VINI: Virtual Network Infrastructure

1. VINI: Virtual Network Infrastructure Jennifer Rexford Princeton University http://www.cs.princeton.edu/~jrex

2. The Internet: A Remarkable Story • Tremendous success • From research experiment to global communications infrastructure • The brilliance of under-specifying • Best-effort packet delivery service • Key functionality at programmable end hosts • Enabled massive growth and innovation • Ease of adding hosts and link technologies • Ease of adding services (Web, P2P, VoIP, …) • But, change is easy only at the edge… 

3. Rethinking the Network Architecture • But, the Internet is showing signs of age • Security, mobility, availability, manageability, … • Challenges rooted in early design decisions • Weak notion of identity, tying address & location • Not just a matter of redesigning a single protocol • Revisit definition and placement of function • What are the types of nodes in the system? • What are their powers and limitations? • What information do they exchange?

4. Hurdle #1: Deployment Dilemma • An unfortunate catch-22 • Must deploy an idea to demonstrate feasibility • Can’t get an undemonstrated idea deployed • A corollary: the testbed dilemma • Production network: real users, but can’t change • Research testbed: easy changes, but no users • Bad for the research community • Good ideas sit on the shelf • Promising ideas do not grow up into good ones

5. Hurdle #2: Too Many Design Goals • Many different system-engineering goals • Scalability, reliability, security, privacy, robustness, performance guarantees, … • Perhaps we cannot satisfy all of them at once • Applications have different priorities • Online banking: security • Web surfing: privacy, high throughput • Voice and gaming: low delay and loss • Compromise solution isn’t good for anyone

6. Hurdle #3: Coordination Constraint • Difficult to deploy end-to-end services • Benefits only when most networks deploy • No single network wants to deploy first • Many deployment failures • QoS, IP multicast, secure routing, IPv6,… • Despite solving real, pressing problems • Increasing commoditization of ISPs 1 2 3 sender receiver

7. Virtualization to the Rescue • Multiple customized architectures in parallel • Multiple logical routers on a single platform • Isolation of resources, like CPU and bandwidth • Programmability for customizing each “slice”

8. Overcoming the Hurdles • Deployment Dilemma • Run multiple experimental networks in parallel • Some are mature, offering services to users • Isolated from others that are works in progress • Too Many Design Goals • Run multiple operational networks in parallel • Customized to certain applications and users • Coordination Constraint • Run multiple end-to-endservices in parallel • Over equipment owned by different parties

9. Three Projects: GENI, VINI, CABO • Global Environment for Network Innovations • Large initiative for a shared experimental facility • Jointly between NSF CISE division & community • Distributed systems, wireless, optics, backbone • VIrtual Network Infrastructure • Baby step toward the design of GENI • Systems research on network virtualization • Concurrent Architectures Better than One • Clean-slate architecture based on virtualization • Economic refactoring for end-to-end services See http://www.geni.net and http://www.vini-veritas.net

10. VINI: VIrtual Network Infrastructure

11. Traffic Synthetic or traces Real clients, servers Arbitrary, emulated Actual network Topology Inject faults, anomalies Observed in operational network Network Events VINI Offers “Controlled Realism” Synthetic or traces Real clients, servers • Start with a controlled experiment • Relax constraints, study effects • Result: an operational virtual network that’s • Feasible • Valuable • Robust • Scalable, etc. Traffic

12. Fixed Infrastructure Deployed VINI nodes in National Lambda Rail and Abilene, and PoPs in Seattle and Virginia

13. Shared Infrastructure Experiments given illusion of dedicated hardware

14. Flexible Topology VINI supports arbitrary virtual topologies

15. Network Events VINI exposes, can inject network failures

16. c External Connectivity s Experiments can carry traffic for real end-users

17. BGP BGP c BGP BGP External Routing Adjacencies s Experiments can participate in Internet routing

18. VINI Platform Design

19. Virtualizing the Computer • Starting with the PlanetLab software • Each experiment has its own virtual machine • Each has “root” in its own VM, can customize • Reserve processing resources per VM Node Mgr Local Admin VM1 VM2 VMn … Virtual Machine Monitor (VMM) (Linux++) PlanetLab node

20. Creating the Virtual Topology • Goal: real routing protocols on virtual network topologies • Various routing protocols (BGP, OSPF, RIP, IP multicast) • Run unmodified routing software in a virtual machine XORP (routing protocols) VM

21. Virtual Network Abstraction • PlanetLab limitation: • Does not virtualize the underlying network • For each VM we want • Interfaces, bound to tunnels to other nodes • Networking stack (e.g., forwarding table) • Packet forwarding in OS • Across VMs we want • Independent topologies • Resource isolation User space XORP (routing protocols) eth0 eth1 eth2 eth3 Control Data FIB tunnels OS

22. Network Name Spaces (NetNS) • NetNS extension to Linux • Virtualizes the network stack • Each network stack bound to user process(es) • Provides us with • Separate forwarding table (FIB) • Separate interfaces • But, a few challenges remain • Connecting interfaces to tunnels • Supporting non-IP protocols • Providing isolation between virtual nodes

23. Connecting Interfaces to Tunnels • Ethernet switch • Linux bridge module • Connects all interfaces • And all tunnels • Short bridge • No MAC learning • No forwarding look-up • No frame header copying • EGRE tunnels • Carry Ethernet frames • Support non-IP protocols User space XORP (routing protocols) eth0 eth1 eth2 eth3 etun1 etun3 etun2 FIB Short Bridge OS

24. Isolation Between Virtual Networks • Virtual host (user space) • Experimenter’s software • Protocols, applications • Virtual host (OS) • Forwarding tables • Virtual Ethernet interfaces • Shared substrate (OS) • Tunnels between nodes • Enforcing rate limits User space XORP (routing protocols) eth0 eth1 eth2 eth3 etun1 etun3 etun2 FIB OS Short Bridge OS

25. Ongoing Work on Packet Forwarding • Tension between three goals • High-speed packet forwarding • Customization of the data plane • Sharing of the data plane • Step #1: Greater flexibility • Customized data planes in the kernel • Virtualizing Click to support different virtual hosts • Step #2: Greater speed • Customized data planes in an FPGA • Virtualizing the NetFPGA board from Stanford

26. Example Experiment on VINI

27. Intra-domain Route Changes s 2095 856 700 260 233 1295 c 639 548 366 846 587 902 1893 1176 Watch OSPF route convergence on Abilene

28. Link down Link up Routes converging Abilene RTT: 73ms Ping During Link Failure

29. Link down Link up Zoom in TCP Throughput

30. Slow start Retransmit lost packet Arriving TCP Packets VINI enables a virtual network to behave like a real network

31. Other Example VINI Experiments • Scaling Ethernet to a large enterprise • Routing-protocol support for mobile hosts • Network-layer support for overlay services • Piggybacking diagnostic data on packets • <Insert your prototype system here> • Multiple solutions to multiple problems…

32. Where does all this experimentation lead us?

33. The Case for Pluralism • Suppose we can break down the barriers… • Enable realistic evaluation of new ideas • Overcome the coordination constraint • Maybe there isn’t just one right answer • Maybe the problem is over-constrained • Too many goals, some of them conflicting • Maybe the goals change over time • And we’ll always be reinventing ourselves • The only constant is change • So, perhaps we should design for change

34. Different Services, Different Goals • Performance • Low delay/jitter: VoIP and online gaming • High throughput: bulk file transfer • Security/privacy • High security: online banking and e-commerce • High privacy: Web surfing • Scalability • Very scalable: global Internet reachability • Not so scalable: communication in small groups

35. Applications Within an Single ISP • Customized virtual networks • Security for online banking • Fast-convergence for VoIP and gaming • Specialized handling of suspicious traffic • Testing and deploying new protocols • Evaluate on a separate virtual network • Rather than in a dedicated test lab • Large scale and early-adopter traffic • Leasing virtual components to others • ISPs have unused node and link capacity • Can allow others to construct services on top

36. Economic Refactoring in CABO • Infrastructure providers:Maintain routers, links, data centers, and other physical infrastructure • Service providers:Offer end-to-end services (e.g., layer 3 VPNs, SLAs, etc.) to users Infrastructure Providers Service Providers Today: ISPs try to play both roles, and cannot offer end-to-end services

37. Similar Trends in Other Industries • Commercial aviation • Infrastructure providers: Airports • Infrastructure: Gates, “hands and eyes” support • Service providers: Airlines JFK SFO PEK ATL E.g.: airplanes, auto industry, and commercial real estate

38. Broker Communications Networks, Too! • Two commercial examples in IP networks • Packet Fabric: share routers at exchange points • FON: resells users’ wireless Internet connectivity • FON economic refactoring • Infrastructure providers: Buy upstream connectivity • Service provider: FON as the broker(www.fon.com)

39. Enabling End-to-End Services • Secure routing protocols • Multi-provider Virtual Private Networks • Paths with end-to-end performance guarantees Today Cabo Competing ISPs with different goals must coordinate Single service provider controls end-to-end path

40. Conclusion • The Internet needs to change • Security, mobility, availability, management, … • We can overcome barriers to change • Enable realistic experimentation with new ideas • Enable multiple designs with different trade-offs • Enable end-to-end deployment of new services • Network virtualization is the key • Run many research experiments in parallel • Offer customized end-to-end services in parallel • VINI as an enabling experimental platform