A WANinLAB for Protocol Development

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A WAN-in-LAB for Protocol Development

• Netlab, Caltech
• Lachlan Andrew, George Lee,
• Steven Low(PI), John Doyle, Harvey Newman

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Outline

• What and why is WAN-in-Lab?
• What can I do with WiL?
• Why would I use WiL?
• How do I use WiL?
• Future plans

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What is WAN-in-Lab?

• Wide Area Network in a laboratory
• Real fibre delays
• Carrier-class routers, switches,

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Why -- Spectrum of tools
cost
abstraction
maths
simulation
emulation
live netwk
WANinLab
All scales are important WAN-in-Lab fills a gap
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What can I do with WAN-in-Lab?
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Other groups interests

• Protocol development
• FAST, delay-based
• MaxNet, explicit signalling
• ADPM, single-bit explicit signalling
• Impact of small buffers (U. Pittsburgh)
• Test automatic configuration of routers
  (MonALISA, Ultralight)
• Test distributed file-system (MojaveFS)

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TCP Benchmarking

• Our current main direction
• Evaluating others protocols, not ours
• Web interface
• Submit kernel patch
• Standard tests automatically performed
• Results mailed back
• Explicit or implicit signalling protocols

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Capabilities Topology

• Four Cisco 7609 OC-48 routers
• Line cards for four physical links
• More virtual links using IP routing
• 18 GbE servers
• Two wired as software routers for AQM
• 2 standalone 10GbE servers
• Library of standard topologies
• Users can also create their own

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Physical topology
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Capabilities Delay

• 24 spools of 100km fibre, many loopbacks
• Set delay by MEMS switching loops in/out
• 130ms physical delay
• more with IP loopback
• 2 Dummynets long delay for cross-traffic

125 ms, 1.8ms steps
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External connections

• Linked to Ultralight, 10Gbps Physics WAN
• Smooth migration testing -gt deployment
• Delay
• longer
• jitter
• Cross traffic
• Monitordata routedthrough WiL

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Why use WAN-in-Lab?
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Why use WiL?

• Complement other levels of abstraction, not
  replace them
• Different ways to use it reasons for each
• Standard platform for TCP benchmarking
• Easier to compare with others results
• No need to write your own test suite

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Artifacts of software delays

• Packets sent on 1ms ticks
• 1Gbps 83,333 pk/s

1ms
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How can I use WAN-in-Lab?
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Management structure
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Time sharing

• Coarse switching between projects
• Servers rebooted, routers reconfigured
• Switchover takes 5 minutes
• Book in advance
• For longer bookings, book further in advance
• Also ad hoc bookings for individual hosts
• Can log in while others have booked

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Future plans
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Future plans

• Benchmarking infrastructure
• Standardise tests
• Use it ourselves
• Develop indices of TCP performance
• Better control over capacities and buffers
• Better cross-traffic generation
• Currently Harpoon
• Investigate differences from DummyNet
• Integrate DAG cards

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Conclusion

• WAN-in-Lab fills the gap between emulation and
  live network experiments
• Seeks to be as realistic as possible
• Long links, simple topology
• Focus will be on TCP benchmarking
• We welcome people to use it
• lthttp//wil.cs.caltech.edugt

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Spare Slides
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Case Study MaxNet
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Aim Wind Tunnel of Networking

• WAN in Lab
• Capacity 2.5 10 Gbps
• Delay 0 120 ms round trip
• Breakable
• Wont take down live network
• Flexible, active debugging
• Passive monitoring, AQM
• Configurable evolvable
• Topology, rate, delays, route
• Modular design stays up to date
• Integral part of RA networks
• Transition from theory, implementation,
  demonstration, deployment
• Transition from lab to marketplace
• Global resource
• Part of global infrastructure UltraLight led by
  Harvey Newman

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Equipment

• 4 Cisco 7609 routers with OC48 line cards
• 6 Cisco ONS 15454 switches
• A few dozen high speed servers
• 1G switch to routers/servers
• Calient switch for OC48
• 2,400 kilometres of fibre, optical amplifiers,
  dispersion compensation modules
• 63ms aggregate RTT delay, in two hops
• 120ms using IP loopbacks

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Accounts

• Mail wil at cs.caltech.edu
• Sudo access to network commands
• Ifconfig//
• Custom commands to set topologies
• Login to routers if required
• Separate accounts for benchmark only

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Configuration -- Delays

• Want maximum delay from limited fibre
• Signals traverse fibre 16 times
• 4 WDM wavelengths
• 4 OC48 (2.5G) MUXed onto OC192 (10G)
• Lots of transponders
• WDM amplifier joins 100km spools ? 200km

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Configuration delays
-------WDM Wavelength--------
16x200km
Amp
Bidirectional 100km
Bidirectional 100km
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Configuration delays

• Delay varied by adjusting the number of OC48 hops
  traversed
• Calient optical switch selects required hops
• Hop lengths 200km up to 1600km
• Maximise granularity given limited switch ports

Switch
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Projects

• TCP benchmarking
• FAST
• Delay-based congestion control
• MaxNet
• Explicit signalling congestion control
• MojaveFS
• New distributed file system
• University of Pittsburgh
• TCP with small buffers
• University of Melbourne
• Single-bit congestion marking

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WAN-in-Lab testbed

• Dummynet and simulation introduce artifacts
• Also need to test on real equipment
• WAN with real delays, located in a single room
• Connected to an external WAN (Ultralight)
• Open for the community to use for benchmarking

OC-48
OC-48
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WAN-in-Lab capabilities
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Configuration -- delays
-------WDM Wavelength--------
Amp
Bidirectional 100km
Bidirectional 100km
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Using WAN-in-Lab

• Contact me lachlan at caltech . Edu
• Coarse timesharing
• Some users set up experiments while others run
  experiments
• Software setup still being developed
• Your chance to influence our directions to tailor
  it to your needs

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Sample MaxNet results

• Achieves realistic delay at 1Gbit/s

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