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Try Before you Buy:SDN Emulation with (Real) Interdomain RoutingBrandon Schlinker⋆, Kyriakos Zarifis*, Italo Cunha♮, Nick Feamster †,Ethan Katz-Bassett*, and Minlan Yu*

University of Southern California, California, USA⋆

Universidade Federal de Minas Gerais, Minas Gerais, Brazil♮

Georgia Institute of Technology, Georgia, USA†

Open Networking SummitSanta Clara, California, USAMarch 2014

SDN Presents New Questions for Network Operators

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Questions in Legacy Networks: Protocol(s) to Use

Internal Routing (IGPs: OSPF, RIP)

Scalability BGP scalability

Equipment Vendor Single CLI Support for vendor-specific technologies

SDN uses centralized controller to make decisions and focuses on forwarding, not routing

Controller scalability, switch performance

Controller capabilities, interoperability

Questions in SDN Networks:

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SDN Creates New Challenges for Operators

For a Network Operator, SDN = New interactions New components that require redundancy New scalability and management issues

How Does SDN Impact my Network?

Overwhelmed Network Operator

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New Data Centers: Great Environments for Deploying SDN

Greenfield environment – all new equipment purchased at once Homogeneous network -- 100% SDN infrastructure Built from the ground-up, no risk of downtime during setup One administrative domain, little interaction with other networks

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What about existing ISP and Enterprise Networks?

ISP Backbone Network

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Existing Networks Built Piecemeal Over Multiple Years

Provider Started at East Coast with One Equipment Vendor

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Existing Networks Built Piecemeal Over Multiple Years

Expanded to West Coast With Different Equipment Vendor

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Multiple Technologies Support Large Networks

Different Technologies Used Across Existing Network Different IGPs (OSPF, RIP), Route Reflectors for BGP scalability, Middleboxes Company acquisitions, sudden growth, vendor specific technologies → heterogeneity

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Large Networks Have Interactions with Other Networks

Multiple Points of Presence for Interacting with Other Networks Interactions will continue to use BGP protocol for foreseeable future (even with SDN) These interactions are important → they define internal traffic patterns

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Other Existing Networks Have Similar Problems

Other Networks May Not Be As Large, But Will Face Similar Problems ISPs, Enterprise Networks, Educational Networks, Service Providers

Highly Diverse Network Ecosystem Lots of custom configurations, protocols, hidden interactions, outdated decisions Opposite of environment typically discussed when we talk about SDN

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Realities of Transitioning to SDN

Takes time to migrate existing networks Some operators not ready to migrate portions of their network to SDN technologies

BGP isn’t going away soon (still need to interconnect the Internet)

Need Hybrid Network for Foreseeable Future Need to ensure different technologies in hybrid network play nice

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Network Operators….

How Does an Operator Make Sure SDN Plays Nice In Their Existing Network?What Tools Can These Use To Understand SDN’s Impact?

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Mininet Enables Emulation of SDN Networks

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Mininet Lacks Support for Emulating Existing Networks…

Lacks Emulation Support for Key Components in Today’s Networks: Inter-domain routing (BGP between multiple AS) Intra-domain routing (Legacy IGPs, such as OSPF, RIP)

Cannot support hybrid networks

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Emulation Limited Regardless of Emulator

Cannot accurately emulate peer ISPs: Unpredictable routes, failures, policies, topologies, business & technical goals

We need more than emulation...

Impossible to Emulate

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MiniNExT

Comprehensive Network Emulation of Intra-domaincombined with

Inter-domain Connectivity with Real Networks

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MiniNExT’s Extends Mininet’s Emulation Support

Extends Mininet to Support BGP and IGP Protocols Now can support any network type, including hybrid networks Requires significantly less resources than emulation with virtual machines

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[Real] [Emulated]

MiniNExT Goes Beyond Emulation with Real Connectivity

Combines Emulated Network with Real BGP Connectivity Multiplexes a real network’s existing BGP sessions Enables emulated and operational network to communicate with peers via BGP

BGP Sessions Multiplexed toProvide Real Connectivity

Emulated with

MiniNExT

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MiniNExT Translates Network 1:1 into Sandbox Environment

Real Network

MiniNExTSandbox

Both networks can run at the same time

MiniNExTTranslation

Emulated with MiniNExT on a laptop

MiniNExT Combines Emulated Network with Real BGP

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Real BGP Sessions

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MiniNExT Enables SDN Experiments

Let’s Change The Data Center Network to SDN

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MiniNExT Enables SDN Experiments

New SDN Data Center (All Other Components The Same)

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MiniNExT Emulated Networks Can Exchange Routes, Traffic

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MiniNExT Helps Operators Assess SDN’s Impact

Key Takeaways on MiniNExT: Enables 1:1 translation of any network into a sandbox environment Helps network operators take a holistic look at how SDN will impact their networks Makes it easier to define network transition plans with confidence

Additional Information on MiniNExT: Talk with me here at the conference

Brandon Schlinker, bschlink@usc.edu

GitHub Repository: MiniNExT