diff --git a/src/transport/doIP.c b/src/transport/doIP.c
new file mode 100644
index 0000000..b977519
--- /dev/null
+++ b/src/transport/doIP.c
@@ -0,0 +1,117 @@
+
+/*
+ * Copyright (C) 2007-2010 Siemens AG
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*******************************************************************
+ *
+ * @author Sebastian.Kaebisch.EXT@siemens.com
+ * @version 0.3.1
+ * @contact Joerg.Heuer@siemens.com
+ *
+ ********************************************************************/
+
+/*
+ * This file implements the DoIP header writer and reader.
+ * Note: Not all functions are implemented yet.
+ *
+ */
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <math.h>
+#include <string.h>
+
+#include "doIP.h"
+
+int write_doIPNack(uint8_t* outStream, uint16_t* outStreamLength, uint8_t nackCode)
+{
+/*	if(outStreamLength<DOIP_HEADER_LENGTH+1)
+		return -1;*/
+
+	/* payload length=1 and nack payload type*/
+	*outStreamLength = 1;
+
+	write_doIPHeader(outStream,outStreamLength, DOIP_NEGATIVE_ACKNOWLEDGE);
+	outStream[8]=nackCode;
+
+	return 0;
+}
+
+int write_doIPHeader(uint8_t* outStream, uint16_t* outStreamLength, uint16_t payloadType)
+{
+
+	/* write DoIP version number 1=byte */
+	outStream[0]=DOIP_VERSION;
+
+	/* write inverse DoIP version */
+	outStream[1]=DOIP_VERSION_INV;
+
+
+	/* write payload type */
+	outStream[2] = (uint8_t)(payloadType & 0xFF);
+	outStream[3] = (uint8_t)(payloadType >> 8 & 0xFF);
+
+	/* write payload length */
+	outStream[4] = (uint8_t)(*outStreamLength & 0xFF);
+	outStream[5] = (uint8_t)(*outStreamLength>>8 & 0xFF);
+	outStream[6] = (uint8_t)(*outStreamLength>>16 & 0xFF);
+	outStream[7] = (uint8_t)(*outStreamLength>>24 & 0xFF);
+
+	/* here, the outStream length have to be resized by the DoIP offset*/
+	*outStreamLength += DOIP_HEADER_LENGTH;
+
+	return 0;
+}
+
+int read_doIPHeader(uint8_t* inStream, uint16_t inStreamLength, uint16_t* payloadLength)
+{
+	uint16_t payloadType=0;
+
+
+	/* check, if we support this DoIP version */
+	if(inStream[0]!=DOIP_VERSION && inStream[1]!=DOIP_VERSION_INV)
+		return DOIP_INCORRECT_PATTERN_FORMAT;
+
+
+	/* check, if we support this payload type*/
+	payloadType = inStream[3];
+	payloadType = (payloadType << 8 | inStream[2]);
+
+	if(payloadType != DOIP_EXI_TYPE && payloadType != DOIP_NEGATIVE_ACKNOWLEDGE)
+		return DOIP_UNKNOWN_PAYLOAD_TYPE;
+
+
+	/* determine payload length*/
+	*payloadLength = inStream[7];
+	*payloadLength = (*payloadLength << 8 | inStream[6]);
+	*payloadLength = (*payloadLength << 16 | inStream[5]);
+	*payloadLength = (*payloadLength << 24 | inStream[4]);
+
+	if((*payloadLength+DOIP_HEADER_LENGTH)!=inStreamLength)
+		return DOIP_INVALID_PAYLOAD_LENGTH;
+
+	/* if payload is a NACK read its NACK code and return it*/
+	/* TODO: should be handled by an extra method */
+	if(payloadType == DOIP_NEGATIVE_ACKNOWLEDGE)
+				return inStream[8];
+
+
+	return 0;
+}
+
diff --git a/src/transport/doIP.h b/src/transport/doIP.h
new file mode 100644
index 0000000..59fb980
--- /dev/null
+++ b/src/transport/doIP.h
@@ -0,0 +1,68 @@
+
+/*
+ * Copyright (C) 2007-2010 Siemens AG
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*******************************************************************
+ *
+ * @author Sebastian.Kaebisch.EXT@siemens.com
+ * @version 0.3.1
+ * @contact Joerg.Heuer@siemens.com
+ *
+ ********************************************************************/
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifndef DOIP_H_
+#define DOIP_H_
+
+/* generic DoIP header length */
+#define DOIP_HEADER_LENGTH 8
+
+/* define DoIP Version */
+#define DOIP_VERSION 0x01
+#define DOIP_VERSION_INV 0xFE
+
+/* define DoIP payload types*/
+#define DOIP_NEGATIVE_ACKNOWLEDGE 0x0000
+#define DOIP_EXI_TYPE 0xC350 /* == 50000 */
+
+
+/* Generic DoIP Header NACK codes */
+#define DOIP_INCORRECT_PATTERN_FORMAT 0x00
+#define DOIP_UNKNOWN_PAYLOAD_TYPE 0x01
+#define DOIP_MESSAGE_TOO_LARGE 0x02
+#define DOIP_OUT_OF_MEMORY 0x03
+#define DOIP_INVALID_PAYLOAD_LENGTH 0x04
+
+/* EXI NACK code */
+#define DOIP_INVALID_EXI_MESSAGE 0x05
+
+
+/* DoIP methods */
+int write_doIPNack(uint8_t* outStream, uint16_t* outStreamLength, uint8_t nackCode);
+
+int write_doIPHeader(uint8_t* outStream, uint16_t* outStreamLength, uint16_t payloadType);
+
+int read_doIPHeader(uint8_t* inStream, uint16_t inStreamLength, uint16_t* payloadLength);
+
+#endif /* DOIP_H_ */
+
+#ifdef __cplusplus
+}
+#endif