diff --git a/agents/fsagent.go b/agents/fsagent.go
index 97456dab4..8c4234a9d 100644
--- a/agents/fsagent.go
+++ b/agents/fsagent.go
@@ -89,40 +89,45 @@ func (fsa *FSsessions) createHandlers() map[string][]func(string, int) {
 
 // Sets the call timeout valid of starting of the call
 func (fsa *FSsessions) setMaxCallDuration(uuid string, connIdx int,
-	maxDur time.Duration, destNr string) error {
+	maxDur time.Duration, destNr string) (err error) {
+	// set variable_cgr_max_usage to the fs channel
+	if _, err = fsa.conns[connIdx].SendApiCmd(
+		fmt.Sprintf("uuid_setvar %s %s %d \n\n",
+			uuid, VarCGRMaxUsage, int(maxDur.Seconds()))); err != nil {
+		utils.Logger.Err(
+			fmt.Sprintf("<%s> Could not set %s variable to freeswitch channel, error: <%s>, connIdx: %v",
+				utils.FreeSWITCHAgent, VarCGRMaxUsage, err.Error(), connIdx))
+		return
+	}
 	if len(fsa.cfg.EmptyBalanceContext) != 0 {
-		_, err := fsa.conns[connIdx].SendApiCmd(
+		_, err = fsa.conns[connIdx].SendApiCmd(
 			fmt.Sprintf("uuid_setvar %s execute_on_answer sched_transfer +%d %s XML %s\n\n",
 				uuid, int(maxDur.Seconds()), destNr, fsa.cfg.EmptyBalanceContext))
 		if err != nil {
 			utils.Logger.Err(
 				fmt.Sprintf("<%s> Could not transfer the call to empty balance context, error: <%s>, connIdx: %v",
 					utils.FreeSWITCHAgent, err.Error(), connIdx))
-			return err
 		}
-		return nil
+		return
 	}
 	if len(fsa.cfg.EmptyBalanceAnnFile) != 0 {
-		if _, err := fsa.conns[connIdx].SendApiCmd(
+		if _, err = fsa.conns[connIdx].SendApiCmd(
 			fmt.Sprintf("sched_broadcast +%d %s playback!manager_request::%s aleg\n\n",
 				int(maxDur.Seconds()), uuid, fsa.cfg.EmptyBalanceAnnFile)); err != nil {
 			utils.Logger.Err(
 				fmt.Sprintf("<%s> Could not send uuid_broadcast to freeswitch, error: <%s>, connIdx: %v",
 					utils.FreeSWITCHAgent, err.Error(), connIdx))
-			return err
 		}
-		return nil
+		return
 	}
-	_, err := fsa.conns[connIdx].SendApiCmd(
+	if _, err = fsa.conns[connIdx].SendApiCmd(
 		fmt.Sprintf("uuid_setvar %s execute_on_answer sched_hangup +%d alloted_timeout\n\n",
-			uuid, int(maxDur.Seconds())))
-	if err != nil {
+			uuid, int(maxDur.Seconds()))); err != nil {
 		utils.Logger.Err(
 			fmt.Sprintf("<%s> Could not send sched_hangup command to freeswitch, error: <%s>, connIdx: %v",
 				utils.FreeSWITCHAgent, err.Error(), connIdx))
-		return err
 	}
-	return nil
+	return
 }
 
 // Sends the transfer command to unpark the call to freeswitch
diff --git a/agents/fsevent.go b/agents/fsevent.go
index c6b6cdbd3..36b91028a 100644
--- a/agents/fsevent.go
+++ b/agents/fsevent.go
@@ -75,6 +75,7 @@ const (
 	VarAnswerEpoch           = "variable_answer_epoch"
 	VarCGRACD                = varPrefix + utils.CgrAcd
 	VarCGROriginHost         = varPrefix + utils.CGROriginHost
+	VarCGRMaxUsage           = "cgr_max_usage"
 )
 
 func NewFSEvent(strEv string) (fsev FSEvent) {
diff --git a/sessions/sessions.go b/sessions/sessions.go
index a59f93b53..43ecaf769 100644
--- a/sessions/sessions.go
+++ b/sessions/sessions.go
@@ -2123,7 +2123,7 @@ func (sS *SessionS) BiRPCv1AuthorizeEvent(ctx *context.Context,
 
 	if !args.GetAttributes && !args.AuthorizeResources &&
 		!args.GetMaxUsage && !args.GetRoutes {
-		return utils.NewErrMandatoryIeMissing("subsystems")
+		return utils.NewErrMandatoryIeMissing(utils.Subsystems)
 	}
 	if args.GetAttributes {
 		rplyAttr, err := sS.processAttributes(args.CGREvent, args.AttributeIDs, false)
@@ -2409,7 +2409,7 @@ func (sS *SessionS) BiRPCv1InitiateSession(ctx *context.Context,
 	// end of RPC caching
 
 	if !args.GetAttributes && !args.AllocateResources && !args.InitSession {
-		return utils.NewErrMandatoryIeMissing("subsystems")
+		return utils.NewErrMandatoryIeMissing(utils.Subsystems)
 	}
 	originID, _ := args.CGREvent.FieldAsString(utils.OriginID)
 	if args.GetAttributes {
@@ -2650,7 +2650,7 @@ func (sS *SessionS) BiRPCv1UpdateSession(ctx *context.Context,
 	// end of RPC caching
 
 	if !args.GetAttributes && !args.UpdateSession {
-		return utils.NewErrMandatoryIeMissing("subsystems")
+		return utils.NewErrMandatoryIeMissing(utils.Subsystems)
 	}
 
 	if args.GetAttributes {
@@ -2795,7 +2795,7 @@ func (sS *SessionS) BiRPCv1TerminateSession(ctx *context.Context,
 	}
 	// end of RPC caching
 	if !args.TerminateSession && !args.ReleaseResources {
-		return utils.NewErrMandatoryIeMissing("subsystems")
+		return utils.NewErrMandatoryIeMissing(utils.Subsystems)
 	}
 
 	ev := engine.MapEvent(args.CGREvent.Event)
diff --git a/sessions/sessionscover_test.go b/sessions/sessionscover_test.go
index d7ca17171..bb72b5b57 100644
--- a/sessions/sessionscover_test.go
+++ b/sessions/sessionscover_test.go
@@ -2453,7 +2453,7 @@ func TestBiRPCv1AuthorizeEvent(t *testing.T) {
 	args.CGREvent = cgrEvent
 	//RPC caching
 	sessions.cgrCfg.CacheCfg().Partitions[utils.CacheRPCResponses].Limit = -1
-	expected = "MANDATORY_IE_MISSING: [subsystems]"
+	expected = "MANDATORY_IE_MISSING: [Subsystems]"
 
 	caches := engine.NewCacheS(cfg, dm, nil)
 	value := &utils.CachedRPCResponse{
@@ -2900,7 +2900,7 @@ func TestBiRPCv1InitiateSession1(t *testing.T) {
 	args = NewV1InitSessionArgs(false, []string{},
 		false, []string{}, false, []string{}, false, false,
 		cgrEvent, true)
-	expected = "MANDATORY_IE_MISSING: [subsystems]"
+	expected = "MANDATORY_IE_MISSING: [Subsystems]"
 	if err := sessions.BiRPCv1InitiateSession(context.Background(), args, rply); err == nil || err.Error() != expected {
 		t.Errorf("Expected %+v, received %+v", expected, err)
 	}
@@ -3211,7 +3211,7 @@ func TestBiRPCv1UpdateSession1(t *testing.T) {
 
 	args = NewV1UpdateSessionArgs(false, []string{}, false,
 		cgrEvent, true)
-	expected = "MANDATORY_IE_MISSING: [subsystems]"
+	expected = "MANDATORY_IE_MISSING: [Subsystems]"
 	if err := sessions.BiRPCv1UpdateSession(context.Background(), args, rply); err == nil || err.Error() != expected {
 		t.Errorf("Exepected %+v, received %+v", expected, err)
 	}
@@ -3346,7 +3346,7 @@ func TestBiRPCv1TerminateSession1(t *testing.T) {
 
 	cgrEvent.ID = utils.EmptyString
 	args = NewV1TerminateSessionArgs(false, false, false, nil, false, nil, cgrEvent, true)
-	expected = "MANDATORY_IE_MISSING: [subsystems]"
+	expected = "MANDATORY_IE_MISSING: [Subsystems]"
 	if err := sessions.BiRPCv1TerminateSession(context.Background(), args, &reply); err == nil || err.Error() != expected {
 		t.Errorf("Exepected %+v, received %+v", expected, err)
 	}