Technology and Administrative Coordination Issues

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Technology and Administrative Coordination Issues
Pacific Rim Networking Workshop Guy Almes
ltalmes_at_internet2.edugt
Manoa Valley, Oahu 22 February 2002
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Internet2 Engineering Objectives

• Provide our universities with superlative
  networking
• Performance
• Functionality
• Understanding
• Make superlative networking strategic for
  university research and education

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Technology Issues

• Multicast
• IPv6
• Performance
• Measurement
• Security

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Multicast

• Any Source (Conventional) IPv4 Multicast
• Steve Deering's PhD thesis from Stanford
• Led to MBONE, then native IP multicast
• PIM-Sparse, MBGP, and MSDP
• Technical Implications
• Group g has global significance
• Host s creates and joins g and can both send and
  receive packets
• Other hosts can join g and can both send and
  receive packets
• MSDP needed to discover the source(s) sending to
  g
• Each host receives packets from lt,ggt

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Issue Global deployment

• Careful inclusion of ASM IPv4 Multicast in
  international peering
• Inclusion of multicast issues on local campuses
• Bandwidth must be sufficient for all sources to
  all destinations
• Allocation of group IDs

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Issue Multicast Applications

• Access Grid and DVTS distance education and
  conferencing among sets of collaborators
• Streaming Audio/Video
• Sending files to many destinations, as with
  Digital Fountain

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Issue Scalability and SSM

• Recall implications of ASM
• Global Significance of 'g' value
• Any host can join/send to group g
• SSM being deployed to resolve this
• Host s creates a channel lts,ggt
• Others can subscribe to lts,ggt, but only s sends
• Source discovery now trivial, so MSDP not needed
• g now only has local significance
• Easy to support in wide area, but new IGMP needed
• Applications need to be adapted

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IPv6

• Clarify motivation for IPv6
• End-to-end transparency and global addressability
• Supports application innovation, e.g.,
  peer-to-peer
• Support deployment and engineering expertise on
  networks, especially on campus
• Anticipate need for first-class support
• E.g., 10 Gb/s Abilene upgrade
• E.g., Linux, Windows XP

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Issues Training

• Within Internet2, IPv6 Training Workshops
• About 8-10 workshops this year
• First in Los Angeles, hosted by CENIC, in
  February

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Issue Deployment

• Get some IPv6 on each campus/NRN
• Tunneled IPv6 over IPv4 works well
• Performance and network management are limited,
  however
• Prepare for native peering
• Abilene will be native IPv6 as part of current
  upgrade
• Implications for router selection!
• Explore applications, DNS, operational stability,
  multicast

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Issue Performance

• Tunnels limit performance dramatically
• About 30 Mb/s on Cisco 7200, for example
• Some tunnels will exist for some time
• But, we must remove tunnels in all
  performance-sensitive paths
• Thus, remove tunnels from key wide-area
  connections

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Issue Operations

• IPv6 needs to become a 'normal' protocol
• Robustness of DNS etc.
• Mature network management etc.

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End-to-End PerformanceBandwidth

• In former times, very low bandwidth led to
  (correctly) low expectations
• Now, serious bandwidth exists
• TransPac deployment of two OC-12 representative
• Bandwidth growth will likely continue
• North America to Europe as a challenging example

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End-to-End Performance Latency

• Bandwidth is not the only issue
• Neither the speed of light nor geographical
  distance across the Pacific have improved!
• Thus, round-trip times cause problems
• Sluggish TCP convergence
• Interactive applications more difficult
• Thus, direct physical paths needed
• Hawaii can play a role here

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End-to-End Performance Packet Loss

• TCP Throughput ? MTU / (RTT
  ?PacketLoss)
• This packet loss include that due to
• Congestion
• Other sources
• Thus, we need to remove any source of
  non-congestive packet loss

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End-to-End Performance MTU

• There is almost always an Ethernet link somewhere
  along a wide-area path, hence end-to-end MTU
  seldom more than 1500
• But larger MTUs are supported on wide-area links,
  e.g., 9180 on Abilene
• When performance really matters, work to support
  large end-to-end MTUs

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Threats toEnd to End Performance

• Fiber problems
• dirty fiber
• dim lighting
• 'not quite right' connectors

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Threats toEnd to End Performance

• Fiber problems
• Switches
• horsepower
• full vs half-duplex
• head-of-line blocking

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Threats toEnd to End Performance

• Fiber problems
• Switches
• Inadvertently stingy provisioning
• mostly communication
• happens also in international settings

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Threats toEnd to End Performance

• Fiber problems
• Switches
• Inadvertently stingy provisioning
• Wrong Routing
• asymmetric
• best use of Internet2
• distance

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Threats toEnd to End Performance

• Fiber problems
• Switches
• Inadvertently stingy provisioning
• Wrong Routing
• Host issues
• NIC
• OS / TCP stack
• CPU

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Perverse Result

• 'Users' think the network is congested or that
  the Internet2 infrastructure cannot help them
• 'Planners' think the network is underutilized, no
  further investment needed, or that users don't
  need high performance networks

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Measurements

• Traffic utilization
• MRTG, etc., need to be more visible
• Performance-related measurements
• iperf, AMP, Surveyor, etc. along key paths
• Passive measurements
• Netflow becoming mature
• OC3MON hardware-based sampling of actual packets
• Router support becoming available

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Security
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Security An unusual Internet2 Emphasis

• Aspects of Security
• Security of the infrastructure
• Security of user host computers
• Security of information and privacy
• In the post-11-Sep environment
• Society will be less tolerant of lax standards
• Not a distinctly 'Internet2' concern
• but one that all our universities share

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