One document matched: draft-jeong-adhoc-ip-addr-autoconf-01.txt
Differences from draft-jeong-adhoc-ip-addr-autoconf-00.txt
Individual Submission
Internet Draft Jaehoon Paul Jeong
Jungsoo Park
Hyoungjun Kim
ETRI
Dongkyun Kim
KNU
<draft-jeong-adhoc-ip-addr-autoconf-01.txt>
Expires: April 2004 20 October 2003
Ad Hoc IP Address Autoconfiguration
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026 except that the right to
produce derivative works is not granted [1].
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.
Abstract
This document specifies the steps a node in ad hoc network takes in
deciding how to autoconfigure its IPv4 or IPv6 address in network
interface. Because the ad hoc IP address autoconfiguration in this
document considers ad hoc network's partition and mergence, the
address duplication that can be caused by ad hoc network's mergence
can be resolved.
Conventions used in this document
Jeong, et al. Expires - April 2004 [Page 1]
Internet-Draft Ad Hoc IP Address Autoconfiguration October 2003
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 RFC 2119 [2].
Table of Contents
1. Terminology...................................................2
2. Introduction..................................................3
3. Overview......................................................3
4. Message Format for Ad Hoc IP Address Autoconfiguration........4
4.1 Message Format for Ad Hoc IPv4 Address Autoconfiguration..4
4.2 Message Format for Ad Hoc IPv6 Address Autoconfiguration..5
5. Ad Hoc IP Address Autoconfiguration...........................7
5.1 Ad Hoc IPv4 Address Autoconfiguration.....................7
5.1.1 Network Prefix for IPv4 Ad Hoc Network..............7
5.1.2 Procedure of Ad Hoc IPv4 DAD........................7
5.2 Ad Hoc IPv6 Address Autoconfiguration.....................9
5.2.1 Network Prefix for IPv6 Ad Hoc Network..............9
5.2.2 Procedure of Ad Hoc IPv6 DAD.......................10
6. Maintenance of Upper-layer Session under Address Duplication.10
7. Security Considerations......................................11
8. Copyright....................................................11
9. Normative References.........................................12
10. Informative References......................................12
11. Acknowledgements............................................12
12. Authors' Addresses..........................................12
1. Terminology
This document uses the terminology described in [3][4]. In addition,
seven new terms are defined below:
Mobile Ad Hoc Network (MANET)
The network where mobile nodes can communicate with one another
without preexisting communication infrastructure, such as base
station or access point.
Duplicate Address Detection (DAD)
The process by which a node, which lacks an IP address,
determines address, determines whether a candidate address it
has selected is available or not. A node already equipped with
an IP address takes part in DAD in order to protect its IP
address from being accidentally used by another node.
Strong DAD
Jeong, et al. Expires - April 2004 [Page 2]
Internet-Draft Ad Hoc IP Address Autoconfiguration October 2003
The timed-based DAD for the purpose of checking if there is
address duplication in a connected MANET partition within a
finite bounded time interval [5].
Weak DAD
The DAD for the purpose of detecting address duplication during
ad hoc routing. Key is used for the purpose of detecting
duplicate IP addresses, which is selected to be unique by mobile
node. When mobile node receives a routing control packet, it
compares the pairs of address and key contained in the packet
with those in the routing table or cache [5].
Address Request (AREQ)
The message used during Strong DAD for the purpose of checking
if there is another node having the requested address [6].
Address Reply (AREP)
The message used during Strong DAD for the purpose of indicating
the requested address has already been utilized [6].
Address Error (AERR)
The message used during Weak DAD for the purpose of indicating
that an address duplication happened or that the address of peer
node has been changed.
2. Introduction
IPv6 stateless address autoconfiguration [5] provides a way to
autoconfigure either fixed or mobile nodes with one or more IPv6
addresses and default routes. But this is not suitable for multi-hop
ad hoc networks that has dynamic network topology. Ad hoc networks
become partitioned and merged as intermediate nodes move. In this
environment, IPv6 stateless address autoconfiguration should be able
to process the address duplication not only within a connected ad hoc
partition, but also in the case that two partitions having duplicate
addresses respectively become merged. This document provides ad hoc
IP address autoconfiguration in IPv4 ad hoc network as well as in
IPv6 ad hoc network.
3. Overview
IPv4 or IPv6 unicast address of ad hoc node is autoconfigured by IP
address autoconfiguration for ad hoc networks. The configuration of
address is comprised of three steps; (a) selection of random address,
Jeong, et al. Expires - April 2004 [Page 3]
Internet-Draft Ad Hoc IP Address Autoconfiguration October 2003
(b) verification of the uniqueness of the address and (c) assignment
of the address into network interface.
The duplication address detection (DAD) proposed in this document not
only checks address duplication during the initialization of address
configuration, but also checks and resolves address duplication
detected by intermediate nodes during ad hoc routing. Also, during
the resolution of address conflict, the sessions using the conflicted
address can be maintained until the sessions are closed.
The DAD for ad hoc network in this document is a hybrid scheme
consisting of two phases; (a) Strong DAD phase and (b) Weak DAD phase.
Within a connected ad hoc partition, Strong DAD can check quickly if
there is any address duplication or not. During ad hoc routing, Weak
DAD can find out if address duplication has occurred or not, when two
or more MANET partitions having duplicate addresses are merged.
4. Message Format for Ad Hoc IP Address Autoconfiguration
4.1 Message Format for Ad Hoc IPv4 Address Autoconfiguration
The mechanism of this document needs new ICMPv4 types for ad hoc IPv4
address autoconfiguration. Figure 1 shows the format of the messages
related to IPv4 address autoconfiguration.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Code | Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Identification |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Originator's IPv4 Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Requested or Duplicate IPv4 Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1. Message Format for Ad Hoc IPv4 Address Autoconfiguration
Fields:
Type 8-bit identifier of the type of ICMPv4 message.
Message Name Type
AREQ (TBD)
AREP (TBD)
AERR (TBD)
Jeong, et al. Expires - April 2004 [Page 4]
Internet-Draft Ad Hoc IP Address Autoconfiguration October 2003
Code 8-bit unsigned integer. As the code for message
type, the valid value is either 0 or 1. Code
value 1 in AERR message indicates that the peer
node's address has been changed. In the other
cases, code value is always 0.
Checksum 16-bit unsigned integer. The checksum for the
ICMPv4 message and parts of the IPv4 header
Identification 32-bit unsigned integer. The identification for
ad hoc address autoconfiguration message is used
to prevent duplicate AREQ message from being
flooded.
Originator's IPv4 Address
The IPv4 address of the sender of ad hoc address
autoconfiguration message.
Requested or Duplicate IPv4 Address
The requested IPv4 address in AREQ and AREP
messages, or the duplicate IPv4 address in AERR
message.
AREQ and AREP messages are used during Strong DAD and AERR message
during Weak DAD. Because AREQ message is forwarded by higher layer
than network layer through local broadcasting, "Identification" field
is necessary, in order not to flood the message sent previously again.
4.2 Message Format for Ad Hoc IPv6 Address Autoconfiguration
The mechanism of this document needs new ICMPv6 types for ad hoc IPv6
address autoconfiguration. Figure 2 shows the format of the messages
related to IPv6 address autoconfiguration.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Code | Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Identification |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Originator's IPv6 Address +
| |
Jeong, et al. Expires - April 2004 [Page 5]
Internet-Draft Ad Hoc IP Address Autoconfiguration October 2003
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Requested or Duplicate IPv6 Address +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2. Message Format for Ad Hoc IPv6 Address Autoconfiguration
Fields:
Type 8-bit identifier of the type of ICMPv6 message.
Message Name Type
AREQ (TBD)
AREP (TBD)
AERR (TBD)
Code 8-bit unsigned integer. As the code for message
type, the valid value is either 0 or 1. Code
value 1 in AERR message indicates that the peer
node's address has been changed. In the other
cases, code value is always 0.
Checksum 16-bit unsigned integer. The checksum for the
ICMPv6 message and parts of the IPv6 header
Identification 32-bit unsigned integer. The identification for
ad hoc address autoconfiguration message is used
to prevent duplicate AREQ message from being
flooded.
Originator's IPv6 Address
The IPv6 address of the sender of ad hoc address
autoconfiguration message.
Requested or Duplicate IPv6 Address
The requested IPv6 address in AREQ and AREP
messages, or the duplicate IPv6 address in AERR
message.
Jeong, et al. Expires - April 2004 [Page 6]
Internet-Draft Ad Hoc IP Address Autoconfiguration October 2003
5. Ad Hoc IP Address Autoconfiguration
The procedure of ad hoc IP address autoconfiguration in an ad hoc
node is comprised of two phases; (a) Strong DAD phase and (b) Weak
DAD phase. Especially, for Weak DAD, "Virtual IP Address" is used,
which is the combination of "IP Address" and "Key". During ad hoc
routing, with the value of Key, Weak DAD can detect IP address
duplication. Therefore, Weak DAD places a requirement for a new
field in the routing table -- namely, the inclusion of a "Key" field.
Also, most of routing control packets of ad hoc routing protocols
(e.g., link state packet) contain "Sequence Number" or
"Identification" field in order to allow a receiving node of the
control packets to determine whether it has recently seen copies of
the packets. This field is also used for the purpose of detecting
address duplication by Weak DAD.
Because this document does not consider the global connectivity to
the Internet, it assumes that MANET is temporary network isolated
from the Internet and the scope of addresses used in MANET is not
global, but local.
5.1 Ad Hoc IPv4 Address Autoconfiguration
5.1.1 Network Prefix for IPv4 Ad Hoc Network
For IPv4 address, "169.254/16" is used as IPv4 MANET exclusive prefix,
IPV4_MANET_PREFIX [6]. Among IPV4_MANET_PREFIX, IPv4 addresses in
the range 1 ~ 2047 (TMP_ADDR) in the low-order 16 bits are used for
temporary IPv4 unicast address during Strong DAD. The rest of
addresses in the range TMP_ADDR + 1 ~ 65534 in the low-order 16 bits
are used as tentative IPv4 address for actual IPv4 unicast address.
In the future, this prefix can be replaced with another one for ad
hoc network.
5.1.2 Procedure of Ad Hoc IPv4 DAD
During Strong DAD phase, an ad hoc node autoconfigures a unique IPv4
address in its network interface within a limited scope of a
connected MANET partition and during Weak DAD phase, the node
participates in DAD and ad hoc routing as follows;
Step (a) : A node selects a temporary address and configures it in
network interface.
Step (b) : The node selects a tentative address and makes an AREQ
message for the address. It initializes a variable for
retransmission of AREQ message, retrans_count, into 0.
Jeong, et al. Expires - April 2004 [Page 7]
Internet-Draft Ad Hoc IP Address Autoconfiguration October 2003
Step (c) : The node broadcasts the AREQ message in IPv4 MANET
broadcast address, 255.255.255.255, and increases the count for
transmission of AREQ message, retrans_count by 1. It waits for AREP
message until the timer for Strong DAD expires. If an AREP message
for the sent AREQ message arrives until the timer expires, the node
executes Step (e). Otherwise, it executes Step (d).
Step (d) : If retrans_count is equal to DAD_RETRIES (e.g., 3), the
node goes to Step (f). Otherwise, it goes to Step (c).
Step (e) : If the received AREP message is associated with the sent
AREQ message, the node returns to Step (b).
Step (f) : Because the requested address that is tentative is unique
in the connected partition, the node replaces the temporary address
with it as IPv4 unicast address of its network interface.
Step (g) : The node is ready to receive address autoconfiguration
message or ad hoc routing control packet. Ad hoc routing protocol is
either proactive or reactive. If the packet is address
autoconfiguration message, it executes Step (h). If the received
packet is ad hoc routing control packet, it executes Step (l).
Step (h) : If the received message is AREQ message, first of all, it
checks whether the received message is what was received previously
on the basis of "Source IP Address" field of IP datagram containing
the message and "Identification" field within the message or not. If
the packet is what was received previously, the node discards the
message, returning to Step (g). Otherwise, the node executes Step
(i). If the message is AREP, it executes Step (j). If the message
is AERR, it executes Step (k).
Step (i) : The node compares its address with the requested address
in the message. If two addresses are the same, it sends in unicast
the originator node an AREP message, indicating address duplication,
returning to Step (g). Otherwise, it floods or broadcasts the
message to neighbors, returning to Step (g).
Step (j) : If Destination IP address of the AREP message is the same
as its own IP address and the duplicate address in the AREP message
is corresponding to its own IP address under tentative state during
Strong DAD, the node starts Strong DAD procedure again, namely
returning to Step (a). If Destination IP address of the AREP message
is the same as its own but the duplicate address in the AREP message
isn't corresponding to its own under tentative state during Strong
DAD, it discards the message, returning to Step (g). Otherwise, it
only relays the message in unicast towards Destination IP address of
the AREP message, returning to Step (g). Notice that nodes under
Jeong, et al. Expires - April 2004 [Page 8]
Internet-Draft Ad Hoc IP Address Autoconfiguration October 2003
tentative state of Strong DAD for its address configuration SHOULD
NOT relay or forward other nodes' AREP messages.
Step (k) : If Destination IP address of the AERR message is the same
as its own IP address and the duplicate address in the AERR message
is the same as its own IP address, the node starts Strong DAD
procedure in order to autoconfigure a new address again, namely
returning to Step (a). If Destination IP address of the AERR message
is the same as its own but the duplicate address in the AERR message
isn't the same as its own, node discards the message, returning to
Step (g). Otherwise, it only relays the message in unicast towards
Destination IP address of the AERR message, returning to Step (g).
Notice that nodes under tentative state of Strong DAD for its address
configuration SHOULD NOT relay or forward other nodes' AERR messages.
Step (l) : The node investigates each IP address contained in control
packet to see whether for IP address, there is a matching entry in
routing table or cache. If there is a matching entry and the values
of two "Key"s are different, because an IP address conflict has
happened, the node sends in unicast an AERR message, indicating
address conflict, to one of the nodes using the duplicate address
that are associated with different "Key"s, returning to Step (g),
which it selects one of these two nodes by local policy (e.g., random
selection). Otherwise, it executes the rest of the procedure related
to processing ad hoc routing control packets, returning to Step (g).
Notice that there isn't any protection against accidental cases where
the two contenders for an IP address happen to select the same value
for "Key". That should be okay as long as (i) the key is long (in
bits), and (ii) the nodes are quite capable of producing truly random
numbers. Also, the intermediate routing points also have to maintain
the "Key" value for the two endpoints, at least during address
discovery. Even in the accidental cases where the two contenders for
an IP address happen to select the same value for "Key", address
duplication MAY be detected with "Sequence Number" or
"Identification" field of the control packet. Assume that a node
receives a routing control packet (e.g., link state packet). If the
values of "IP Address" and "Key" fields within the packet are the
same as its own and the value of "Sequence Number" field within the
packet is higher than the counter value for its own "Sequence Number",
except sequence number wrap-around, the node MAY decide that address
duplication has happened and resolve the duplication [7].
5.2 Ad Hoc IPv6 Address Autoconfiguration
5.2.1 Network Prefix for IPv6 Ad Hoc Network
For IPv6 address, "fec0:0:0:ffff::/64" is used as IPv6 MANET
exclusive prefix, IPV6_MANET_PREFIX [6]. Among the IPV6_MANET_PREFIX,
Jeong, et al. Expires - April 2004 [Page 9]
Internet-Draft Ad Hoc IP Address Autoconfiguration October 2003
"fec0:0:0:ffff::/96" is used as IPV6_MANET_INIT_PREFIX for temporary
unicast address during Strong DAD. The low-order 32 bits of the
temporary address are configured with 32-bit pseudo random number.
The rest of address range of IPV6_MANET_PREFIX except
IPV6_MANET_INIT_PREFIX is used for actual unicast address. The
address is tentative address until the uniqueness of it is verified
by Strong DAD.
Recently, IPv6 site-local address has been deprecated by IPv6 working
group. Since IETF-56 meeting, IPv6 working group has been discussing
local prefix for local networks separated from the Internet, such as
ad hoc network [8]. If ad hoc prefix is determined by IPv6 working
group, IPV6_MANET_PREFIX will have the new one for ad hoc network.
5.2.2 Procedure of Ad Hoc IPv6 DAD
An IPv6 ad hoc node autoconfigures a unique IPv6 address in its
network interface in the same way as an IPv4 ad hoc node like section
5.1.2.
6. Maintenance of Upper-layer Session under Address Duplication
When address duplication happens and the duplicate address is
replaced with another, the sessions above network layer can be broken.
So, for the survivability of upper-layer sessions using the duplicate
address, the notification of address change between the peer nodes is
necessary.
In order to allow data packets related to the sessions using the
duplicate address to be forwarded to destination nodes for a while,
after sending error message (i.e., AERR message) to the node related
to the duplicate address, the intermediate nodes that have perceived
address duplication SHOULD continue to forward on-the-fly data
packets associated with the sessions using the duplicate address, on
the basis of Virtual IP Address (i.e., combination of IP address and
key), until the route entry for the duplicate address expires. The
node that receives an AERR message SHOULD autoconfigure a new IPv6
address through Strong DAD and SHOULD simultaneously make the new
address that will be used by the old upper-layer sessions that used
the duplicate address as well as by new upper-layer sessions from
this time forward. The node SHOULD inform the peer nodes of the
change of address by sending AERR messages with code 1. The
"Originator's IP Address" field contains the duplicate address and
the "Requested IP Address" field contains a new address to be used
for the communication. After receiving the AERR message, the peer
node sends its packets to the node through IP tunneling. The
destination address in outer IP header is the new IP address of the
node that announced duplicate address and that in inner IP header is
Jeong, et al. Expires - April 2004 [Page 10]
Internet-Draft Ad Hoc IP Address Autoconfiguration October 2003
the duplicate IP address of the node. When the node receives
tunneled packet from the peer node, it decapsulates the packet and
delivers the data in the packet to upper layer. Both the node and
peer nodes maintain the information of duplicate address and use it
for processing IP tunneling.
7. Security Considerations
In order to provide secure ad hoc IP address autoconfiguration in ad
hoc network, we can use IPsec ESP with a null-transform to
authenticate ad hoc IP autoconfiguration messages or control packets,
which can be easily accomplished through the configuration of a group
pre-shared secret key for the trusted nodes.
8. Copyright
The following copyright notice is copied from RFC 2026 [Bradner,
1996], Section 10.4, and describes the applicable copyright for this
document.
Copyright (C) The Internet Society July 12, 2001. All Rights
Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph
are included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assignees.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS 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.
Jeong, et al. Expires - April 2004 [Page 11]
Internet-Draft Ad Hoc IP Address Autoconfiguration October 2003
9. Normative References
[1] Bradner, S., "The Internet Standards Process -- Revision 3", BCP
9, RFC 2026, October 1996.
[2] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[3] T. Narten, E. Nordmark and W. Simpson, "Neighbour Discovery for
IP version 6", RFC 2461.
[4] S. Thomson and T. Narten, "IPv6 Stateless Address
Autoconfiguration", RFC 2462.
[5] Nitin H. Vaidya, "Weak Duplicate Address Detection in Mobile Ad
Hoc Networks", MobiHoc 2002, June 2002.
[6] Charles E. Perkins, Jari T. Malinen, Ryuji Wakikawa, Elizabeth M.
Belding-Royer and Yuan Sun, "IP Address Autoconfiguration for Ad
Hoc Networks", draft-ietf-manet-autoconf-01.txt, November 2001.
10. Informative References
[7] Kilian Weniger, "Passive Duplicate Address Detection in Mobile Ad
Hoc Networks", IEEE WCNC 2003, March 2003.
[8] R. Hinden, "Unique Local IPv6 Unicast Addresses", draft-hinden-
ipv6-global-local-addr-02.txt, June 2003.
11. Acknowledgements
The authors would like to acknowledge the previous contributions of
the following people; Charles E. Perkins, Jari T. Malinen, Ryuji
Wakikawa, Elizabeth M. Belding-Royer and Yuan Sun. In addition, the
important definitions (e.g., Strong DAD and Weak DAD) and mechanisms
for finding and resolving duplicate address have been derived from
Nitin H. Vaidya's work. Especially, we thank for his contribution.
For the suggestion of Passive DAD, in aid of Weak DAD, we thank
Kilian Weniger.
12. Authors' Addresses
Jaehoon Paul Jeong
ETRI / PEC
161 Gajong-Dong, Yusong-Gu
Daejon 305-350
Korea
Jeong, et al. Expires - April 2004 [Page 12]
Internet-Draft Ad Hoc IP Address Autoconfiguration October 2003
Phone: +82 42 860 1664
Fax: +82 42 861 5404
EMail: paul@etri.re.kr
Jungsoo Park
ETRI / PEC
161 Gajong-Dong, Yusong-Gu
Daejon 305-350
Korea
Phone: +82 42 860 6514
Fax: +82 42 861 5404
EMail: pjs@etri.re.kr
Hyoungjun Kim
ETRI / PEC
161 Gajong-Dong, Yusong-Gu
Daejon 305-350
Korea
Phone: +82 42 860 6576
Fax: +82 42 861 5404
EMail: khj@etri.re.kr
Dongkyun Kim
Kyungpook National University
1370 Sankyuk-Dong, Puk-Gu
Daegu 702-701
Korea
Phone: +82 53 950 7571
Fax: +82 53 957 4846
EMail: dongkyun@knu.ac.kr
Jeong, et al. Expires - April 2004 [Page 13]
| PAFTECH AB 2003-2026 | 2026-04-23 04:14:21 |