1 In VINI Veritas: Realistic and Controlled Network Experimentation Jennifer Rexford with Andy Bavier, Nick Feamster, Mark Huang, and Larry Peterson

2 How to build a backbone network with programmable components and share it with others…

3 Challenges Facing the Internet Fundamental challenges –Security –Network management –Quality of service –Scalability –…–… Many promising research directions –Realistic evaluation of the existing protocols –Design of incrementally-deployable extensions –Creation of new network architectures

4 This chasm is a major barrier to Future Internet development VINI: Bridging the Gap Maturity Time Foundational Research Research Prototypes Small Scale Testbeds Deployed Future Internet Experimental network facility

5 Goals of Virtual Network Infrastructure Running real router software “as is” –Open-source and commercial router code Carrying real traffic from end hosts –Application traffic from hosts, including real users Exposing realistic network conditions –Network failures and routing messages from neighbors Controlling network events –Injecting link and node failures in a controlled fashion Sharing across multiple simultaneous experiments –Amortizing the cost of building the infrastructure

6 Network Infrastructure Network topology –Points of Presence –Link bandwidth –Upstream connectivity Two backbones –Abilene Internet2 –National Lambda Rail

7 Building Virtual Networks Physical nodes –Initially, high-end computers –Later, network processors and FPGAs Virtual routers (a la PlanetLab) –Multiple virtual servers on a single node –Separate shares of resources (e.g., CPU, bandwidth) –Extensions for resource guarantees and priority

8 Building Virtual Links Creating the illusion of interfaces –Create a tunnel for each link in the topology –Assign IP addresses to the end-points of tunnels –Match tunnels with one-hop links in the real topology

9 Building Multiple Virtual Topologies Separate topology per experiment –Routers are virtual servers –Links are a subset of possible tunnels Creating a customized environment –Running User Mode Linux (UML) in a virtual server –Configuring UML to see multiple interfaces –Enables running the routing software “as is” Operating System RRRRR

10 Overcoming Efficiency Challenges Packet forwarding must be fast –But, we are doing packet forwarding in software –And don’t want the extra overhead of UML Solution: separate packet forwarding –Routing protocols running within UML –Packet forwarding running outside of UML UML Click XORP XORP: routing software Click: forwarding software

11 Carrying Real User Traffic Users opt in to VINI –User runs VPN client –Connects to VINI node External Internet hosts –VINI connects to Internet –Apply NAT at boundary UML Click Client Server UDP tunnels XORP Open VPN Network Address Translation routing-protocol messages VINI

12 Example VINI Experiment Configure VINI just like Abilene –VINI node per PoP –VINI link per inter-PoP link –Routing configuration as real routers Network event –Inject link failure between two PoPs –… in midst of an ongoing file transfer Measuring routing convergence –Packet monitoring of the data transfer –Active probes of round-trip time & loss –Detailed view of effects on data traffic

13 VINI Current Status Initial Abilene deployment –Eleven sites –Nodes running XORP and Click on UML Upcoming deployment –Six sites in National Lambda Rail –… with direct routing-protocol sessions with routers –Dedicated bandwidth between Abilene sites In the works –Upstream connectivity via a commercial ISP in NYC –Speaking interdomain routing with the Internet

14 Global Environment for Network Innovations GENI –Major new National Science Foundation initiative –Infrastructure for evaluating clean-slate architectures ISP 1 ISP 2 PC Clusters Programmable Routers Wireless Subnets Optical Switches

15 VINI as a Step Toward GENI GENI has a much broader scope –Programmable hardware routers –Flexible control of the optical components –Wireless and sensor networks at the edge VINI as strawman design of GENI backbone –Multiple network experiments in parallel –Connections to end users and upstream providers –Supporting Internet protocols and new designs VINI as an initial experimental platform –Support researchers doing network experiments –… while completing GENI design and deployment