diff --git a/common/net/port.go b/common/net/port.go
index 4da6baad..5882da05 100644
--- a/common/net/port.go
+++ b/common/net/port.go
@@ -39,11 +39,6 @@ func (p Port) Value() uint16 {
 	return uint16(p)
 }
 
-// Bytes returns the correspoding bytes of a Port, in big endian order.
-func (p Port) Bytes(b []byte) []byte {
-	return serial.Uint16ToBytes(p.Value(), b)
-}
-
 // String returns the string presentation of a Port.
 func (p Port) String() string {
 	return serial.Uint16ToString(p.Value())
diff --git a/common/protocol/address.go b/common/protocol/address.go
index e1cfb3ae..70028469 100644
--- a/common/protocol/address.go
+++ b/common/protocol/address.go
@@ -7,6 +7,7 @@ import (
 	"v2ray.com/core/common/buf"
 	"v2ray.com/core/common/net"
 	"v2ray.com/core/common/task"
+	"v2ray.com/core/common/vio"
 )
 
 type AddressOption func(*AddressParser)
@@ -166,7 +167,7 @@ func (p *AddressParser) ReadAddressPort(buffer *buf.Buffer, input io.Reader) (ne
 }
 
 func (p *AddressParser) writePort(writer io.Writer, port net.Port) error {
-	return common.Error2(writer.Write(port.Bytes(nil)))
+	return common.Error2(vio.WriteUint16(writer, port.Value()))
 }
 
 func (p *AddressParser) writeAddress(writer io.Writer, address net.Address) error {
diff --git a/proxy/vmess/encoding/commands.go b/proxy/vmess/encoding/commands.go
index 11d93d67..f3e7ef65 100644
--- a/proxy/vmess/encoding/commands.go
+++ b/proxy/vmess/encoding/commands.go
@@ -9,6 +9,7 @@ import (
 	"v2ray.com/core/common/protocol"
 	"v2ray.com/core/common/serial"
 	"v2ray.com/core/common/uuid"
+	"v2ray.com/core/common/vio"
 )
 
 var (
@@ -95,7 +96,7 @@ func (f *CommandSwitchAccountFactory) Marshal(command interface{}, writer io.Wri
 		common.Must2(writer.Write([]byte(hostStr)))
 	}
 
-	common.Must2(writer.Write(cmd.Port.Bytes(nil)))
+	common.Must2(vio.WriteUint16(writer, cmd.Port.Value()))
 
 	idBytes := cmd.ID.Bytes()
 	common.Must2(writer.Write(idBytes))