1. Flexible Traffic Engineering: When OpenFlow Meets Multi-Protocol IP- Forwarding IEEE COMMUNICATIONS LETTERS, VOL. 18, NO. 10, OCTOBER 2014 Authors: Suoheng Li ; Yan Shao ; Shoujiang Ma ; Nana Xue ; Shengru Li ; Daoyun Hu ; Zuqing Zhu University of Science and Technology of China, Hefei, China 1

2. Outline IPv6 transition technologies Motivation System architecture System operation procedure Evaluation Conclusion Personal opinion Reference 2

3. IPv6 transition technologies: 3 Dual stack Allow IPv4 and IPv6 to cTunnel Enable network edge devices to interconnect over incompatible networks. o-exist in the same devices and networks. Address translation Allow IPv6-only devices to communicate with IPv4-only devices.

4. Motivation IPv6 transition technologies lack of a Flexible Traffic Engineering (F-TE). IP transition technique that only makes IPv4- and IPv6-devices inter-operable is not enough for realizing F-TE, since it only pre-configures IP tunnels statically and cannot establish/disassemble them on-the-fly. 4 IPv4 island IPv6 island IPv4 island Client A Client B IPv6 island GW

5. System architecture 5 Using OpenFlow switch as these islands’ gateway.

6. System operation procedure 6 Network management system (NMS) Path provision module (PPM) Path computation module (PCM) Address translation database (ATD) Traffic engineering database (TED) open shortest path first (OSPF) Simple network management protocol (SNMP)

7. Evaluation (a)Without TE 2 → 1 → 9 7

8. Evaluation (b)Conventional TE Path switching for TE is possible but IP interchanging is not allowed 2→1→8→9/2→ 4 → 11 → 13 → 9 8

9. Evaluation (c)TE with static IP-in-IP tunnel tunnel (ST) 2→1→8→9 2→ 3 →( 6 → 5 → 7) → 8 → 9 9

10. Evaluation (d)F-TE 2→ 3 → 6 → 5 → 7 →8 →9 10

11. Evaluation 11

12. Conclusion This mechanism achieve F-TE in a network that consists of multiple IPv4- and IPv6-islands with online and adaptive IP-forwarding interchanging enabled by OF. The SDN-enabled IP interchanging architecture presented in this work could also facilitate seamless transition from IPv4 to IPv6. 12

13. Personal opinions: The authors mentioned that they design five new OF flow-matching actions, namely PUSH_ IPv6, POP_IPv6, MOD_IPv6, PUSH_IPv4, and POP_IPv4. It is a good idea if OpenFlow support these action to make us easy to modify IP layer headers. But it is not a standard at all, now. In the evaluation chapter, they only used one picture to illustrator four scenarios, it make people hard to understand. 13

14. Reference RFC 6219 X. Li, C. Bao, M. Chen, H. Zhang, and J. Wu, The China Education and Research Network (CERNET) IVI Translation Design and Deployment for the IPv4/IPv6 Coexistence and Transition, May 2011 RFC 6219. http://en.wikipedia.org/wiki/Teletraffic_engineering 14