inter-domain routing, ipv6, and network visualization

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inter-domain routing, ipv6, and network
visualization

• giuseppe di battista
• maurizio patrignani

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main research topics

• interdomain routing
• analysis of the route changes for the incoming
  traffic flows
• location of the internet routing instabilities
• modeling of bgp configurations and analysis of
  their stability
• inference of the customer-provider relationships
• study of the routing (a)symmetries
• engineering of the incoming traffic flows
• discovery of a large(r) as graph
• integration and visualization of the irr info
• intradomain routing
• ospf visualization
• layer-3 discovery techniques
• ipv6
• support for the ipv4-ipv6 transition
• multi-homing methods
• network emulation
• cheap and easy-to-configure test-beds for complex
  networks

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analysis of the route changes for the incoming
traffic flows

• development of a web service, called bgplay,
  visualizing the route changes of a prefix in a
  specific time window
• two running servers at
• routing information service of the ripe ncc
  (www.ris.ripe.net/bgplay/)
• route views project of the oregon university
  (www.routeviews.org)
• each based on the corresponding repository of bgp
  updates
• an alpha version at roma III university with the
  most recent features

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bgplay query form
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(No Transcript)
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bgplay demo
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location of the internet routing instabilities

• monitoring of the network from several vantage
  points
• each vantage point stores the bgp updates that
  are visible from its location
• related updates are grouped into events
• the causes of each event are (if possible)
  identified by studying the evolution of the
  routing over time

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modeling of bgp configurations and analysis of
their stability

• study of formal models for the description of bgp
  configurations and behaviors
• study of the effect of different time sequences
  of the events
• identification of possible routing instabilities
• routing stability vs forwarding stability
• stability of the entire routing information base
  vs stability of the best choice

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inference of the customer-provider relationships

• a simple model accounting for customer-provider
  and peer-to-peer relationships only
• infer the types of relationship between
  autonomous systems by observing the as-paths
  associated with announcements
• if sensible rules of thumb are followed by
  network operators, each as-path is valley free
• if rules of thumb are followed by network
  operators, relationships can be efficiently
  inferred

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inference of the customer-provider relationships

• if a set of relationships making all as-paths
  valley free does not exist
• we prove that maximizing the number of valley
  free as-paths is a hard problem
• we propose heuristics for this problem that
  outperform cutting-edge techniques described in
  literature

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study of the routing (a)symmetries

• netviewer web service
• prototype at www.dia.uniroma3.it/compunet/
• having at disposal internal and external info
  shows routing asymmetries
• group prefixes into classes that have the same
  routing
• in cooperation with caspur and garr

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example of routing classes
198.150.84.0 198.150.85.0 198.150.87.0
198.150.2.0 198.150.22.0 198.150.38.0
198.150.4.0 198.150.5.0 198.150.6.0
198.150.7.0 198.150.9.0
1st July 2003
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example of asymmetric routing
1st July 2003
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engineering of the incoming traffic flows

• even a limited control of the announcements
  propagation could be used to
• balance traffic from the upstream providers
• prefer reliable incoming paths
• improve internal traffic flows
• engineering incoming traffic via prepending
• Integer Linear Programming formulation
• computational geometry perspective

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discovery of a large(r) AS graph

• starting from the bgp updates collected by the
  ris or orv repositories a big picture of the
  internet can be obtained
• this picture can be enlarged by observing
  unusual bgp traffic
• bgp updates with peculiar timings
• bgp updates with peculiar content
• we can gain extra info by
• observing unusual bgp updates
• probing the network with unusual bgp updates
• for example setting up suitable beacons and
  observing echoes
• in cooperation with namex

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integration and visualization of the irr info

• hermes service
• available at www.dia.uniroma3.it/hermes/
• handles a local relational database of routing
  information
• downloads rpsl information from more than 50
  databases that are individually operated by
  organizations such as verio, cable wireless,
  merit, ripe ncc, apnic, arin, sprint, etc.
• through a java applet it is possible to navigate
  the repository and obtain information about the
  rpsl objects

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integration and visualization of the irr info
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integration and visualization of the irr info
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integration and visualization of the irr info
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integration and visualization of the irr info
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integration and visualization of the irr info
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integration and visualization of the irr info
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ospf visualization

• polyphemous tool
• downloadable from www.dia.uniroma3.it/polyph/
• collects routing information using snmp and mibs
• explores an ospf network at different levels of
  abstraction
• shows ospf areas an area border routers
• shows routers and links inside each area
• provides detailed info about areas, routers,
  interfaces.
• in cooperation with caspur

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ospf visualization
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layer-3 discovery techniques

• nethunter service
• available at www.dia.uniroma3.it/nethunt/
• exploits a collection of traceroute servers
• explores the surroundings of an ip interface or
  network by performing traceroutes from different
  vantage points
• uses a logic engine for inferring topologies
• guess and check approach to asses whether two
  interfaces belong to the same router

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support for the ipv4-ipv6 transition

• techniques to detect, and collect information
  about, ipv6-in-ipv4 tunnels (mtu-discovery, dns,
  ip spoofing,)
• discovered tunnels can be used as vantage
  points to launch third-party tunnel-discovery
  explorations, scaling up the discovery process
• wide experimentation
• 6bone tunneled network, garr network, wide
  network, ripe ncc network and ttm test-boxes
• we assess to what extent 6bone registry
  information is coherent with the actual network
  topology
• we provide the first experimental results on the
  current distribution of ipv6-in-ipv4 tunnels in
  the Internet
• in cooperation with garr and ripe ncc

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multi-homing methods

• hosts in a multi-homed as receive an ipv6 address
  from each upstream provider
• how to handle multiple ipv6 addresses?
• need to take into account traffic loads
• need to propagate information from the border
  routers to the internal networks
• need to swap ipv6 addresses without dropping tcp
  connections

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cheap and easy-to-configure test-beds for complex
networks

• netkit (network emulator)
• available at www.netkit.org
• a linux kernel may run as a user process (user
  mode linux)
• a network of linux virtual machines may run on a
  single host
• each linux may be configured to run routing
  daemons (zebra, bird, gated, routed, xorp,
  quagga,)
• new configurations may be tested before being
  deployed
• in cooperation with garr

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concluding remarks

• a mixed theoretical-technical approach in all
  topics
• tight relationships with network operators
• caspur, garr, namex, orv, ripe,
• research-teaching coupling
• univ. courses on comp. networks and courses on
  specific technologies for companies and pa

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thank you!
questions?