What is the Internet?Session 2: Basic Principles

Elena Silenok @silenokCharlie Robbins @nodejitsu

Questions? Just Raise Your Hand

Topics

• Network architecture / Principles

• Protocols (List and Association)

• Relationship between IP Address & DNS

• TLDs, domain lookup, IPv4 vs IPv6, Root Servers

• Routers / BGP / Autonomous Systems

History • Theory of Packet Switching (early 1960’s)

• decentralized network with multiple paths between any two points

• dividing complete user messages into message blocks (packets)

• delivery of these messages by store and forward switching

History • Theory of Packet Switching (early 1960’s)

• decentralized network with multiple paths between any two points

• dividing complete user messages into message blocks (packets)

• delivery of these messages by store and forward switching

• ARPANET, Packet Radio Network and Packet Satellite Network

History • Theory of Packet Switching (early 1960’s)

• decentralized network with multiple paths between any two points

• dividing complete user messages into message blocks (packets)

• delivery of these messages by store and forward switching

• ARPANET, Packet Radio Network and Packet Satellite Network

• Intelligent network or intelligent endpoints?

History • Theory of Packet Switching (early 1960’s)

• decentralized network with multiple paths between any two points

• dividing complete user messages into message blocks (packets)

• delivery of these messages by store and forward switching

• ARPANET, Packet Radio Network and Packet Satellite Network

• Intelligent network or intelligent endpoints?

• End-to-end model

History • Theory of Packet Switching (early 1960’s)

• decentralized network with multiple paths between any two points

• dividing complete user messages into message blocks (packets)

• delivery of these messages by store and forward switching

• ARPANET, Packet Radio Network and Packet Satellite Network

• Intelligent network or intelligent endpoints?

• End-to-end model

• IANA / ICANN

IP addresses• Unique for every computer, 32 bits (IPv6 128 bits)

IP addresses• Unique for every computer, 32 bits (IPv6 128 bits)

• Quad notation (dot notation) - 127.0.0.1

IP addresses• Unique for every computer, 32 bits (IPv6 128 bits)

• Quad notation (dot notation) - 127.0.0.1

• Internet Assigned Number Authority (IANA)

IP addresses• Unique for every computer, 32 bits (IPv6 128 bits)

• Quad notation (dot notation) - 127.0.0.1

• Internet Assigned Number Authority (IANA)

• ~4 billion IPv4 addresses

IP addresses• Unique for every computer, 32 bits (IPv6 128 bits)

• Quad notation (dot notation) - 127.0.0.1

• Internet Assigned Number Authority (IANA)

• ~4 billion IPv4 addresses

• 2001:0db8:85a3:0000:0000:8a2e:0370:7334

IP addresses• Unique for every computer, 32 bits (IPv6 128 bits)

• Quad notation (dot notation) - 127.0.0.1

• Internet Assigned Number Authority (IANA)

• ~4 billion IPv4 addresses

• 2001:0db8:85a3:0000:0000:8a2e:0370:7334

• IPv6 - 2 ^128 addresses (40 undecillion, 282 decillion, 366 nonillion, 920 octillion, 938 septillion, 463 sextillion, 463 quintillion, 374 quadrillion, 607 trillion, 431 billion, 768 million, 211 thousand and 456)

IP address utilization

Domain Names• TLD - Top-Level Domains (.com, .net, .ly)

Domain Names• TLD - Top-Level Domains (.com, .net, .ly)

• 21 Generic (.com, .aero, .biz, .edu, .name, .pro, .xxx, etc.)

Domain Names• TLD - Top-Level Domains (.com, .net, .ly)

• 21 Generic (.com, .aero, .biz, .edu, .name, .pro, .xxx, etc.)

• ~250 Country code (always 2-letter) (.tv, .vc, .uk, .at, .bi, .fm, .ca, .cc, .ly, .jp, etc.)

Domain Names• TLD - Top-Level Domains (.com, .net, .ly)

• 21 Generic (.com, .aero, .biz, .edu, .name, .pro, .xxx, etc.)

• ~250 Country code (always 2-letter) (.tv, .vc, .uk, .at, .bi, .fm, .ca, .cc, .ly, .jp, etc.)

• 17 Internationalized (.рф, .香港, .ไทย, !"#$%.)

Domain Names• TLD - Top-Level Domains (.com, .net, .ly)

• 21 Generic (.com, .aero, .biz, .edu, .name, .pro, .xxx, etc.)

• ~250 Country code (always 2-letter) (.tv, .vc, .uk, .at, .bi, .fm, .ca, .cc, .ly, .jp, etc.)

• 17 Internationalized (.рф, .香港, .ไทย, !"#$%.)

• Operated by IANA

Domain Name System

• Distributed database - Internet “phone book”

Domain Name System

• Distributed database - Internet “phone book”

• Translation between IP addresses and domain names

Domain Name System

• Distributed database - Internet “phone book”

• Translation between IP addresses and domain names

• Invented in 1983, “hosts” file at SRI before

Domain Name System

• Distributed database - Internet “phone book”

• Translation between IP addresses and domain names

• Invented in 1983, “hosts” file at SRI before

• BIND (Berkeley Internet Name Domain) Server

DNS Architecture

Root NameserversLetter IPv4 address IPv6 address AS-number[3] Old name Operator Location

#sites (global/local)[4]Software

A 198.41.0.4 2001:503:ba3e::2:30 AS19836 ns.internic.net VeriSign Distributed using anycast6/0

BIND

B192.228.79.201 (since January 2004; originally was 128.9.0.107)[5]

2001:478:65::53 (not in root zone yet)

none ns1.isi.edu USC-ISI Marina Del Rey, California, U.S.0/1

BIND

C 192.33.4.12 AS2149 c.psi.net Cogent Communications

Distributed using anycast6/0

BIND

D 128.8.10.90 AS27 terp.umd.edu University of Maryland College Park, Maryland, U.S.1/0

BIND

E 192.203.230.10 AS297 ns.nasa.gov NASA Mountain View, California, U.S.1/0

BIND

F 192.5.5.241 2001:500:2f::f AS3557 ns.isc.org Internet Systems Consortium

Distributed using anycast2/47

BIND 9[6]

G 192.112.36.4 AS5927 ns.nic.ddn.mil Defense Information Systems Agency

Distributed using anycast6/0

BIND

H 128.63.2.53 2001:500:1::803f:235 AS13 aos.arl.army.mil U.S. Army Research Lab

Aberdeen Proving Ground, Maryland, U.S.2/0

NSD

I 192.36.148.17 2001:7fe::53 AS29216 nic.nordu.net Autonomica Distributed using anycast36

BIND

J192.58.128.30 (since November 2002; originally was 198.41.0.10)

2001:503:c27::2:30 AS26415 VeriSign Distributed using anycast63/7

BIND

K 193.0.14.129 2001:7fd::1 AS25152 RIPE NCC Distributed using anycast5/13

NSD[7]

L199.7.83.42 (since November 2007; originally was 198.32.64.12)[8]

2001:500:3::42 AS20144 ICANN Distributed using anycast37/1

NSD[9]

M 202.12.27.33 2001:dc3::35 AS7500 WIDE Project distributed using anycast5/1

BIND

Root Server Geography

Internet Data Flow

OSI ModelData unit Layer Function

Hostlayers

Data

7. Application Network process to application

Hostlayers

Data 6. Presentation Data representation, encryption and decryption, convert machine dependent data to machine independent data

Hostlayers

Data

5. Session Interhost communication

Hostlayers

Segments 4. Transport End-to-end connections and reliability, flow control

Medialayers

Packet 3. Network Path determination and logical addressing

Medialayers Frame 2. Data Link Physical addressingMedialayers

Bit 1. Physical Media, signal and binary transmission

TCP/IP• End-to-End Principle (smart ends, dumb network)

• Robustness Principle (send carefully, accept liberally)

TCP/IP• End-to-End Principle (smart ends, dumb network)

• Robustness Principle (send carefully, accept liberally)

• IP is “best effort” delivery

TCP/IP• End-to-End Principle (smart ends, dumb network)

• Robustness Principle (send carefully, accept liberally)

• IP is “best effort” delivery

• TCP (on top of IP) is connection-oriented and reliable

TCP/IP• End-to-End Principle (smart ends, dumb network)

• Robustness Principle (send carefully, accept liberally)

• IP is “best effort” delivery

• TCP (on top of IP) is connection-oriented and reliable

■ data arrives in-order■ data has minimal error (i.e. correctness)■ duplicate data is discarded■ lost/discarded packets are resent■ includes traffic congestion control

Routers / BGP

Border Gateway Protocol (BGP)

• Protocol backing the core routing decisions on the Internet

Border Gateway Protocol (BGP)

• Protocol backing the core routing decisions on the Internet

• Table of IP networks (‘prefixes’, e.g. 44.0.0.0/8)

Border Gateway Protocol (BGP)

• Protocol backing the core routing decisions on the Internet

• Table of IP networks (‘prefixes’, e.g. 44.0.0.0/8)

• Replaced Exterior Gateway Protocol (EGP) to remove reliance on NSFNet network

Border Gateway Protocol (BGP)

• Protocol backing the core routing decisions on the Internet

• Table of IP networks (‘prefixes’, e.g. 44.0.0.0/8)

• Replaced Exterior Gateway Protocol (EGP) to remove reliance on NSFNet network

• Fully decentralized routing

Border Gateway Protocol (BGP)

• Protocol backing the core routing decisions on the Internet

• Table of IP networks (‘prefixes’, e.g. 44.0.0.0/8)

• Replaced Exterior Gateway Protocol (EGP) to remove reliance on NSFNet network

• Fully decentralized routing

• Used by ISPs, not users

Autonomous Systems (AS)

• Collection of connected IP routing prefixes

Autonomous Systems (AS)

• Collection of connected IP routing prefixes

• AS number (ASN) uniquely defines each network on the Internet

Autonomous Systems (AS)

• Collection of connected IP routing prefixes

• AS number (ASN) uniquely defines each network on the Internet

• Over 37 000 in 2011 (vs ~5000 in 1999)

Autonomous Systems (AS)

• Collection of connected IP routing prefixes

• AS number (ASN) uniquely defines each network on the Internet

• Over 37 000 in 2011 (vs ~5000 in 1999)

• Assigned by IANA

Autonomous Systems (AS)

• Collection of connected IP routing prefixes

• AS number (ASN) uniquely defines each network on the Internet

• Over 37 000 in 2011 (vs ~5000 in 1999)

• Assigned by IANA

• Transit and connectivity (eXchange Points)

BGP tables

Source: Bill Cheswick, Lumeta Corp

Internet Traffic

Source: Stephen Eick, Bell Labs / Visual Insight

Internet Authorities

• IANA (Jon Postel at ISI)

• Internet Assigned Numbers Authority

• ICANN (founded 1998)

• Internet Corporation for Assigned Names and Numbers

• COICA (Combating Online Infringement and Counterfeits Act)

Questions/Suggestions?

• Elena Silenok

• silenok@gmail.com, twitter: @silenok

• Charlie Robbins

• charlie@generalassemb.ly, twitter: @nodejitsu