diff --git a/common/protocol/encoding.go b/common/protocol/encoding.go
new file mode 100644
index 000000000..85a423cc7
--- /dev/null
+++ b/common/protocol/encoding.go
@@ -0,0 +1,27 @@
+package protocol
+
+import (
+	"io"
+
+	"github.com/v2ray/v2ray-core/common/alloc"
+)
+
+type RequestEncoder interface {
+	EncodeHeader(*RequestHeader) *alloc.Buffer
+	EncodeBody(io.Writer) io.Writer
+}
+
+type RequestDecoder interface {
+	DecodeHeader(io.Reader) *RequestHeader
+	DecodeBody(io.Reader) io.Reader
+}
+
+type ResponseEncoder interface {
+	EncodeHeader(*ResponseHeader) *alloc.Buffer
+	EncodeBody(io.Writer) io.Writer
+}
+
+type ResponseDecoder interface {
+	DecodeHeader(io.Reader) *ResponseHeader
+	DecodeBody(io.Reader) io.Reader
+}
diff --git a/common/protocol/headers.go b/common/protocol/headers.go
new file mode 100644
index 000000000..887fbae46
--- /dev/null
+++ b/common/protocol/headers.go
@@ -0,0 +1,33 @@
+package protocol
+
+import (
+	v2net "github.com/v2ray/v2ray-core/common/net"
+)
+
+type RequestCommand byte
+
+const (
+	RequestCommandTCP = RequestCommand(0x01)
+	RequestCommandUDP = RequestCommand(0x02)
+)
+
+type RequestOption byte
+
+const (
+	RequestOptionChunkStream = RequestOption(0x01)
+)
+
+type RequestHeader struct {
+	Version byte
+	User    *User
+	Command RequestCommand
+	Option  RequestOption
+	Address v2net.Address
+	Port    v2net.Port
+}
+
+type ResponseCommand interface{}
+
+type ResponseHeader struct {
+	Command ResponseCommand
+}