inter-domain routing, ipv6, and network visualization

1. computer networks research group @ roma III university inter-domain routing, ipv6, and network visualization giuseppe di battista maurizio patrignani

2. 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 computer networks research group @ roma III university - namex 19 nov 04

3. 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 computer networks research group @ roma III university - namex 19 nov 04

4. specify the prefix (network) you want to monitor specify an interval of time select data sources bgplay query form computer networks research group @ roma III university - namex 19 nov 04

5. computer networks research group @ roma III university - namex 19 nov 04

6. bgplay demo computer networks research group @ roma III university - namex 19 nov 04

7. 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 computer networks research group @ roma III university - namex 19 nov 04

8. 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 computer networks research group @ roma III university - namex 19 nov 04

9. 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 computer networks research group @ roma III university - namex 19 nov 04

10. 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 computer networks research group @ roma III university - namex 19 nov 04

11. 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 computer networks research group @ roma III university - namex 19 nov 04

12. 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 computer networks research group @ roma III university - namex 19 nov 04

13. = 129.125.0.0/16 = 130.136.0.0/16 example of asymmetric routing 1st July 2003 computer networks research group @ roma III university - namex 19 nov 04

14. 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 computer networks research group @ roma III university - namex 19 nov 04

15. 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 computer networks research group @ roma III university - namex 19 nov 04

16. 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 computer networks research group @ roma III university - namex 19 nov 04

17. integration and visualization of the irr info computer networks research group @ roma III university - namex 19 nov 04

18. integration and visualization of the irr info computer networks research group @ roma III university - namex 19 nov 04

19. integration and visualization of the irr info computer networks research group @ roma III university - namex 19 nov 04

20. integration and visualization of the irr info computer networks research group @ roma III university - namex 19 nov 04

21. integration and visualization of the irr info computer networks research group @ roma III university - namex 19 nov 04

22. integration and visualization of the irr info computer networks research group @ roma III university - namex 19 nov 04

23. 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 computer networks research group @ roma III university - namex 19 nov 04

24. ospf visualization computer networks research group @ roma III university - namex 19 nov 04

25. 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 computer networks research group @ roma III university - namex 19 nov 04

26. 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 computer networks research group @ roma III university - namex 19 nov 04

27. 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 computer networks research group @ roma III university - namex 19 nov 04

28. 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 computer networks research group @ roma III university - namex 19 nov 04

29. 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 computer networks research group @ roma III university - namex 19 nov 04

30. thank you! questions? computer networks research group @ roma III university - namex 19 nov 04