Hidetoshi Yokota KDDI Lab Sri Gundavelli Cisco Kent Leung Cisco

1. Inter-technology handoff support in mobile mode for Proxy Mobile IPv6<draft-yokota-netlmm-pmipv6-mn-itho-support-02> Hidetoshi Yokota KDDI Lab Sri Gundavelli Cisco Kent Leung Cisco IETF #76 Hiroshima

2. Problem space • A variety of mobile terminals are emerging with multiple interfaces for different access technologies • Smartphone, UMPC, MID • A variety of OSs are assumed on the terminal • Windows, Linux, FreeBSD, etc. • Proxy Mobile IPv6 (RFC5213) is supported by the mobile network to support mobility between those access technologies • This is not just enough in many cases…

3. Virtual interface as a solution • The use of virtual interface in host architectures has been a common practice for many years • The use of virtual interface has many use cases and the inter-tech handoff in mobile architectures is a useful one • The scope of the work is to document this known practice • MIF WG should capture this aspect

4. MAG1 IP1 IF1 MN-ID MAG2 IP2 IF2 MN-ID LMA MAG1 MAG2 IF1 IF2 IP1 IP2 MN MN ID (b) Multi-homing Handoff and multi-homing from the perspective of PMIPv6 • Handoff: same address is assigned at a new proxy binding update • Multi-homing: different addresses are assigned at a new proxy binding update MAG12 IP1 IF1->IF2 MN-ID LMA MAG1 MAG2 IP1 IF1 IF2 MN MN ID (a) Inter-technology HO

5. Timing of handoff • T1 is the time when IF1 is detached or deactivated • T2 is the time when IF2 is attached or activated IF1 IF2 (a) t T1 < T2 IF1 IF2 (b) t T1 = T2 IF1 (c) IF2 t T2 < T1

6. Relationship between IP session and the interface (tight coupling) • If IP address is bound to a physical address, the IP session could be disconnected even if the same address is assigned Application Application layer [Socket I/F] TCP/UDP Transport layer IP stack (IPv4/IPv6) IP layer Datalink layer IP1 IP1 I/F “ppp0” I/F “wmx1” EVDO WiMAX Physical layer

7. Relationship between IP session and the interface (loose coupling) • If IP address does not have one-to-one mapping with a physical interface, the IP session may be maintained even if the interface is changed Application Application layer [Socket I/F] TCP/UDP Transport layer IP1 IP stack (IPv4/IPv6) IP layer Datalink layer I/F “ppp0” I/F “wmx1” EVDO WiMAX Physical layer

8. Virtual interface for interworking (3) Application Communication Manager Application layer TCP/UDP Transport layer IP stack (IPv4/IPv6) IP layer (1) Virtual interface Datalink layer (2) I/F I/F Physical layer EVDO WiMAX Necessary software for interwork

9. Functional overview of additional software and interfaces • Communication Manager • Management and switching of wireless devices, provision of user interface • Virtual Interface • A virtual device to make multiple devices appear to be one device from the IP layer (driver software) • Interface (1) • Controls the switching of physical devices • Interface (2) • Retrieves wireless conditions (e.g. signal strength) • Turns the devices on and off • Interface (3) • Configures the threshold of the signal strength or preferred interface

10. Summary and proposal • Clarification of necessary functionalities for interworking • How the virtual interface is involved with the physical interfaces and applications through the IP stack • IP address binding to the virtual interface, IPv6 ND on the virtual interface and physical interface works as a bridge • Documentation of guidelines • MIF WG should capture the aspect of inter-technology handoff and identify the virtual interface works as a common practice