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Try Before you Buy:
SDN Emulation with (Real) Interdomain Routing
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
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Questions in Legacy Networks:
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Protocol(s) to Use
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Internal Routing (IGPs: OSPF, RIP)
SDN uses centralized controller to make
decisions and focuses on forwarding, not routing
Scalability
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Questions in SDN Networks:
BGP scalability
Controller scalability, switch performance
Equipment Vendor
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Single CLI
Support for vendor-specific technologies
Controller capabilities, interoperability
SDN Creates New Challenges for Operators
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For a Network Operator, SDN =
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New interactions
New components that require redundancy
New scalability and management issues
How Does SDN Impact my Network?
Overwhelmed Network Operator
New Data Centers: Great Environments for Deploying SDN
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Greenfield environment – all new equipment purchased at once
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Homogeneous network -- 100% SDN infrastructure
Built from the ground-up, no risk of downtime during setup
One administrative domain, little interaction with other networks
What about existing ISP and Enterprise Networks?
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ISP Backbone Network
Existing Networks Built Piecemeal Over Multiple Years
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Provider Started at East Coast with One Equipment Vendor
Existing Networks Built Piecemeal Over Multiple Years
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Expanded to West Coast With Different Equipment Vendor
Multiple Technologies Support Large Networks
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Different Technologies Used Across Existing Network
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Different IGPs (OSPF, RIP), Route Reflectors for BGP scalability, Middleboxes
Company acquisitions, sudden growth, vendor specific technologies → heterogeneity
Large Networks Have Interactions with Other Networks
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Multiple Points of Presence for Interacting with Other Networks
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Interactions will continue to use BGP protocol for foreseeable future (even with SDN)
These interactions are important → they define internal traffic patterns
Other Existing Networks Have Similar Problems
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Other Networks May Not Be As Large, But Will Face Similar Problems
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ISPs, Enterprise Networks, Educational Networks, Service Providers
Highly Diverse Network Ecosystem
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Lots of custom configurations, protocols, hidden interactions, outdated decisions
Opposite of environment typically discussed when we talk about SDN
Realities of Transitioning to SDN
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Takes time to migrate existing networks
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Some operators not ready to migrate portions of their network to SDN technologies
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BGP isn’t going away soon (still need to interconnect the Internet)
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Need Hybrid Network for Foreseeable Future
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Need to ensure different technologies in hybrid network play nice
Network Operators….
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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
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Mininet Lacks Support for Emulating Existing Networks…
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Lacks Emulation Support for Key Components in Today’s Networks:
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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
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Impossible to Emulate
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Cannot accurately emulate peer ISPs:
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Unpredictable routes, failures, policies, topologies, business & technical goals
We need more than emulation...
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MiniNExT
Comprehensive Network Emulation of Intra-domain
combined with
Inter-domain Connectivity with Real Networks
MiniNExT’s Extends Mininet’s Emulation Support
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Extends Mininet to Support BGP and IGP Protocols
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Now can support any network type, including hybrid networks
Requires significantly less resources than emulation with virtual machines
MiniNExT Goes Beyond Emulation with Real Connectivity
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BGP Sessions Multiplexed to
Provide Real Connectivity
[Real]
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[Emulated]
Combines Emulated Network with Real BGP Connectivity
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Multiplexes a real network’s existing BGP sessions
Enables emulated and operational network to communicate with peers via BGP
MiniNExT Translates Network 1:1 into Sandbox Environment
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Real Network
MiniNExT
Both
networks can
runTranslation
at the same time
MiniNExT
Sandbox
MiniNExT Combines Emulated Network with Real BGP
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Real BGP Sessions
Emulated with MiniNExT on a laptop
MiniNExT Enables SDN Experiments
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Let’s Change The Data Center Network to SDN
MiniNExT Enables SDN Experiments
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New SDN Data Center (All Other Components The Same)
MiniNExT Emulated Networks Can Exchange Routes, Traffic
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MiniNExT Helps Operators Assess SDN’s Impact
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Key Takeaways on MiniNExT:
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Enables 1:1 translation of any network into a sandbox environment
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Helps network operators take a holistic look at how SDN will impact their networks
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Makes it easier to define network transition plans with confidence
Additional Information on MiniNExT:
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Talk with me here at the conference
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Brandon Schlinker, bschlink@usc.edu
GitHub Repository: MiniNExT