1. Dynamic Tunneling Configuration for Network with Uni-Directional Link ICCC99 – 15/09/1999 Mikiyo NISHIDA / KEIO Univ. Hiroyuki KUSUMOTO / KEIO Univ. Jun MURAI / KEIO Univ.

2. General Description Introdunction –Characteristics of Uni-Directional Link Current Problems of Uni-Directional Link Scheme –Dynamic Tunneling Configuration Design –Message based mechanism Implementation –Implement our mechanism Conclusion

3. Introduction(1) UDL Uni Directional Link –One-way (most case:Multiple Access)data link Satellite Cable TV

4. Introduction(2) Network with UDL Network with UDL & BDL (Bi- Directional Link) –We assume UDL network in the Internet has UDL and another BDL accessibility

5. Introduction(3) Tunneling Techniques For Simulating link solution –tunneling Current Tunneling Scheme –Static Configuration –Few Scalability –Too much management cost We propose ‘ Dynamic Tunnel Configuration Scheme’

6. Current Problems(1) Routing in network with UDL Current Internet Routing Protocol –Based on Link Bi-directonality Approaches for using UDL network –Modify Routing Protocol –Provide Bi-Directional accessibility for UDL virtually

7. Current Problems(2) Data-link address resolution in UDL Multiple access data-link requires data-link address resolution –Ethernet use ARP protocol

8. Current Problems(3) IP Address Assignment in UDL UDL has a lot of receivers IP address is limited resource

9. Current Problems - Overall Routing Problems Data-link address resolution IP Address Assignment

10. Dynamic Tunneling Scheme(1) We propose Dynamic Tunneling Configuration Scheme –Provide virtual return path of UDL automatically –Provide mechanism of data-link address resolution on UDL –Provide mechanism of IP address dynamic assignment

11. Dynamic Tunneling Scheme(2) Message based mechanism –Exchange messages over UDL and BDL –UDL Keepalive –Setup/Shutdown tunnel –Data-link address resolution –IP Address Automatically Assignment

12. Design(1) General Description

13. Design(2) Messages Notify Message (via UDL) –Sender to Receiver HELLO message –Notify Sender Information –Applied UDL Keep Alive

14. Design(3) Messages Control Message (via BDL) –Exchange each other REQUEST Message (Receiver to Sender) –Notify Receiver beginning to use UDL –Request Tunnel Setup, IP Address Assign REPLY Message (Sender to Receiver) –Reply for Receiver’s message REFRESH/RELEASE Message (Receiver to Sender) –Notify Receiver uses UDL continuously / terminate using UDL

15. Design(4) Modules Virtual Link Module –Manipulate tunneling packets Control Module –Manipulate messages –Set/Release tunnel –Set/Release interface’s IP address –Maintain IP/DL address

16. Design(5) Operating cycle

17. Implementation(1) Target Architecture: – FreeBSD 2.2.1-Release Modified data-link routine in Unix Kernel UDL: Use Ethernet (Modified Output Routine) BDL: Use Ethernet Virtual Link Module is implemented in Unix Kernel Control Module is implemented as user process application

18. Implementation(2) Virtual Link Module Total of 120 lines: –if_ethersubr.c ether_input(), ether_output() Add encapsulation/decapsulation function –if.c if_ioctl() Add manipulating tunnel information function

19. Implementation(3) Control module Code size –Total of 1450 lines / at Receiver –Total of 1436 lines / at Sender Implement as user process application Send and receive messages via UDP Maintenance DL/IP address table

20. Conclusion Describe current problems of network with unidirectional link Propose Dynamic Tunnel Configuration Scheme Implement our proposed mechanism Present usability of this scheme

21. Future Work Test many types of routing protocols Improve performance and scalability