Network Virtualization

Nick Feamster, Georgia TechLixin Gao, UMass AmherstJennifer Rexford, Princeton

NSF NeTS-FIND PI Meeting

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Overview: Three Proposals• Concurrent Architectures are Better than One

– Applications of network virtualization– This talk (Overview): Potential benefits of

virtualization, opportunities and challenges

• Diversified Internet Architecture– Metanetworks, substrate, and applications– Two talks: Technical support for virtualization and

substrate

• Future Optical Internet Architectures– On-the fly creation of point-to-point links– Last talk

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Characteristics

• Virtualization– Multiple logical routers on a single platform– Resource isolation in CPU, memory, bandwidth,

forwarding tables, …

• Programmability– General-purpose CPUs for the control plane– Network processors and FPGAs for data plane– Third-party software for routing and forwarding

Separate the infrastructure from the routing architectures that run on top of it

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Research: Network Embedding

• Given: virtual network and physical network– Topology, constraints, etc.

• Problem: find the appropriate mapping onto available physical resources (nodes and edges)

• Many possible formulations– Specific nodes mapping to certain physical nodes– Generic requirements: “three diverse paths from SF to

LA with 100 MBps throughput”– Traffic awareness, dynamic remapping, etc.– On-the-fly creation of links in the substrate

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Research: Substrate Design• Problem: Brokering of physical infrastructure

– Discovery: Discovering physical infrastructure• Autodiscovery of components and topology• Decision elements that configure components

– Provisioning: Creating virtual networks• Requests to decision elements (initially out of

band), which name virtual network components• Turner et al., Substrate Control Metanet

– Creation: Instantiating virtual networks

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Proposal: Concurrent Architectures are Better than One (“Cabo”)

• Infrastructure: physical infrastructure needed to build networks

• Service: “slices” of physical infrastructure from one or more providers

The same entity may sometimes play these two roles.

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End-to-End Services

• Multi-provider VPNs• Paths with end-to-end performance guarantees

Today Cabo

Competing ISPs with different goals must coordinate

Single service provider controls end-to-end path

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End-to-End Services

Online Banking Web Surfing

Routing Secure routing protocol (e.g., S-BGP)

Lowest common denominator

Addressing Self-certifying addresses(optimized for persistence)

Dynamic addresses(optimized for convenience)

More SecurityMore Complete

Reachability

• Today: Deployment logjam– Deployment requires consensus and coordination

• Instead: Adopt pluralist approach– Determined service provider leases infrastructure and deploys technology end-to-end

Example

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Application-Specific Networks

Internal BGP Link-State Protocols

Dissemination Hierarchical, incremental Flooding

Computation BGP-style decision process Shortest Paths

Better ScalabilityFaster

Convergence

• Today: Optimize a single set of protocols• Instead: Parallel deployment

– Run multiple networks, each catered to specific applications

Example

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Evaluation Platform: VINI

• XORP: control plane• UML: environment

– Virtual interfaces

• Click: data plane– Performance

• Avoid UML overhead• Move to kernel, FPGA

– Interfaces tunnels– “Fail a link”

XORP(routing protocols)

UML

eth1 eth3eth2eth0

Click

PacketForwardEngine

Control

DataUmlSwitch

element

Tunnel table

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First Step: Independence from IP

• Solution: Forwarding should depend on MAC addresses in UML

UML

eth1 eth3eth2eth0

Click

PacketForwardEngine

Control

Data

XORP(routing protocols)

UmlSwitchelement

Tunnel table

Forwarding cannot depend on IP

New Routersand Protocols

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Parallel Deployment: Questions

• Guaranteeing global reachability– Do we need an end-to-end global reachability

service?

• Proliferation of protocols and architectures– Is “low barrier to entry” a good thing for an

architecture?

• Security– Should parallel deployment imply isolation?– If so, how to implement it?

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Economic Refactoring

• Infrastructure providers: maintain physical infrastructure needed to build networks

• Service providers: lease “slices” of physical infrastructure from one or more providers

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Also in Communications Networks

• Packet Fabric: share routers at exchange points• FON: resells users’ wireless Internet connectivity

• Infrastructure providers: Buy upstream connectivity, broker access through wireless

• Nomads: Users who connect to access points• Service provider: FON as broker

Two commercial examples

Broker

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Economic Refactoring: Challenges

• Being a service provider: a great deal– Opportunity to add value by creating new services

• Infrastructure providers– Can this enterprise be profitable?

• Who will become infrastructure providers?

http://www.cc.gatech.edu/~feamster/papers/cabo.pdf

Need to understand whether this refactoring would occur

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Can Other Industries Offer Clues?

• Infrastructure providers: Airports• Infrastructure: Gates, “hands and eyes”, etc.• Service providers: Airlines

SFOATL

BOS

ORD

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Summary

• Network virtualization

• General Challenges– Simultaneous operation– Substrate and interface

• Applications and Opportunities– Parallel deployment– End-to-end services and protocols– Economic refactoring