link
+  description: >-
+    This test case validates the behavior of constraint
+    component-has-used-by-link
+  content: ../content/ssp-component-has-used-by-link-INVALID.xml
+  expectations:
+    - constraint-id: component-has-used-by-link
+      result: fail
diff --git a/src/validations/constraints/unit-tests/component-has-used-by-link-PASS.yaml b/src/validations/constraints/unit-tests/component-has-used-by-link-PASS.yaml
new file mode 100644
index 000000000..78fbc167f
--- /dev/null
+++ b/src/validations/constraints/unit-tests/component-has-used-by-link-PASS.yaml
@@ -0,0 +1,9 @@
+test-case:
+  name: Positive Test for component-has-used-by-link
+  description: >-
+    This test case validates the behavior of constraint
+    component-has-used-by-link
+  content: ../../../content/rev5/examples/ssp/xml/fedramp-ssp-example.oscal.xml
+  expectations:
+    - constraint-id: component-has-used-by-link
+      result: pass