diff --git a/framemgr.go b/framemgr.go
index 0ed69d5..0783151 100644
--- a/framemgr.go
+++ b/framemgr.go
@@ -231,6 +231,9 @@ func (fm *FrameMgr) addToRecvWin(rf *Frame) bool {
 
 	if !fm.isIdInRange((int)(rf.Id), FRAME_MAX_ID) {
 		loggo.Debug("recv frame not in range %d %d", rf.Id, fm.recvid)
+		if !fm.isIdOld((int)(rf.Id), FRAME_MAX_ID) {
+			return true
+		}
 		return false
 	}
 
@@ -257,18 +260,6 @@ func (fm *FrameMgr) addToRecvWin(rf *Frame) bool {
 	return true
 }
 
-func (fm *FrameMgr) compareId(l int, r int) int {
-
-	if l < fm.recvid {
-		l += FRAME_MAX_ID
-	}
-	if r < fm.recvid {
-		r += FRAME_MAX_ID
-	}
-
-	return l - r
-}
-
 func (fm *FrameMgr) combineWindowToRecvBuffer() {
 
 	for {
@@ -401,3 +392,34 @@ func (fm *FrameMgr) isIdInRange(id int, maxid int) bool {
 	}
 	return false
 }
+
+func (fm *FrameMgr) compareId(l int, r int) int {
+
+	if l < fm.recvid {
+		l += FRAME_MAX_ID
+	}
+	if r < fm.recvid {
+		r += FRAME_MAX_ID
+	}
+
+	return l - r
+}
+
+func (fm *FrameMgr) isIdOld(id int, maxid int) bool {
+	if id > fm.recvid {
+		return false
+	}
+
+	end := fm.recvid + fm.windowsize*2
+	if end >= maxid {
+		if id >= end-maxid && id < fm.recvid {
+			return true
+		}
+	} else {
+		if id < fm.recvid {
+			return true
+		}
+	}
+
+	return false
+}
diff --git a/pingtunnel_test.go b/pingtunnel_test.go
index ded56f2..3a51a2b 100644
--- a/pingtunnel_test.go
+++ b/pingtunnel_test.go
@@ -79,4 +79,16 @@ func Test0001(t *testing.T) {
 	fm.recvid = 10
 	fm.windowsize = 10000
 	fmt.Println("fm.isIdInRange  = ", fm.isIdInRange(0, FRAME_MAX_ID))
+
+	fm.recvid = 7
+	fm.windowsize = 5
+	fmt.Println("fm.isIdOld  = ", fm.isIdOld(2, 10))
+
+	fm.recvid = 7
+	fm.windowsize = 5
+	fmt.Println("fm.isIdOld  = ", fm.isIdOld(1, 10))
+
+	fm.recvid = 3
+	fm.windowsize = 5
+	fmt.Println("fm.isIdOld  = ", fm.isIdOld(1, 10))
 }