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Dynamic Tunnel Management Protocol
for IPv4 Traversal of IPv6 Mobile Network
Jaehoon Jeong
Protocol Engineering Center, ETRI
[email protected]
http://www.nemo.6ants.net/
VTC 2004 Fall
Contents
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Motivation
Network Mobility (NEMO)
Related Work
Main Idea
Mobile Router in NEMO
Service Scenarios in IPv6 NEMO
Auto-switching b/w WLAN & CDMA
IPv4 Datagram Layout for
IPv6-in-IPv4 Tunnel Management
Testbed for IPv6 NEMO
Conclusion
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Motivation
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Network Mobility (NEMO) Basic Support protocol
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Object of NEMO
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NEMO is being developed at IETF NEMO working group
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Limitation of Current NEMO Protocol
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NEMO allows a mobile network reachable in the Internet through Mobile
IPv6 Extension.
NEMO supports network mobility only in IPv6 Internet through bi-directional
tunneling between Mobile Router (MR) and Home Agent (HA).
Goal of This Paper
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Support of IPv4 Traversal of IPv6 Mobile Network in the
current Internet that consists nearly of IPv4 networks.
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Network Mobility (NEMO) – 1/2
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Role of NEMO Protocol
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Session Continuity of Mobile Network Node (MNN)
Connectivity of MNN
Reachability of MNN
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Location Management
Key Idea of NEMO
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HA forwards data packets destined for Mobile Network.
HA maintains the forwarding information related to Mobile
Network Prefix(es).
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Network Mobility (NEMO) – 2/2
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Management of Mobile Network Prefix
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Binding Update of Implicit Mode
Binding Update of Explicit Mode
Dynamic Routing Protocols
Refer to NEMO draft for detailed information
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draft-ietf-nemo-basic-support-03.txt
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Related Work
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Vertical Handover based on L2 Triggers
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Vertical Handover
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Handover between different kinds of physical networks
L2 Trigger
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An event that occurs at the Link Layer that is forwarded to the
upper layer, i.e., Layer 3.
Five L2 triggers were proposed:
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L2 Hint
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Information that can be optionally transported with an L2 trigger
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Link Up, Link Down, Source Trigger, Target Trigger or Mobile Trigger
LINK-TYPE: CDMA, GPRS or WLAN
Applicability of L2 Triggers
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Support of IPv4 Traversal of IPv6 Mobile Network
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From WLAN to CDMA, From CDMA to WLAN
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Main Idea
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Assumption
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Every WLAN subnet is IPv6 network.
Mobile router can connect to the IPv4 Internet
through CDMA interface.
Maintenance of IPv6 Connectivity through IPv6in-IPv4 Tunnel
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When mobile router becomes detached from IPv6
WLAN,
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it connects to IPv4 CDMA network and
it sets up an IPv6-in-IPv4 tunnel for IPv6 connectivity between its
home agent and itself.
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Mobile Router in NEMO
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IPv6 Mobile Router
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It has two IEEE 802.11g and one CDMA interfaces
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IEEE 802.11g Interfaces
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One is used as Ingress Interface and the other as Egress Interface.
802.11g supports bandwidth up to 54 Mbps.
It uses the 2.4 Ghz frequency for greater range.
CDMA(1x EV-DO) Interface
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It is used as Egress Interface.
CDMA 1xEV provide a peak rate data throughput of 2.4 Mbps.
•
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1x EV-DO of SKT provides actual speed of either 115 or 234 Kbps per one
user.
It uses a spectrally efficient 1.25 MHz channel.
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Service Scenarios in IPv6 NEMO
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NEMO should be able to maintain IPv6
connectivity b/w MNN & CN under a variety of
environments;
Property
Support
IP Version
WLAN
YES
IPv6
CDMA
YES
IPv4
Access Network
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Scenario 1 :
IPv6 Mobile Network connected to IPv6 Access Network
CN
Home Network
Home Link
CISCOSYSTEMS
HA
CISCOSYSTEMS
Internet
IPv6-in-IPv6
Tunnel
FN
CISCOSYSTEMS
AR1
(IPv6 WLAN)
Foreign Link
WLAN
FN
CDMA
MR
CISCOSYSTEMS
AR2
(IPv4 CDMA)
AR : Access Router
MR : Mobile Router
HA : Home Agent
MN : Mobile Node
FN : Fixed Node
CN : Correspondent Node
MN
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IPv6 Mobile Network
Scenario 2 :
IPv6 Mobile Network moving into IPv4 Access Network
CN
Home Network
Home Link
CISCOSYSTEMS
HA
CISCOSYSTEMS
Internet
FN
CISCOSYSTEMS
AR1
(IPv6 WLAN)
CISCOSYSTEMS
AR2
(IPv4 CDMA)
Foreign Link
WLAN
FN
CDMA
MR
MN
IPv6 Mobile Network
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Scenario 3 :
Setup of IPv6-in-IPv4 Tunnel
CN
Home Network
Home Link
CISCOSYSTEMS
HA
CISCOSYSTEMS
Internet
FN
CISCOSYSTEMS
AR1
(IPv6 WLAN)
IPv6-in-IPv4
Tunnel
CISCOSYSTEMS
AR2
(IPv4 CDMA)
Foreign Link
WLAN
FN
CDMA
MR
MN
IPv6 Mobile Network
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Auto-switching b/w WLAN & CDMA
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Switching Criteria
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MR prefers WLAN to CDMA.
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Signal strength from WLAN AP
Whenever WLAN is available, MR uses it rather than CDMA.
IPv4 Address Allocation during IPv4 Traverse
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IPv4 Address should be allocated for MR’s egress interface
through PPP’s IPCP (IP Control Protocol).
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IPv4 address should be public address.
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Roaming in IPv4 CDMA
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CDMA Connection Setup
 AAA Procedure in Linux
 IPv4 Address Allocation from PPP
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This address is used as Care-of Addres (CoA) of MIPv6.
When should MR set up CDMA session?
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Option 1 : Always from boot of MR
Option 2 : When WLAN is not available, MR starts to set up the session.
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Delay due to AAA procedure, IPv4 address allocation and IPv6-over-IPv4 tunnel setup
Management of IPv6-over-IPv4 Tunnel b/w HA & MR
 MIPv6’s Binding Update message is delivered to HA through IPv4
datagram.
 CDMA’s IPv4 address is represented as IPv4-Mapped IPv6 Address
Format and delivered to HA through Alternative Care-of Address in
Binding Update Message.
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IPv4 Datagram Layout for
IPv6-in-IPv4 Tunnel Management
IPv4 Header
Protocol = ICMP
DTMP Message Header
Home Address
Destionation Option Header
Mobility Header
Dynamic Tunnel Management Protocol
(DTMP) Message Format
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
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
.
.
.
Home Address Destination Option Header
.
.
.
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
.
.
.
Mobility Header
.
.
.
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
CDMA Interface’s IPv4 Address
represented as IPv4-Mapped IPv6 Address
Binding Update Message
Alternate Care-of Address = Mobile Router’s
IPv4 Address represented as IPv4-Mapped
IPv6 Address
80 bits
16 bits
32 bits
0000 . . . . . . . . . . . . . 0000
FFFF
IPv4 address
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Testbed for IPv6 NEMO
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We used NEMO Basic Support Protocol for
IPv6 Mobile Network.
For controlling network configuration,
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We control Tx and Rx power of IEEE 802.11g NIC.
Also, we use MAC-filtering to filter out packets in
other link.
We implemented IPv6 Wireless Mobile Router
based on embedded linux for testing Dynamic
Tunnel Management (DTMP) Protocol.
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Experiment of DTMP in
NEMO Testbed
Internet
Router
CDMA
WLAN
WLAN
CDMA
MR
IPv6 Wireless Mobile Router
MN
Test of DTMP
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Conclusion
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Policy for Fast Deployment of NEMO
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Current Status
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Dynamic Tunnel Management Protocol (DTMP)
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The current Internet consists mostly of IPv4 networks.
Cellular networks (e.g., CDMA and GPRS) can be used as
backup channel.
DTMP can support IPv4 Traversal of IPv6 Mobile Network in the
current Internet.
Future Work
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We will enhance our movement detection
mechanism in order to minimize packet loss
and delay of handover.
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