Try Before you Buy:

SDN Emulation with (Real) Interdomain Routing

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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?

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Overwhelmed Network Operator

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? 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

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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…. 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

MiniNExT

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Comprehensive Network Emulation of Intra-domain

combined with

Inter-domain Connectivity with Real Networks

MiniNExT’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]

MiniNExT 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

MiniNExT Translates Network 1:1 into Sandbox Environment 19

Real Network

MiniNExT

Sandbox

Both networks can run at the same time

MiniNExT

Translation

Emulated with MiniNExT on a laptop

MiniNExT Combines Emulated Network with Real BGP 20

Real BGP Sessions

MiniNExT Enables SDN Experiments 21

Let’s Change The Data Center Network to SDN

MiniNExT Enables SDN Experiments 22

New SDN Data Center (All Other Components The Same)

MiniNExT Emulated Networks Can Exchange Routes, Traffic 23

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

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