Transcript geni-cisco-nag-may06 - cs.Princeton

Next-Generation Network Research Facilities
Jennifer Rexford
Princeton University
http://www.cs.princeton.edu/~jrex
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Outline
• Networking research challenges
– Security, economic incentives, management, layer-2 technologies
• Importance of building and deploying
– Bridging the gap between simulation/testbeds and real deployment
• Global Environment for Network Innovations (GENI)
– Major NSF initiative to support experimental networking research
– Key ideas: virtualization, programmability, and user opt-in
• GENI backbone design
– Programmable routers, flexible optics, and connection to Internet
– Example experiments highlighting the capabilities
• Virtual Network Infrastructure (VINI)
– Initial experimental network facility in NLR and Abilene
• Conclusions
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Is the Internet broken?
• It is great at what it does.
– Everyone should be proud of this.
– All sorts of things can be built on top of it.
• But…
– Security is weak and not getting better.
– Availability continues to be a challenge.
– It is hard to manage and getting harder.
– It does not handle mobility well.
– A long list, once you start…
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Challenges Facing the Internet
• Security and robustness
– Naming and identity
– Availability
• Economic incentives
– Difficulty of providing end-to-end services
– Commoditization of the Internet infrastructure
• Network management
– No framework in the original Internet design
– Tuning, troubleshooting, accountability, …
• Interacting with underlying network technologies
– Advanced optics: dynamic capacity allocation
– Wireless: mobility, dynamic impairments
– Sensors: small embedded devices at large scale
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FIND: Future Internet Design
• NSF research initiative
– Requirements for global network of 10-15 years out?
– Re-conceive the network, if we could design from scratch?
• Conceive the future, by letting go of the present:
– This is not change for the sake of change
– Rather, it is a chance to free our minds
– Figuring out where to go, and then how to get there
• Perhaps a header format is not the defining piece of
a new architecture
– Definition and placement of functionality
– Not just data plane, but also control and management
– And division between end hosts and the network
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The Importance of Building
• Systems-oriented computer science research
needs to build and try out its ideas to be effective
– Paper designs are just idle speculation
– Simulation is only occasionally a substitute
• We need:
– Real implementation
– Real experience
– Real network conditions
– Real users
– To live in the future
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Need for Experimental Facility
Goal: Seamless conception-to-deployment process
Deployment
Analysis
(models)
Simulation / Emulation
(code)
Experiment At Scale
(results)
(measurements)
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Existing Tools
• Simulators
– ns
• Emulators
– Emulab
– WAIL
• Wireless testbeds
– ORBIT
– Emulab
• Wide-area testbeds
–
–
–
–
PlanetLab
RON
X-bone
DETER
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Today’s Tools Have Limitations
• Simulation based on simple models
– Topologies, administrative policies, workloads, failures…
• Emulation (and “in lab” tests) are similarly limited
– Only as good as the models
• Traditional testbeds are targeted
– Not cost-effective to test every good idea
– Often of limited reach
– Often with limited programmability
• Testbed dilemma
– Production network: real users, but hard to make changes
– Research testbed: easy to make changes, but no users
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Bridging the Chasm
Maturity
Global
Experimental
Facility
Deployed
Future
Internet
This chasm is a major
barrier to realizing the
future designs
Small Scale Testbeds
Simulation and Research Prototypes
Foundational Research
Time
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Goals for the Experimental Facility
• Broader impact
– Positive influence on the design of the future Internet
– Network that is more secure, reliable, efficient, manageable, usable
• Intellectual progress
– Network science
• Experimentally answer questions about complex systems
• Better understanding of dynamics, stability, evolvability, etc.
– Network architecture
• Evaluate and compare alternative architectural structures
• Reconcile the contradictory goals an architecture must meet
– Network engineering
• Evaluate engineering trade-offs in a controlled, realistic setting
• Test theories of how different elements might be designed
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GENI
• Experimental facility
– MREFC proposal to build a large-scale facility
– Jointly from NSF’s CS directorate, & research community
– We are currently at the “Conceptual Design” stage
– Will eventually require Congressional approval
• Global Environment for Network Innovations
– Prototyping new architectures
– Realistic evaluation
– Controlled evaluation
– Shared facility
– Connecting to real users
– Enabling new services
See http://www.geni.net
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Three Key Ideas in GENI
• Virtualization
– Multiple architectures on a shared facility
– Amortizes the cost of building the facility
– Enables long-running experiments and services
• Programmable
– Enable prototyping and evaluation of new architectures
– Enable a revisiting of today’s “layers”
• Opt-in on a per-user / per-application basis
– Attract real users
• Demand drives deployment / adoption
– Connect to the Internet
• To reach users, and to connect to existing services
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Slices
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Slices
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User Opt-in
Client
Proxy
Server
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Realizing the Ideas
• Slices embedded in a substrate of resources
– Physical network substrate
• Expandable collection of building block components
• Nodes / links / subnets
– Software management framework
• Knits building blocks together into a coherent facility
• Embeds slices in the physical substrate
• Builds on ideas in past systems
– PlanetLab, Emulab, ORBIT, X-Bone, …
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National Fiber Facility
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+ Programmable Routers
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+ Clusters at Edge Sites
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+ Wireless Subnets
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+ ISP Peers
ISP 2
ISP 1
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Closer Look
Sensor Network
backbone wavelength
Dynamic
Configurable
backbone switch Swith
Customizable
Router
Internet
Wireless Subnet
Edge Site
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GENI Substrate: Summary
• Node components
– Edge devices
– Customizable routers
– Optical switches
• Bandwidth
– National fiber facility
– Tail circuits
• Wireless subnets
–
–
–
–
–
Urban 802.11
Wide-area 3G/WiMax
Cognitive radio
Sensor net
Emulation
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GENI Management Core
Management Services
- name space for users, slices, & components
GMC
- set of interfaces (“plug in” new components)
- support for federation (“plug in” new partners)
Substrate Components
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Hardware Components
Substrate HW
Substrate HW
Substrate HW
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Virtualization Software
Virtualization SW
Virtualization SW
Virtualization SW
Substrate HW
Substrate HW
Substrate HW
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Component Manager
CM
CM
CM
Virtualization SW
Virtualization SW
Virtualization SW
Substrate HW
Substrate HW
Substrate HW
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GENI Management Core (GMC)
Slice Manager
GMC
Resource Controller
slice_spec
(object hierarchy)
Auditing Archive
node
control
sensor
data
CM
CM
CM
Virtualization SW
Virtualization SW
Virtualization SW
Substrate HW
Substrate HW
Substrate HW
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Federation
GMC
GMC
...
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User Front-End(s)
GUI
Front-End
(set of management services)
provisioning service
file & naming service
information plane
GMC
GMC
...
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Virtualization in GENI
• Multiple levels possible
– Different level required by different experiments
– Different level depending on the technology
• Example “base cases”
– Virtual server (socket interface / overlay tunnels)
– Virtual router (virtual line card / static circuits)
– Virtual switch (virtual control interface / dynamic circuits)
– Virtual AP (virtual MAC / fixed spectrum allocation)
• Specialization
– The ability to install software in your own virtual-*
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Distributed Services in GENI
• Goals
– Complete the GENI management story
– Lower the barrier-to-entry for researchers (students)
• Example focus areas
– Provisioning (slice embedder)
– Security
– Information plane
– Resource allocation
– Files and naming
– Topology discovery
– Development tools
– Interfacing with the Internet, and IP
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GENI Security
• Limits placed on a slice’s “reach”
– Restricted to slice and GENI components
– Restricted to GENI sites
– Allowed to compose with other slices
– Allowed to interoperate with legacy Internet
• Limits on resources consumed by slices
– Cycles, bandwidth, disk, memory
– Rate of particular packet types, unique addrs per second
• Mistakes (and abuse) will still happen
– Auditing will be essential
– Network activity
slice
responsible user(s)
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Success Scenarios
• Change the research process
– Sound foundation for future network architectures
– Experimental evaluation, rather than paper designs
• Create new services
– Demonstrate new services at scale
– Attract real users
• Aid the evolution of the Internet
– Demonstrate ideas that ultimately see real deployment
– Provide architectural clarity for evolutionary path
• Lead to a future global network
– Purist: converge on a single new architecture
– Pluralist: virtualization supporting many architectures
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Working Groups to Flesh Out Design
• Research (Dave Clark and Scott Shenker)
– Usage policy / requirements / instrumentation
• Architecture (Larry Peterson and John Wroclawski)
– Define core modules and interfaces
• Backbone (Jen Rexford and Dan Blumenthal)
– Fiber facility / routers & switches / tail circuits / peering
• Wireless (Dipankar Raychaudhuri and Deborah Estrin)
– RF technologies / deployment
• Services (Tom Anderson, Reiter)
– Edge sites / infrastructure and underlay services
• Education
– Training / outreach / course development
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GENI Backbone Requirements
• Programmability
– Flexible routing, forwarding, addressing, circuit set-up, …
• Isolation
– Dedicated bandwidth, circuits, CPU, memory, disk
• Realism
– User traffic, upstream connections, propagation delays, equipment
failure modes, …
• Control
– Inject failures, create circuits, exchange routing messages
• Performance
– High-speed packet forwarding and low delays
• Security
– Preventing attacks on the Internet, and on GENI itself
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A Researcher’s View of GENI Backbone
• Virtual network topology
– Nodes and links in a particular topology
– Resources and capabilities per node/link
– Embedded in the GENI backbone
• Virtual router and virtual switch
– Abstraction of a router and switch per node
– To evaluate new architectures (routing, switching,
addressing, framing, grooming, layering, …)
• GENI backbone capabilities evolve over time
– To realize the abstractions at finer detail
– To scale to a larger number of experiments
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Creating a Virtual Topology
Some links created by
cutting through other nodes
Allocating a fraction
of a link and node
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GENI Backbone
PC Clusters
Wireless
Subnets
ISP 1
Programmable
Routers
ISP 2
Dynamic
ROADMs
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GENI Backbone Node Components
• Phase 0 – General purpose blade server
– Single node with collection of assignable resources
– Virtual Router may be assigned VM, blade or >1 blades
• Phase 1 – Adding higher performance components
– Assignable Network Processor blades and FPGA blades
– NPs also used for I/O for better control of I/O bandwidth
• Phase 2 – Adding reconfigurable cross-connect
– Enable experiments with configurable transport layer
– Provide “true circuits” between backbone virtual routers
• Phase 3 – Adding dynamic optical switch
– Dynamic optical switch with programmable groomer and
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framer, and reconfigurable add/drop multiplexers
...
Pn
P3
P2
– Node with collection of
assignable resources
– Virtual Router may be
assigned a virtual machine,
blade, or multiple blades
P1
• Phase 0 – General
purpose blade server
Mgmt.
Proc.
Mgmt. Proc.
GENI Backbone Node Components
Switch
Switch
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GENI Backbone Node Components
LCk
...
LC1
...
PEn
PE2
– Assignable Network
Processor blades and
FPGA blades
– NPs also used for I/O for
better control of bandwidth
– ATCA chassis and blades
PE1
• Phase 1 – Adding higher
performance components
Mgmt.
Proc.
Mgmt. Proc.
10 GigE Links
Switch
Switch
GP Blade
Server
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GENI Backbone Node Components
• Phase 2 – Reconfigurable
cross-connect
Control Plane
– Enable experiments with
configurable transport layer
– Provide “true circuits”
between backbone virtual
routers
– Cut-through traffic
circumvents the router
Customizable
Router
1 GE
10GE+VLAN
Programmable
Cross-Connect/
Groomer
Wavelength
tunable
transponders
/combiner
WDM Fiber
VR
VR
VX
VR
VR
VX
VR
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GENI Backbone Node Components
– Dynamic optical switch with
programmable groomer and
framer, and reconfigurable
add/drop multiplexers
– Maleable bandwidth
– Arbitrary framing
Customizable
Router
Control Plane
• Phase 3 – Adding dynamic
optical switch
1 GE
10GE+VLAN
Programmable
Cross-Connect/
Groomer
Wavelength
tunable
transponders
ROADM
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GENI Backbone Software
• Component manager and virtualization layer
– Abstraction of virtual router and virtual switch
– Setting scheduling parameters for subdividing resources
• Multiplexers for resources hard to share
– Single BGP session with the outside world
– Single interface to an element-management system
• Exchanging traffic with the outside world
– Routing and forwarding software to evaluate & extend
– VPN servers and NATs at the GENI/Internet boundary
• Libraries to support experimentation
– Specifying, controlling, and measuring experiments
– Auditing and accounting to detect misbehavior
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Feasibility
• Industrial trends and standards
– Advanced Telecom Computing Architecture (ATCA)
– Network processors and FPGAs
– SONET cross connects and ROADMs
• Open-source networking software
– Routing protocols, packet forwarding, network address
translation, diverting traffic to an overlay
• Existing infrastructure
– PlanetLab nodes, software, and experiences
– National Lambda Rail and Abilene backbones
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Example Experiment: End-System Multicast
• End-System Multicast
– On-demand, live streaming of audio/video to many clients
– Intermediate nodes forming a multicast tree
• Ways GENI could support ESM research
– Backbone nodes participating in the multicast tree
– New network architectures running under ESM
• Live: native multicast support and QoS guarantees
• Pre-recorded: burst transfer, push, and network-storage
GENI
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Example Experiment: Routing Control Platform
• Routing Control Platform (RCP)
– Refactoring of control and management planes
– Computes forwarding tables in separate servers
• Ways GENI can support RCP research
– Providing direct control over the data plane
– BGP sessions with the commercial Internet
– Controlled experiments with node/link failures
BGP with ISPs
RCP
BGP with ISPs
GENI
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Example Experiment: Valiant Load Balancing
• Valiant Load Balancing
– Fully mesh of circuits between routers
– Direct traffic through intermediate node
• Ways GENI can support VLB
– Virtual circuits with dedicated bandwidth
– Experimentation with routing
r1
2r1r2/RN
– Measurement of effects of
r2
1
2
higher delay vs. higher
throughput on users
r3
rN N
3
– Explore impact on
buffer sizing in routers
4
…
r4
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Example Experiments: TCP Switching
• TCP switching
– TCP SYN packet triggers circuit set-up
– Effective traffic management and quality of services
• Ways GENI can support TCP flow switching
– Programmable routers act as edge routers
• Trigger circuit set-up and tear-down
• Buffer data packets during circuit set-up
– Measure overheads and performance
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VINI: Step Toward GENI Backbone
• Virtual Network Infrastructure (VINI)
– Multiple network experiments in parallel
– Connections to end users and upstream providers
– Supporting Internet protocols and new designs
• VINI as an initial experimental platform
– Support researchers doing network experiments
– Explore software challenges of building GENI backbone
• GENI will have a much wider scope
– Programmable hardware routers
– Flexible control of the optical components
– Wireless and sensor networks at the edge
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Network Infrastructure
• Network topology
– Points of Presence
– Link bandwidth
– Upstream connectivity
• Two backbones
– Abilene Internet2
– National Lambda Rail
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Building Virtual Networks
• Physical nodes
– Initially, high-end computers
– Later, network processors and FPGAs
• Virtual routers (a la PlanetLab)
– Multiple virtual servers on a single node
– Separate shares of resources (e.g., CPU, bandwidth)
– Extensions for resource guarantees and priority
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Building Virtual Links
• Creating the illusion of interfaces
– Create a tunnel for each link in the topology
– Assign IP addresses to the end-points of tunnels
– Match tunnels with one-hop links in the real topology
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Building Multiple Virtual Topologies
• Separate topology per experiment
– Routers are virtual servers
– Links are a subset of possible tunnels
• Creating a customized environment
– Running User Mode Linux (UML) in a virtual server
– Configuring UML to see multiple interfaces
– Enables running the routing software “as is”
R
R
R
R
R
Operating System
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Overcoming Efficiency Challenges
• Packet forwarding must be fast
– But, we are doing packet forwarding in software
– And don’t want the extra overhead of UML
• Solution: separate packet forwarding
– Routing protocols running within UML
– Packet forwarding running outside of UML
XORP
UML
XORP: routing software
Click: forwarding software
Click
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Carrying Real User Traffic
• Users opt in to VINI
• External Internet hosts
– User runs VPN client
– Connects to VINI node
– VINI connects to Internet
– Apply NAT at boundary
VINI
XORP
UML
Click
routing-protocol
messages
Client
XORP
Open
VPN
UML
Click
XORP
UDP
tunnels
UML
Click
Server
Network
Address
Translation
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Example VINI Experiment
• Configure VINI just like Abilene
– VINI node per PoP
– VINI link per inter-PoP link
– Routing configuration as real routers
• Network event
– Inject link failure between two PoPs
– … in midst of an ongoing file transfer
• Measuring routing convergence
– Packet monitoring of the data transfer
– Active probes of round-trip time & loss
– Detailed view of effects on data traffic
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VINI Current Status
• Initial Abilene deployment
– Eleven sites
– Nodes running XORP and Click on UML
• Upcoming deployment
– Six sites in National Lambda Rail
– … with direct BGP sessions with CRS-1 routers
– Dedicated 1 Gbps bandwidth between Abilene sites
• In the works
– Upstream connectivity via a commercial ISP in NYC
– Speaking interdomain routing with the Internet
Initial write-up: http://www.cs.princeton.edu/~jrex/papers/vini.pdf
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Conclusions
• Future Internet poses many research challenges
– Security, network management, economics, layer-2, …
• Research community should rise to the challenge
– Conceive of future network architectures
– Prototype and evaluate architectures in realistic settings
• Global Environment for Network Innovations (GENI)
– Facility for evaluating new network architectures
– Virtualization, programmability, and user opt-in
• GENI backbone design
– Fiber facility, tail circuits, and upstream connectivity
– Programmable router and dynamical optical switch
• VINI prototype
– Concrete step along the way to the GENI backbone
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