diff --git a/mux.go b/mux.go
index 7628ecc..8b8a947 100644
--- a/mux.go
+++ b/mux.go
@@ -3,11 +3,11 @@ package smux
 import "io"
 
 // Server is used to initialize a new server-side connection.
-func Server(conn io.ReadWriteCloser, maxframes, framesize int) (*Session, error) {
+func Server(conn io.ReadWriteCloser, maxframes int, framesize uint16) (*Session, error) {
 	return newSession(conn, false, maxframes, framesize), nil
 }
 
 // Client is used to initialize a new client-side connection.
-func Client(conn io.ReadWriteCloser, maxframes, framesize int) (*Session, error) {
+func Client(conn io.ReadWriteCloser, maxframes int, framesize uint16) (*Session, error) {
 	return newSession(conn, true, maxframes, framesize), nil
 }
diff --git a/session.go b/session.go
index ee159e5..0a1a83d 100644
--- a/session.go
+++ b/session.go
@@ -21,7 +21,7 @@ type Session struct {
 	// stream related
 	nextStreamID uint32
 	streams      map[uint32]*Stream
-	frameSize    int
+	frameSize    uint16
 
 	// rx pool control
 	tokens      chan struct{}
@@ -47,7 +47,7 @@ func (lw *lockedWriter) Write(p []byte) (n int, err error) {
 	return
 }
 
-func newSession(conn io.ReadWriteCloser, client bool, maxframes, framesize int) *Session {
+func newSession(conn io.ReadWriteCloser, client bool, maxframes int, framesize uint16) *Session {
 	s := new(Session)
 	s.conn = conn
 	s.frameSize = framesize
diff --git a/stream.go b/stream.go
index dc0f54e..3a59695 100644
--- a/stream.go
+++ b/stream.go
@@ -13,13 +13,13 @@ type Stream struct {
 	id             uint32
 	chNotifyReader chan struct{}
 	sess           *Session
-	frameSize      int
+	frameSize      uint16
 	die            chan struct{}
 	rlock          sync.Mutex
 	buffer         []byte
 }
 
-func newStream(id uint32, frameSize int, chNotifyReader chan struct{}, sess *Session) *Stream {
+func newStream(id uint32, frameSize uint16, chNotifyReader chan struct{}, sess *Session) *Stream {
 	s := new(Stream)
 	s.id = id
 	s.chNotifyReader = chNotifyReader
@@ -108,7 +108,7 @@ func (s *Stream) Close() error {
 
 func (s *Stream) split(bts []byte, cmd byte, sid uint32) []Frame {
 	var frames []Frame
-	for len(bts) > s.frameSize {
+	for len(bts) > int(s.frameSize) {
 		frame := newFrame(cmd, sid)
 		frame.data = make([]byte, s.frameSize)
 		n := copy(frame.data, bts)