VINI:%20Virtual%20Network%20Infrastructure

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VINI Virtual Network Infrastructure

• Jennifer Rexford
• Princeton University
• http//www.cs.princeton.edu/jrex

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The Internet A Remarkable Story

• Tremendous success
• From research experiment to global communications
  infrastructure
• The brilliance of under-specifying
• Best-effort packet delivery service
• Key functionality at programmable end hosts
• Enabled massive growth and innovation
• Ease of adding hosts and link technologies
• Ease of adding services (Web, P2P, VoIP, )
• But, change is easy only at the edge ?

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Internet is Showing Signs of Age

• Security
• Weak notions of identity that are easy to spoof
• Protocols that rely on good behavior
• Mobility
• Hierarchical addressing closely tied with routing
• Presumption that communicating hosts are
  connected
• Availability
• Poor visibility into underlying shared risks
• Multiple interconnected protocols and systems
• Network management
• Many coupled, decentralized control loops

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Variety of Architectural Solutions

• Revisiting definition placement of function
• Naming, addressing, and location
• Routing, forwarding, and addressing
• Management, control, and data planes
• End hosts, routers, and operators
• Designing with new constraints in mind
• Selfish and adversarial participants
• Mobile hosts and disconnected operation
• Large number of small, low-power devices
• Ease of network management

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Hurdle 1 Deployment Dilemma

• An unfortunate catch-22
• Must deploy an idea to demonstrate feasibility
• Cant get an undemonstrated idea deployed
• A corollary the testbed dilemma
• Production network real users, but cant change
• Research testbed easy changes, but no users
• Bad for the research community
• Good ideas sit on the shelf
• Promising ideas do not grow up into good ones

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Hurdle 2 Too Many Design Goals

• Many different system-engineering goals
• Scalability, reliability, security, privacy,
  robustness, performance guarantees,
• Perhaps we cannot satisfy all of them at once
• Applications have different priorities
• Online banking security
• Web surfing privacy, high throughput
• Voice and gaming low delay and loss
• Compromise solution isnt good for anyone

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Hurdle 3 Coordination Constraint

• Difficult to deploy end-to-end services
• Benefits only when most networks deploy
• No single network wants to deploy first
• Many deployment failures
• QoS, IP multicast, secure routing, IPv6,
• Despite solving real, pressing problems
• Increasing commoditization of ISPs

1
2
3
sender
receiver
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Virtualization to the Rescue

• Multiple customized architectures in parallel
• Multiple logical routers on a single platform
• Isolation of resources, like CPU and bandwidth
• Programmability for customizing each slice

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Overcoming the Hurdles

• Deployment Dilemma
• Run multiple experimental networks in parallel
• Some are mature, offering services to users
• Isolated from others that are works in progress
• Too Many Design Goals
• Run multiple operational networks in parallel
• Customized to certain applications and users
• Coordination Constraint
• Run multiple end-to-end services in parallel
• Over equipment owned by different parties

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Three Projects GENI, VINI, CABO

• Global Environment for Network Innovations
• Large initiative for a shared experimental
  facility
• Jointly between NSF CISE division community
• Distributed systems, wireless, optics, backbone
• VIrtual Network Infrastructure
• Baby step toward the design of GENI
• Systems research on network virtualization
• Concurrent Architectures Better than One
• Clean-slate architecture based on virtualization
• Economic refactoring for end-to-end services

See http//www.geni.net and http//www.vini-verita
s.net
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VINI Offers Controlled Realism

• Start with a controlled experiment
• Relax constraints, study effects
• Result an operational virtual network thats
• Feasible
• Valuable
• Robust
• Scalable, etc.

Real clients, servers
Synthetic or traces
Traffic
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Fixed Infrastructure
Deployed VINI nodes in National Lambda Rail and
Abilene, and PoPs in Seattle and Virginia
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Shared Infrastructure
Experiments given illusion of dedicated hardware
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Flexible Topology
VINI supports arbitrary virtual topologies
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Network Events
VINI exposes, can inject network failures
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External Connectivity
s
Experiments can carry traffic for real end-users
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External Routing Adjacencies
s
Experiments can participate in Internet routing
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Virtualizing the Computer

• Starting with the PlanetLab software
• Simultaneous experiments in separate VMs
• Each has root in its own VM, can customize
• Reserve processing resources per VM

Node Mgr
Local Admin
VM1
VM2
VMn

Virtual Machine Monitor (VMM) (Linux)
PlanetLab node
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Creating the Virtual Topology

• Goal real routing protocols on virtual network
  topologies
• Various routing protocols (BGP, OSPF, RIP, IP
  multicast)
• Run unmodified routing software in a PlanetLab VM

XORP (routing protocols)
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User-Mode Linux Environment
UML

• Interface network
• PlanetLab limitation
• Does not virtualize the underlying network
• Level of indirection
• Run routing software in UML environment
• Create virtual network interfaces in UML

XORP (routing protocols)
eth1
eth3
eth2
eth0
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Click Data Plane

• Interfaces ? tunnels
• Click UDP tunnels correspond to UML network
  interfaces
• Filters
• Fail a link by blocking packets at tunnel
• Forwarding packets
• Avoid UML overhead
• Around 200 Mbps
• Not good enough

UML
XORP (routing protocols)
eth1
eth3
eth2
eth0
Control
Data

Packet Forward Engine
UmlSwitch element
Tunnel table
Click
Filters
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Operating System Extensions

• Move data plane into the operating system
• Higher speed, lower jitter, and better
  scalability
• Virtualize the network data structures
• Separate forwarding table per virtual host
• Virtual links inside the operating system
• Terminate tunnels inside the operating system
• No data copying leads to fast packet forwarding
• Resource isolation
• Apply traffic shaping to control resource usage

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Three-Level Design

• Virtual host, in user space
• Experimenters software
• Routing protocols, applications
• Virtual host, in the OS
• Forwarding tables
• Virtual Ethernet interfaces
• Shared substrate, in the OS
• Tunnels between VINI nodes
• Shaping to enforce rate limits

Research experiment
Forwarding table, Virtual interfaces
Traffic shaping, Tunnel interfaces
Network
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Intra-domain Route Changes
s
2095
856
700
260
233
1295
c
639
548
366
846
587
902
1893
1176
Watch OSPF route convergence on Abilene
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Ping During Link Failure
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TCP Throughput
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Arriving TCP Packets
VINI enables a virtual network to behave like a
real network
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Other Example VINI Experiments

• Scaling Ethernet to a large enterprise
• Routing-protocol support for mobile hosts
• Network-layer support for overlay services
• Piggybacking diagnostic data on packets
• ltInsert your prototype system heregt
• Multiple solutions to multiple problems

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Theoretical Challenges

• In collaboration with Mung Chiang

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1. VINI Management Framework

• Managing individual nodes
• Instantiates virtual nodes and virtual links
• Configures the CPU and link schedulers
• Monitors the behavior of the virtual nodes
• Instantiating virtual networks
• Admission control
• Book-keeping of node and link resources
• Topology embedding
• Finding available node and link resources

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Theory Angle Network Embedding

• Virtual network embedding problem
• Given a set of virtual network topologies
• With node and link constraints
• Assign physical nodes and paths

Virtual network
VINI substrate
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Theory Angle Network Embedding

• Computationally intractable problem
• Online problem, with node and link constraints
• Two possible approaches
• Could work on effective heuristics
• Or, change the problem to make it easier!
• Modifying the substrate to simply embedding
• Splitting virtual link over multiple substrate
  paths
• Migration of virtual links and virtual nodes
• With Mung Chiang, Yung Yi, and Minlan Yu

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2. Virtualization as a Deployment Platform

• Moving beyond experimental facilities
• Helping providers run their networks better
• Customized virtual networks
• Security for online banking
• Fast-convergence for VoIP and gaming
• Anonymity and throughput for Web traffic
• Testing and deploying new protocols
• Evaluate on a separate virtual network
• Rather than in a dedicated test lab
• Large scale and early-adopter traffic

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Theory Angle Virtualization

• Theoretical foundation for virtualization
• Does running customized protocols in parallel
  make sense?
• Or, does it waste resources, or add complexity?
• Example supporting two classes of traffic
• Two applications with different utility functions
• E.g., delay-sensitive vs. throughput-sensitive
• Where should the traffic go (routing)?
• What source rates to use (congestion control)?
• One architecture or two?

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Theory Angles Virtualization

• Layering as optimization decomposition
• Formulate the joint optimization problem
• Primal decomposition to generate the protocols

Master problem
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Theory Angles Virtualization

• Primal decomposition Virtualization
• Separable objectives for the two classes
• Solve each subproblem independently
• Dynamically adapt the share of resources
• Virtualization may indeed make sense
• Design and run each protocol independently on its
  own virtual network
• With cooperation between virtual networks to
  adapt the resource shares
• Ongoing work with Mung Chiang, Jiayue He, and Rui
  Zhang-Shen

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2. Virtualization for Economic Refactoring
Infrastructure Providers
Service Providers

• Infrastructure providers Maintain routers,
  links, data centers, and other physical
  infrastructure
• Service providers Offer end-to-end services
  (e.g., layer 3 VPNs, SLAs, etc.) to users

Today ISPs try to play both roles, and cannot
offer end-to-end services
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Similar Trends in Other Industries

• Commercial aviation
• Infrastructure providers Airports
• Infrastructure Gates, hands and eyes support
• Service providers Airlines

JFK
SFO
NRT
ATL
E.g. airplanes, auto industry, and commercial
real estate
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Communications Networks, Too!

• Two commercial examples in IP networks
• Packet Fabric share routers at exchange points
• FON resells users wireless Internet connectivity

• FON economic refactoring
• Infrastructure providers Buy upstream
  connectivity
• Service provider FON as the broker (www.fon.com)

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3. Theory Angles Many Questions

• Virtual network embedding
• With multiple infrastructure providers
• Auctions for virtual nodes and links?
• Cooperation to create virtual links?
• Modeling of the economic landscape
• Analogies to other fields can be dangerous
• Does the economic factoring really make sense?
• Appropriate incentives for service providers and
  infrastructure providers alike

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Conclusion

• The Internet needs to change
• Security, mobility, availability, management,
• We can overcome barriers to change
• Enable realistic experimentation with new ideas
• Enable multiple designs with different trade-offs
• Enable end-to-end deployment of new services
• Network virtualization is the key
• Run many research experiments in parallel
• Offer customized end-to-end services in parallel
• VINI as an enabling experimental platform