1. Dynamic Tunnel Management Protocolfor IPv4 Traversal of IPv6 Mobile Network Jaehoon Jeong Protocol Engineering Center, ETRI paul@etri.re.kr http://www.nemo.6ants.net/ VTC 2004 Fall

2. Contents • 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 forIPv6-in-IPv4 Tunnel Management • Testbed for IPv6 NEMO • Conclusion

3. Motivation • Network Mobility (NEMO) Basic Support protocol • Object of NEMO • NEMO allows a mobile network reachable in the Internet through Mobile IPv6 Extension. • NEMO is being developed at IETF NEMO working group • Limitation of Current NEMO Protocol • NEMO supports network mobility only in IPv6 Internet through bi-directional tunneling between Mobile Router (MR) and Home Agent (HA). • Goal of This Paper • Support of IPv4 Traversal of IPv6 Mobile Network in the current Internet that consists nearly of IPv4 networks.

4. Network Mobility (NEMO) – 1/2 • Role of NEMO Protocol • Session Continuity of Mobile Network Node (MNN) • Connectivity of MNN • Reachability of MNN • Location Management • Key Idea of NEMO • HA forwards data packets destined for Mobile Network. • HA maintains the forwarding information related to Mobile Network Prefix(es).

5. Network Mobility (NEMO) – 2/2 • Management of Mobile Network Prefix • Binding Update of Implicit Mode • Binding Update of Explicit Mode • Dynamic Routing Protocols • Refer to NEMO draft for detailed information • draft-ietf-nemo-basic-support-03.txt

6. Related Work • Vertical Handover based on L2 Triggers • Vertical Handover • Handover between different kinds of physical networks • L2 Trigger • An event that occurs at the Link Layer that is forwarded to the upper layer, i.e., Layer 3. • Five L2 triggers were proposed: • Link Up, Link Down, Source Trigger, Target Trigger or Mobile Trigger • L2 Hint • Information that can be optionally transported with an L2 trigger • LINK-TYPE: CDMA, GPRS or WLAN • Applicability of L2 Triggers • Support of IPv4 Traversal of IPv6 Mobile Network • From WLAN to CDMA, From CDMA to WLAN

7. Main Idea • Assumption • Every WLAN subnet is IPv6 network. • Mobile router can connect to the IPv4 Internet through CDMA interface. • Maintenance of IPv6 Connectivity through IPv6-in-IPv4 Tunnel • When mobile router becomes detached from IPv6 WLAN, • it connects to IPv4 CDMA network and • it sets up an IPv6-in-IPv4 tunnel for IPv6 connectivity between its home agent and itself.

8. Mobile Router in NEMO • IPv6 Mobile Router • It has two IEEE 802.11g and one CDMA interfaces • IEEE 802.11g Interfaces • 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 • It is used as Egress Interface. • CDMA 1xEV provide a peak rate data throughput of 2.4 Mbps. • 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.

9. Service Scenarios in IPv6 NEMO • NEMO should be able to maintain IPv6 connectivity b/w MNN & CN under a variety of environments;

10. Scenario 1 :IPv6 Mobile Network connected to IPv6 Access Network

11. Scenario 2 :IPv6 Mobile Network moving into IPv4 Access Network

12. Scenario 3 :Setup of IPv6-in-IPv4 Tunnel

13. Auto-switching b/w WLAN & CDMA • Switching Criteria • Signal strength from WLAN AP • MR prefers WLAN to CDMA. • Whenever WLAN is available, MR uses it rather than CDMA. • IPv4 Address Allocation during IPv4 Traverse • IPv4 Address should be allocated for MR’s egress interface through PPP’s IPCP (IP Control Protocol). • IPv4 address should be public address.

14. Roaming in IPv4 CDMA • CDMA Connection Setup • AAA Procedure in Linux • IPv4 Address Allocation from PPP • This address is used as Care-of Addres (CoA) of MIPv6. • When should MR set up CDMA session? • Option 1 : Always from boot of MR • Option 2 : When WLAN is not available, MR starts to set up the session. • 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.

15. IPv4 Datagram Layout forIPv6-in-IPv4 Tunnel Management Dynamic Tunnel Management Protocol (DTMP) Message Format CDMA Interface’s IPv4 Addressrepresented as IPv4-Mapped IPv6 Address

16. Testbed for IPv6 NEMO • We used NEMO Basic Support Protocol for IPv6 Mobile Network. • For controlling network configuration, • 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.

17. Experiment of DTMP inNEMO Testbed IPv6 Wireless Mobile Router Test of DTMP

18. Conclusion • Policy for Fast Deployment of NEMO • Current Status • The current Internet consists mostly of IPv4 networks. • Cellular networks (e.g., CDMA and GPRS) can be used as backup channel. • Dynamic Tunnel Management Protocol (DTMP) • DTMP can support IPv4 Traversal of IPv6 Mobile Network in the current Internet. • Future Work • We will enhance our movement detection mechanism in order to minimize packet loss and delay of handover.