Topology and Flow Management in Multi-Controller OpenFlow Networks

1. Topology and Flow Management in Multi-Controller OpenFlow Networks  Dr. Te-Lung Liu Research Fellow NCHC, NARLabs

2. Multi-Controller OpenFlow Networks • OpenFlow differs from traditional networks by separating Control and Data Path • Openflow controller has global view of the network for software-controlled routing decisions • Routing protocols that periodically exchange information among network devices are no longer needed • Routing decisions are fast and accurate (no convergence time and hop-by-hop decisions) • However, only single controller scenario is available currently • For large-scale network or inter-DC environment, single controller poses performance problem 2

5. Multi-Controller OpenFlow Networks • Multi-controller scenario would be a proper solution for large-scale OpenFlow networks • But OpenFlow lacks of inter-controller communication mechanisms • Controllers decide routes in its own domain separately • Inter-controller flow could be made by connecting partial flows provisioned by controllers of each domain • Lack of global view for inter-controller flows • Difficult to support QoS or SLA functions across controllers • Inter-domain topology auto-discovery is required for multi-controller management • We modify the LLDP and BDDP so that both NOX and Floodlight can discover each other • Moreover, we can trace realtime host-to-host flows with global information 5

6. TWAREN OpenFlow Testbed in 2010 iGENI NCHC Capsulator TWAREN L3 Network NOX OpenFlow Network @KUAS OpenFlow Network @NCKU Capsulator Capsulator OpenFlow Switch • NCKU and KUAS are pilot universities that connected with the Testbed • The OpenFlow Testbed is extended to iGENI@iCAIR • Capsulator (Ethernet-in-IP tunnel) is used to emulate pure L2 network for OpenFlow 6

7. NCTU NIU Capsulator NCU NARLabs/NCHC lightpath TWAREN VPLS Capsulator NCKU CHT-TL KUAS NTUST SURFnet Capsulator TWAREN OpenFlow Testbed now OpenFlow Switch OpenFlow Switch OpenFlow Switch OpenFlow Switch OpenFlow Switch OpenFlow Switch OpenFlow Switch OpenFlow Switch OpenFlow Switch OpenFlow Switch • NTUST, NCU, NIU, NCTU and CHT-TL joined the Testbed. • For TWAREN connectors (NCTU, NCKU, KUAS and NCU), a dedicated VPLS VLAN is allocated for better transmission performance. • Extended International connections with JGN-X and SURFnet 7

8. VLAN Setup for OpenFlow NCU iCAIR-Chicago OF-SW NCU-7609V Vlan 560 CHI-15454 NCTU Vlan 2782 Vlan 563 OF-SW NCTU-7609V OF-SW KUAS Vlan 555 (Q-in-Q) Vlan 1555 TWARENVPLS VPN TWARENInternational Lightpath Vlan 2782 OF-SW KUASRouter NSYSU-7609V Vlan 548 (Q-in-Q) NCKU Vlan 2782 Vlan 1548 TN-15454 NCKU-7609P NCKU-7609V OF-SW Capsulator Vlan 2782 NTUST CHT-TL Trunk Trunk OF-SW TN-7609V TN-7609P NARL/NCHC OF-SW OF-SW Capsulator 8

9. iGENI - Taiwan Integrated Research Network 9

10. Inter-Domain Topology Discovery (I) • OpenFlow Controller just only knows its directly connected switches. • ENVI is a useful GUI tool to show OpenFlow topology under single controller. OFA OFB OFC OFD Controller1 Controller2 Domain UI Topology of Domain1 Topology of Domain2 OFA OFB OFC OFD 10

11. Inter-Domain Topology Discovery (II) OFA OFB OFC OFD Controller1 Controller2 Domain UI Topology of Domain1 & 2 OFA OFB OFC OFD • We add additional contents in LLDP (Link Layer Discovery Protocol) packet to let Controllers have its neighbors’ connectivity details. • ENVI is also modified to show the whole topology. 11

12. Inter-Domain ENVI Flow Viewer(IEFV) The function of I.E.F.V are as follows: 1.It can display Flow, Flow number, and Flow information. 2.It can support multi-connection to communication with all NOXs. 3.It can get all topology information to display Inter-domain nodes. 4.It cans how IP address of NOX controlling this node ENVI 12

13. Our modification OF s/w 1 OF s/w 2 ＊Our modifications are marked in red color. CL B CL A 4. Reply new topology information (includung other inter-domain NOXes) 2. Set new topology and client position OF S/W1 3. Request topology information from NOX input by user CL A(client) NOX1 1. CLA send flow 7. Merge all topology messages and show it NOX2 5. Request topology information from next NOX I.E.F.V 2. Set new topology and client position OF S/W2 CL B(client) OF s/w 1 OF s/w 2 6. Reply new topology information CL B CL A 13

14. Sample Topology Flow1 Flow2 14

15. The digits indicate the number of flows over the link NOX2 Domain NOX1 Domain When mouse moves over the link, this panel shows the flow information over this link. NOX3 Domain Results 15

16. North Part South Part SC13 Demo NTUST CHT-TL SurfNet iCAIR NCU NARLabs/NCHC NIU NCTU NARLabs/NCHC JGNX NCKU

17. North Part Topology NTUST SurfNet iCAIR CHT-TL NARLabs/NCHC

18. South Part Topology NIU NCU JGNX NCTU NARLabs/NCHC NCKU

19. The flow information will be shown here When clicking these flows The Host-to-host path of selected flow is highlighted

20. Conclusion • For large-scale OpenFlow networks and collaborations among different research institutes or countries, multi-controller scenario is well-suited • Our modifications to NOX/ENVI could discover network topology automatically and provide real-time flow observation over mutli-controller networks. • We will continue to explore Inter-domain management and other functions (e.g. IPv6) to support the testbed maintenance 20

21. SDN Developing Trends

22. App App App Windows (OS) Linux Mac OS Windows (OS) Linux Mac OS Windows (OS) Linux Mac OS Virtualization layer x86 (Computer) Computer Industry Industry Trends… App App App Controller 1 Controller 2 Controller 1 Controller 2 NOX (Network OS) Network OS Virtualization or “Slicing” OpenFlow Network Industry Slide from Nick McKeown@Stanford

23. From:”Shougaku Ninensei” Magazine Issue on Jan. 1979

24. Thank You ! 24