Internet DRAFT - draft-daniel-6lowpan-interoperability
draft-daniel-6lowpan-interoperability
Network Working Group K. Kim, Ed.
Internet-Draft S. Yoo
Expires: January 10, 2006 H. Kim
Ajou University
S. Daniel Park, Ed.
SAMSUNG Electronics
J. Lee
NCA
July 9, 2005
Interoperability of 6LoWPAN
draft-daniel-6lowpan-interoperability-01.txt
Status of this Memo
By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on January 10, 2006.
Copyright Notice
Copyright (C) The Internet Society (2005).
Abstract
This document specifies the gateway architecture for the
Kim, et al. Expires January 10, 2006 [Page 1]
Internet-Draft Interoperability of 6LoWPAN July 2005
interoperability between 6LoWPAN and external IPv6 networks. The
gateway does the compression and decompression of IPv6 packets and
performs the mapping between 16 bit short addresses and the IPv6
addresses for both the external IPv6 networks and 6LowPAN,
respectively.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1 Requirements notation . . . . . . . . . . . . . . . . . . 4
3. Gateway Architecture for Interoperability . . . . . . . . . . 4
3.1 Mapping Tables . . . . . . . . . . . . . . . . . . . . . . 5
3.1.1 Internal Device Address Mapping Table . . . . . . . . 6
3.1.2 External Device Address Mapping Table . . . . . . . . 6
3.2 Registration . . . . . . . . . . . . . . . . . . . . . . . 7
3.3 Multiple Gateways . . . . . . . . . . . . . . . . . . . . 7
4. Header Compression . . . . . . . . . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
6. Security Considerations . . . . . . . . . . . . . . . . . . . 7
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 8
Intellectual Property and Copyright Statements . . . . . . . . 10
Kim, et al. Expires January 16, 2006 [Page 2]
Internet-Draft Interoperability of 6LoWPAN July 2005
1. Introduction
6LoWPAN is an IPv6 based low-power wireless personal area network
which is comprised of devices that conform to the IEEE 802.15.4-2003
standard[ieee802.15.4]. As described in [I-D.kushalnagar-lowpan-
goals-assumptions], there are several issues to be solved for
enabling IP communication between 6LoWPAN devices. The limited
packet size of 6LoWPANs is one of them; The PDU size of IEEE 802.15.4
is 127 octets while the MTU size of IPv6 packets is 1280 octets.
[I-D.montenegro-lowpan-ipv6-over-802.15.4] introduces the adaption
layer of fragmentation and reassembly for IPv6 packets, while
providing a header compression scheme for reducing the size of the
IPv6 header.
The issue proposed in this document is about the interoperability
between the external IPv6 networks and 6LoWPAN. As shown in
[I-D.kushalnagar-lowpan-goals-assumptions], it is obvious that the
interoperability is one of the very basic requirements of providing
IP connectivity to 6LoWPAN. This document specifies the gateway
architecture for the interoperability. The gateway does the
compression and decompression of IPv6 packets and performs the
mapping between 16 bit short addresses and the IPv6 addresses for
both the external IPv6 networks and 6LowPAN, respectively.
[I-D.montenegro-lowpan-ipv6-over-802.15.4] didn't define transmission
between external IPv6 networks and 6LoWPAN. For external IPv6
packets, it cannot compress the address of the packets. So, the
mapping between 16-bit short addresses and the IPv6 addresses is
necessary in order to communicate with external IPv6 networks.
Notice that the mapping is not about 64-bit extend addresses but 16-
bit short addresses. The reason is why using 16-bit short addresses
is more efficient for the transmission than 64-bit extend addresses.
So, this document describes the mapping 16-bit short addresses from
the addresses for 6LoWPAN as well as the mapping for external IPv6
networks.
This document is based on [I-D.montenegro-lowpan-ipv6-over-802.15.4]
for the adaptation layer of fragmentation and reassembly, the
stateless address auto-configuration based on EUI-64[EUI64], the IPv6
link local address, the unicast address mapping, and the encoding of
UDP header fields.
2. Terminology
Kim, et al. Expires January 16, 2006 [Page 3]
Internet-Draft Interoperability of 6LoWPAN July 2005
ET:
Expiration Time
IID:
Interface IDentifier
MAC:
Media Access Control
MTU:
Maximum Transmission Unit
PAN:
Personal Area Network
PDU:
Protocol Data Unit
2.1 Requirements notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
3. Gateway Architecture for Interoperability
This section defines the gateway architecture for the
interoperability between IPv6 networks and 6LoWPAN. The gateway
SHOULD do the fragmentation and reassembly at the sub-IP layer for
external IPv6 packets to/from 6LoWPAN. The main function of the
fragmentation and reassembly is the same as in [I-D.montenegro-
lowpan-ipv6-over-802.15.4] except that the traffic is come from/to
the external IPv6 networks.
The gateway SHOULD do the compression and decompression of IPv6
packets in between IPv6 networks and 6LoWPAN. The compression
implies the dettaching the 64-bit address prefix from the destination
address of an IPv6 packet coming from external IPv6 networks in order
to obtain the EUI-64 identifier for the IEEE 802.15.4 destination.
The decompression is the exact opposite operation to the compression.
The gateway MAY further compress IPv6 packets by introducing or
mapping (16-bit) short addresses for both the external IPv6 networks
and 6LoWPAN. The gateway MAY maintain mapping table(s) for this
translation. The mapping SHOULD be applied to both the IPv6
addresses of external IPv6 networks and 6LoWPAN, while the mapping
table entries for them are different from each other. Notice that
for 6LoWPAN devices, the mapping of a 16-bit short address is done
for the EUI-64 identifier which is obtained by the above mentioned
compression, not the 128-bit IPv6 address. In this document, we
defines two mapping table types for external IPv6 networks and
6LoWPAN which will be described in Section 3.1.
Kim, et al. Expires January 16, 2006 [Page 4]
Internet-Draft Interoperability of 6LoWPAN July 2005
For communicating with external IPv6 networks, there are two possible
traffic: inbound traffic from an external IPv6 network to an internal
6LoWPAN and outbound traffic from an internal 6LoWPAN to an external
IPv6 network.
Inbound traffic
For the destination address of an inbound IPv6 packet, the gateway
maps the IID of the destination to the corresponding (16-bit)
short address using the internal device address mapping table. In
a compressed packet, the short address is put into the 'Address of
final destination' field of the final destination field and the
'S' field is set 1 in sub-IP. The assignment of the 16-bit short
address for an IID depends on the assignment strategy which is out
of scope of this document. For the source address, the gateway
assigns and maps an external 16-bit short address in the external
device address mapping table. The assignment strategy for an
external short address is TBD. The external short address will be
deleted after the expiration time which will be described in
Section 3.1.2.
Note: [I-D.montenegro-lowpan-ipv6-over-802.15.4] did not describe
about the source address of the originator though do about the
final destination field. The context for the source address is
valid if and only if it defines the source address of the
originator in sub-IP.
Outbound traffic
The outbound traffic can be classified by the following two
categories. First category is the reply traffic for the above
mentioned inbound traffic. In this case, a 6LoWPAN device can use
16-bit short addresses for both destination and source addresses.
Notice that there is an assigned external short address in the
external device address mapping table prior to the reply traffic
and the definition for the source addressof the originator in
sub-IP. The outbound traffic should arrive at the gateway before
the expiration time of the external short address. The operation
for the outbound traffic after the expiration is TBD. Second
category is the originating outbound traffic. Because there is no
mapped external short address for the destination of external IPv6
networks, there can be no compression for the destination in this
case.
3.1 Mapping Tables
The gateway MAY have the internal and external device address mapping
tables.
Kim, et al. Expires January 16, 2006 [Page 5]
Internet-Draft Interoperability of 6LoWPAN July 2005
3.1.1 Internal Device Address Mapping Table
This table consists of 64-bit interface identifier (IID) and 16-bit
short address. This table MUST contain the mapping information of
all the devices in 6LoWPAN. The maximum size of the mapping table is
2^16 entries. The case of multiple gateways (i.e. multiple mapping
tables) is dealt in Section 3.3.
64 bits 16 bits
+--------------------------------------+
| IID | Short Addr.|
+--------------------------------------+
<Fig. 1. Internal Device Address Mapping Table>
Interface Identifier: The 64 bit IID assigned to each 6LoWPAN
device.
Short Address: The 16 bit short address assigned to each 6LoWPAN
device.
3.1.2 External Device Address Mapping Table
This table consists of 128-bit IPv6 address, 16-bit short address and
ET(Expiration Time).
128 bits 16 bits 8 bits
+-------------------------------------+------------+-------+
| IPv6 Addr. | Short Addr.| ET |
+-------------------------------------+------------+-------+
<Fig. 2. External Device Address Mapping Table>
IPv6 Address: The IPv6 address of the external device.
Short Address: The 16 bit short address for the external IPv6
address.
Kim, et al. Expires January 16, 2006 [Page 6]
Internet-Draft Interoperability of 6LoWPAN July 2005
ET: The expiration time field.
3.2 Registration
The gateway maintains the internal device mapping table for the
mapping of 16 bit short address for all devices in the 6LoWPAN. In
order to setup the table, there should be a registration procedure
which is TBD.
3.3 Multiple Gateways
In this document, we assume that there is one gateway for a 6LoWPAN,
even though the number of gateways is not restricted. The more
communication with external IPv6 networks, the more overheads the
gateway undergo. One of the methods reducing the overheads is
distributing the burden over multiple gateways. We will cover such
issues as distributed mapping of 16-bit short addresses by multiple
gateways and (on-demand or hierarchical) routing and tunneling
between gateways, in future revision.
4. Header Compression
The method of the header compression follows [I-D.montenegro-
lowpan-ipv6-over-802.15.4]. The size of the address in the 'M' field
is reduced because the gateway maps 64-bit link-layer addresses to
16-bit short addresses.
5. IANA Considerations
There is at the time of this publication no IANA consideration.
6. Security Considerations
TBD
7. Acknowledgements
Thanks to Prof. Byeong-Hee Roh, Jea Tek Ryu, and Minho Lee for their
useful discussions and supports for writing this document.
8. References
[EUI64] IEEE
http://standards.ieee.org/regauth/oui/tutorials/
EUI64.html, "GUIDELINES FOR 64-BIT GLOBAL IDENTIFIER
(EUI-64) REGISTRATION AUTHORITY".
Kim, et al. Expires January 16, 2006 [Page 7]
Internet-Draft Interoperability of 6LoWPAN July 2005
[I-D.kushalnagar-lowpan-goals-assumptions]
Kushalnagar, N. and G. Montenegro, "6LoWPAN: Overview,
Assumptions, Problem Statement and Goals",
draft-kushalnagar-lowpan-goals-assumptions-00 (work in
progress), February 2005.
[I-D.montenegro-lowpan-ipv6-over-802.15.4]
Montenegro, G., "Transmission of IPv6 Packets over IEEE
802.15.4 Networks",
draft-montenegro-lowpan-ipv6-over-802.15.4-02 (work in
progress), February 2005.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, December 1998.
[ieee802.15.4]
IEEE Compure Society, "IEEE Std. 802.15.4-2003", IEEE Std.
802.15.4-2003, October 2003.
Authors' Addresses
Ki-Hyung Kim
Ajou University
San 5 Wonchun-dong, Yeongtong-gu
Suwon-si, Gyeonggi-do 442-749
KOREA
Phone: +82 31 219 2433
Email: kkim86@ajou.ac.kr
Seung Wha Yoo
Ajou University
San 5 Wonchun-dong, Yeongtong-gu
Suwon-si, Gyeonggi-do 442-749
KOREA
Phone: +82 31 219 1603
Email: swyoo@ajou.ac.kr
Kim, et al. Expires January 16, 2006 [Page 8]
Internet-Draft Interoperability of 6LoWPAN July 2005
Hee Jung Kim
Ajou University
San 5 Wonchun-dong, Yeongtong-gu
Suwon-si, Gyeonggi-do 442-749
KOREA
Phone: +82 31 219 1895
Email: rla81@ajou.ac.kr
Soohong Daniel Park
Mobile Platform Laboratory, SAMSUNG Electronics
416 Maetan-3dong, Yeongtong-gu
Suwon-si, Gyeonggi-do 442-742
KOREA
Phone: +82 31 200 4508
Email: soohong.park@samsung.com
Jae Ho Lee
National Computerization Agency
NCA Bldg, 77, Mugyo-dong, Chung-ku
Seoul, 100-775
KOREA
Phone: +82 2 2131 0250
Email: ljh@nca.or.kr
Kim, et al. Expires January 16, 2006 [Page 9]
Internet-Draft Interoperability of 6LoWPAN July 2005
Intellectual Property Statement
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at
ietf-ipr@ietf.org.
Disclaimer of Validity
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Copyright Statement
Copyright (C) The Internet Society (2005). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights.
Acknowledgment
Funding for the RFC Editor function is currently provided by the
Internet Society.
Kim, et al. Expires January 16, 2006 [Page 10]
