Try Before you Buy: SDN Emulation with (Real) Interdomain Routing 1 Brandon 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 Summit Santa Clara, California, USA March 2014

SDN Presents New Questions for Network Operators 2 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:

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? 3 Overwhelmed Network Operator

New Data Centers: Great Environments for Deploying SDN  Greenfield environment – all new equipment purchased at once  Homogeneous network % SDN infrastructure  Built from the ground-up, no risk of downtime during setup  One administrative domain, little interaction with other networks 4

What about existing ISP and Enterprise Networks? 5 ISP Backbone Network

Existing Networks Built Piecemeal Over Multiple Years 6 Provider Started at East Coast with One Equipment Vendor

Existing Networks Built Piecemeal Over Multiple Years 7 Expanded to West Coast With Different Equipment Vendor

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 8

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 9

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 10

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 11

Network Operators…. 12 How Does an Operator Make Sure SDN Plays Nice In Their Existing Network? What Tools Can These Use To Understand SDN’s Impact?

Mininet Enables Emulation of SDN Networks 13

Mininet Lacks Support for Emulating Existing Networks… 14  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

Emulation Limited Regardless of Emulator 15  Cannot accurately emulate peer ISPs:  Unpredictable routes, failures, policies, topologies, business & technical goals  We need more than emulation... Impossible to Emulate

Mini NExT 16 Comprehensive Network Emulation of Intra-domain combined with Inter-domain Connectivity with Real Networks

Mini NExT ’s Extends Mininet’s Emulation Support 17  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

[Real][Emulated] Mini NExT Goes Beyond Emulation with Real Connectivity 18  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 to Provide Real Connectivity Emulated with MiniNExT

Mini NExT Translates Network 1:1 into Sandbox Environment 19 Real Network Mini NExT Sandbox Both networks can run at the same time Mini NExT Translation

Emulated with Mini NExT on a laptop Mini NExT Combines Emulated Network with Real BGP 20 Real BGP Sessions

Mini NExT Enables SDN Experiments 21 Let’s Change The Data Center Network to SDN

Mini NExT Enables SDN Experiments 22 New SDN Data Center (All Other Components The Same)

Mini NExT Emulated Networks Can Exchange Routes, Traffic 23

Mini NExT Helps Operators Assess SDN’s Impact Key Takeaways on Mini NExT:  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 Mini NExT:  Talk with me here at the conference  Brandon Schlinker,  GitHub Repository: Mini NExT 24