diff --git a/frontend/src/lib/utils.ts b/frontend/src/lib/utils.ts
index 32278fb..764d144 100644
--- a/frontend/src/lib/utils.ts
+++ b/frontend/src/lib/utils.ts
@@ -1,3 +1,52 @@
 export function toHex(v: number | undefined): string {
   return ("00" + v?.toString(16).toUpperCase()).substr(-2);
 }
+
+function parseDataRate(rate: string | undefined): number {
+    if (!rate) return 0;
+    
+    const match = rate.match(/^(\d+)\s*(Gbps|Mbps|Kbps|bps)$/i);
+    if (!match) return 0;
+    
+    const [, value, unit] = match;
+    const numValue = parseFloat(value);
+    
+    switch (unit.toLowerCase()) {
+        case 'gbps':
+            return numValue * 1000000;
+        case 'mbps':
+            return numValue * 1000;
+        case 'kbps':
+            return numValue;
+        case 'bps':
+            return numValue / 1000;
+        default:
+            return 0;
+    }
+}
+
+export function validateMBRGreaterThanGBR(QosFlows: any[]): { isValid: boolean; error?: string } {
+    for (let i = 0; i < QosFlows.length; i++) {
+        const qosFlow = QosFlows[i];
+        const gbrDL = parseDataRate(qosFlow.gbrDL);
+        const mbrDL = parseDataRate(qosFlow.mbrDL);
+        const gbrUL = parseDataRate(qosFlow.gbrUL);
+        const mbrUL = parseDataRate(qosFlow.mbrUL);
+
+        if (gbrDL && mbrDL && gbrDL >= mbrDL) {
+            return {
+                isValid: false,
+                error: `In S-NSSAI ${qosFlow.snssai}'s Flow Rule ${i+1}\nDownlink MBR must be greater than Downlink GBR`
+            };
+        }
+
+        if (gbrUL && mbrUL && gbrUL >= mbrUL) {
+            return {
+                isValid: false,
+                error: `In S-NSSAI ${qosFlow.snssai}'s Flow Rule ${i+1}\nUplink MBR must be greater than Uplink GBR`
+            };
+        }
+    }
+    
+    return { isValid: true };
+}
\ No newline at end of file
diff --git a/frontend/src/pages/ProfileCreate/index.tsx b/frontend/src/pages/ProfileCreate/index.tsx
index a34b215..aaedde2 100644
--- a/frontend/src/pages/ProfileCreate/index.tsx
+++ b/frontend/src/pages/ProfileCreate/index.tsx
@@ -11,6 +11,8 @@ import ProfileFormBasic from "./ProfileFormBasic";
 import ProfileFormUeAmbr from "./ProfileFormUeAmbr";
 import ProfileFormSessions from "./ProfileFormSessions";
 import { ProfileMapperImpl, FlowsMapperImpl } from "../../lib/dtos/profile";
+import { validateMBRGreaterThanGBR } from "../../lib/utils";
+
 function FormHOC(Component: React.ComponentType<any>) {
     return function (props: any) {
         return (
@@ -66,6 +68,12 @@ function ProfileCreate() {
     const profileMapper = new ProfileMapperImpl(new FlowsMapperImpl());
     const profile = profileMapper.mapFromDto(data);
 
+    const validation = validateMBRGreaterThanGBR(profile.QosFlows);
+    if (!validation.isValid) {
+      alert(validation.error);
+      return;
+    }
+
     axios
       .post("/api/profile", profile)
       .then(() => {
@@ -96,6 +104,12 @@ function ProfileCreate() {
     const profileMapper = new ProfileMapperImpl(new FlowsMapperImpl());
     const profile = profileMapper.mapFromDto(data);
 
+    const validation = validateMBRGreaterThanGBR(profile.QosFlows);
+    if (!validation.isValid) {
+      alert(validation.error);
+      return;
+    }
+
     axios
       .put("/api/profile/" + profile.profileName, profile)
       .then(() => {
diff --git a/frontend/src/pages/SubscriberCreate/index.tsx b/frontend/src/pages/SubscriberCreate/index.tsx
index 8f687e1..b483ede 100644
--- a/frontend/src/pages/SubscriberCreate/index.tsx
+++ b/frontend/src/pages/SubscriberCreate/index.tsx
@@ -12,6 +12,8 @@ import SubscriberFormUeAmbr from "./SubscriberFormUeAmbr";
 import SubscriberFormSessions from "./SubscriberFormSessions";
 import { FlowsMapperImpl as SubscriptionFlowsMapperImpl, SubscriptionMapperImpl } from "../../lib/dtos/subscription";
 import { FlowsMapperImpl as ProfileFlowsMapperImpl, ProfileMapperImpl } from "../../lib/dtos/profile";
+import { validateMBRGreaterThanGBR } from "../../lib/utils";
+
 function FormHOC(Component: React.ComponentType<any>) {
   return function (props: any) {
     return (
@@ -91,6 +93,12 @@ function SubscriberCreate() {
     const subscriberMapper = new SubscriptionMapperImpl(new SubscriptionFlowsMapperImpl());
     const subscription = subscriberMapper.mapFromDto(data);
 
+    const validation = validateMBRGreaterThanGBR(subscription.QosFlows);
+    if (!validation.isValid) {
+      alert(validation.error);
+      return;
+    }
+
     // Iterate subscriber data number.
     let supi = subscription.ueId;
     for (let i = 0; i < subscription.userNumber!; i++) {
@@ -127,6 +135,12 @@ function SubscriberCreate() {
     const subscriberMapper = new SubscriptionMapperImpl(new SubscriptionFlowsMapperImpl());
     const subscription = subscriberMapper.mapFromDto(data);
 
+    const validation = validateMBRGreaterThanGBR(subscription.QosFlows);
+    if (!validation.isValid) {
+      alert(validation.error);
+      return;
+    }
+
     axios
       .put("/api/subscriber/" + subscription.ueId + "/" + subscription.plmnID, subscription)
       .then(() => {