Structure of the Internet Fred Baker

Campus Networks (LANs) Today’s Internet Campus Networks (LANs) The optical internet backbone Gigabit to terabit links UoSAT-12 Internet in Airlines Access networks xDSL, cable modem, ISDN, asynchronous dial 20,000 instantaneous sessions per GBPS backbone bandwidth

Nearby Traceroute traceroute to www.LB-A.stanford.edu (171.64.14.238), 30 hops max, 40 byte packets  1  sjcm-dc-gw1.cisco.com (171.69.25.2)  0.86 ms  0.49 ms  0.54 ms  2  sjce-sbb1-gw1.cisco.com (171.69.14.113)  0.54 ms  0.48 ms  0.35 ms  3  sjck-rbb-gw2.cisco.com (171.69.14.45)  0.39 ms  0.39 ms  0.48 ms  4  sj-wall-1.cisco.com (171.69.7.182)  0.59 ms  0.35 ms  0.51 ms  5  sjce-dirty-gw1.cisco.com (128.107.240.197)  2.01 ms  0.74 ms  0.66 ms  6  barrnet-gw.cisco.com (128.107.239.54)  1.88 ms  0.67 ms  0.60 ms  7  p3-3.paloalto-cr2.bbnplanet.net (4.0.26.13)  3.13 ms  1.74 ms  1.48 ms  8  p1-0-0.paloalto-cr9.bbnplanet.net (4.0.2.214)  2.94 ms  1.73 ms  2.94 ms  9  f0-0.paloalto-cr13.bbnplanet.net (131.119.4.22)  5.07 ms  2.22 ms  1.86 ms 10  sunet-gateway.stanford.edu (198.31.10.1)  7.36 ms  4.42 ms  1.81 ms

Nearby Traceroute traceroute to arachne.berkeley.edu (169.229.131.109), 30 hops max, 40 byte packets  1  sjcm-dc-gw1.cisco.com (171.69.25.2)  0.85 ms  0.57 ms  0.60 ms  2  sjce-sbb1-gw1.cisco.com (171.69.14.113)  0.50 ms  0.38 ms  0.40 ms  3  sjce-rbb-gw1.cisco.com (171.69.14.33)  0.56 ms  0.42 ms  0.44 ms  4  sj-wall-1.cisco.com (171.69.7.170)  0.46 ms  0.47 ms  0.37 ms  5  sjce-dirty-gw1.cisco.com (128.107.240.197)  0.69 ms  0.86 ms  1.11 ms  6  barrnet-gw.cisco.com (128.107.239.54)  0.63 ms  2.33 ms  0.60 ms  7  p3-3.paloalto-cr2.bbnplanet.net (4.0.26.13)  2.04 ms  1.39 ms  1.36 ms  8  p7-1.paloalto-nbr2.bbnplanet.net (4.0.6.77)  1.53 ms  1.53 ms  1.43 ms  9  p1-0.paix-bi1.bbnplanet.net (4.0.6.102)  1.76 ms  1.84 ms  2.19 ms 10  p0-0.xpaix21-qwest.bbnplanet.net (4.2.49.14)  1.94 ms  1.77 ms  1.83 ms 11  205.171.205.29 (205.171.205.29)  3.24 ms  3.80 ms  3.50 ms 12  205.171.14.98 (205.171.14.98)  3.91 ms  3.34 ms  2.70 ms 13  65.113.32.210 (65.113.32.210)  4.14 ms  2.61 ms  3.02 ms 14  QSV-M10-C2.GE.calren2.net (137.164.12.166)  4.40 ms  2.76 ms  2.55 ms 15  atm1-1-0dot1.inr-new-666-doecev.Berkeley.EDU (128.32.0.69)  7.08 ms  6.25 ms  5.70 ms 16  vlan196.inr-202-doecev.Berkeley.EDU (128.32.0.75)  9.39 ms  10.38 ms  8.58 ms 17  vlan210.inr-203-eva.Berkeley.EDU (128.32.255.10)  11.67 ms  13.90 ms  13.32 ms 18  arachne.Berkeley.EDU (169.229.131.109)  12.27 ms  8.01 ms  8.05 ms

International Traceroute traceroute to bells.cs.ucl.ac.uk (128.16.5.31), 30 hops max, 40 byte packets  1  sjcm-dc-gw1.cisco.com (171.69.25.2)  0.83 ms  0.67 ms  0.85 ms  2  sjce-sbb1-gw1.cisco.com (171.69.14.113)  0.47 ms  1.43 ms  0.41 ms  3  sjce-rbb-gw1.cisco.com (171.69.14.33)  0.44 ms  0.37 ms  0.34 ms  4  sj-wall-1.cisco.com (171.69.7.170)  0.39 ms  0.37 ms  0.35 ms  5  sjce-dirty-gw1.cisco.com (128.107.240.197)  1.65 ms  0.68 ms  0.61 ms  6  sjc-k-isp-gw1.cisco.com (128.107.239.90)  1.94 ms  1.53 ms  0.62 ms  7  POS2-3.GW5.SJC2.ALTER.NET (65.208.80.241)  2.28 ms  3.43 ms  2.35 ms  8  161.ATM5-0.XR2.SJC2.ALTER.NET (146.188.144.54)  2.62 ms  1.41 ms  1.22 ms  9  0.so-1-0-0.XL2.SJC2.ALTER.NET (152.63.56.141)  3.11 ms  2.27 ms  1.57 ms 10  0.so-3-0-0.TL2.SAC1.ALTER.NET (152.63.54.10)  5.77 ms  4.80 ms  4.77 ms 11  0.so-7-0-0.IL2.NYC9.ALTER.NET (152.63.9.185)  71.02 ms  69.89 ms  69.77 ms 12  so-1-0-0.IR2.NYC12.ALTER.NET (152.63.23.70)  71.09 ms  69.91 ms  70.65 ms 13  so-5-0-0.TR1.LND9.Alter.Net (146.188.15.49)  142.83 ms  141.74 ms  141.50 ms 14  so-5-0-0.XR2.LND9.Alter.Net (146.188.15.38)  146.52 ms  144.97 ms  145.10 ms 15  pos2-0.gw1.lnd9.alter.net (158.43.150.146)  142.46 ms  141.63 ms  142.83 ms 16  ukerna-gw.pipex.net (158.43.37.202)  142.69 ms  141.64 ms  141.42 ms 17  po15-0.lond-scr.ja.net (146.97.35.137)  142.95 ms  141.62 ms  141.63 ms 18  po0-0.london-bar1.ja.net (146.97.35.2)  142.86 ms  141.86 ms  141.74 ms 19  146.97.40.34 (146.97.40.34)  142.89 ms  141.81 ms  141.81 ms 20  ucl.lmn.net.uk (194.83.101.6)  146.57 ms  145.71 ms  145.40 ms 21  128.40.20.61 (128.40.20.61)  143.63 ms  142.67 ms  143.36 ms 22  128.40.20.14 (128.40.20.14)  147.24 ms  145.81 ms  145.76 ms 23  cisco.cs.ucl.ac.uk (128.40.14.1)  147.48 ms  145.97 ms  145.84 ms 24  bells.cs.ucl.ac.uk (128.16.5.31)  172.75 ms  142.54 ms  146.16 ms

Autonomous System Interconnection Access Networks AS: “A routing system using a single protocol and under common administration” AS in center High connectivity AS at edge Low connectivity Major ISPs

Routing by contract BGP Routing is essentially routing by contract Goal is not to achieve a good route, but a usable one for which money changes hands Broad contract categories: “Peering” “Transit”

Peering Contracts Contract among equals “I will advertise my customers to you” To get full routes, have to peer with every major network Relatively expensive to service Packets that enter my network will always be delivered in my network Peering contracts may produce little or no revenue, as they are essentially a trade for access to peer’s customers

Transit contracts Contract between provider and customer “I will advertise the ability to get anywhere” Often some combination of default and individual routes “Full” routes can be gotten from any major provider, but may be inefficient routes. Relatively inexpensive to service Packets often handed to next hop network quickly, Packets only sometimes spend time in my network However, transit contracts produce revenue

Components of agreements Contracts always under NDA Therefore little direct knowledge outside key players Key components Routes advertised Ability to advertise routes Assigned Prefix (Enterprise) Multihoming Applied bandwidth Load threshold at which bandwidth is increased Delay and loss rates acceptable Uptime requirements Cost of service Flat Rate or Usage Pricing

Queuing Theory and QoS Mean queue depth, and therefore delay Nominal Delay and Jitter Greater Delay, Jitter, and Loss Link utilization

Key issues is supporting SLA Fundamentally, the issue is Bandwidth and Reachability

Key problems in global routing Asymmetric Routes resulting from differences in policy Convergence issues resulting from Differences in policy Algorithms and parameters in routing

Structure of the Internet Fred Baker