Internet and Intranet Fundamentals

Internet and Intranet Fundamentals

Class 2

Session B

Topics

• The Internet Part I– History– TCP / IP Protocol Suite

Internet History

• Some resources– The Internet Society

• http://www.isoc.org/internet-history/brief.html

– BBN Timeline• http://www.bbn.com/timeline/

Internet History• Late 1950s: ARPA Founded

– (Advanced Research Projects Agency)– J.C.R. Licklider first director of Information

Processing Techniques Office (IPTO)

• Early 1960s: Packet Switching Concepts Outlined– Leonard Kleinrock (UCLA)– Paul Baran, et. al.– Rand Corp.

InternetPacket Switching Theory

• First Paper– L. Kleinrock, "Information Flow in Large

Communication Nets", RLE Quarterly Progress Report, July 1961.

• First Book– L. Kleinrock, Communication Nets: Stochastic

Message Flow and Delay, Mcgraw-Hill (New York), 1964.

Internet History

• 1965: ARPA Study “A Cooperative Network of Time-Sharing Computers”

• 1967: Larry Roberts begins developing Rand concepts at ARPA

• 1967: Packet Switch concept developed -- Interface Message Processor (IMP)

• 1968: ARPA lets RFQ for 4 IMPs

Internet History

• 1969: ARPANET is born– 4 IMPs– UCLA, SRI, UCSB, U. of Utah

• 1969: Network Working Group (NWG) formed to develop protocols

• 1970: Network Control Protocol (NCP) created– precursor to TCP

Internet History

• 1971: Telnet and FTP defined by NWG

• 1971: ARPANET grows to nearly 2 dozen sites

• 1972: Public demonstration of ARPANET

• 1972: First e-mail sent– Ray Tomlinson, Larry Roberts

• 1973: First international ARPANET connections

Internet History

• 1975: Transmission Control Protocol (TCP) defined– NCP not reliable– Robert Kahn (requirements)– Vinton Cerf (detailed design)

• 1975: 63 Nodes– addressing revised– Telnet revised

Internet History

• 1976: First Internet routers

• 1976: CCITT defines X.25– Comite Consultatif Internationale de

Telegraphique et Telephonique– X.25 = Packet Switching

• 1976: Bell Labs develops UUCP– Unix-to-Unix copy

• 1979: USENET established

Internet History

• 1980: 400 hosts, 10,000 users

• 1981: Change from NCP to TCP/IP mandated– must go into effect by Jan 1, 1983

• 1982: DoD builds Defense Data Network based on TCP/IP

• 1983: ARPANET splits into ARPANET and MILNET

Internet History

• 1983: TCP/IP established

• 1983: Nameservers established

• 1983: Desktop workstations introduced and LAN technologies take off

• 1985: DNS established

• 1985: >1,000 hosts

• 1986: NSFNET founded

Internet History

• 1987: 4,000 hobbyist bulletin boards

• 1988: ARPANET exceeds 77 million packets / day

• 1988: ARPANET dismantling begins

• 1989: ARPANET ceases to exist– now called Internet– 100,000 hosts

Internet History

• 1991: Archie, gopher, WAIS

• 1991: Commercial Internet Exchange founded to handle commercial use of Internet

• 1992: 17,000 networks in 33 countries– over 1 million hosts

• 1993: WWW

• 1993: InterNIC created

Internet History

• 1993: 1.5 million hosts in over 100 coutnries

• 1994: US lawmakers consider National Information Infrastructure

• 1994: Commercial users outnumber academic 2-to-1

• July 1994: 3,000,000 hosts

Internet History

• April 1995: Commercial online providers (Compuserve, AOL, Prodigy) offer access to Internet

• July 1995: 20-30 million users estimated

• Nov 1995: Commercial sites index: >15,000

• Nov 1995: Java, JavaScript, VRML

Topics

• Internet Protocols– TCP/IP Overview– Layers– IP Addressing– TCP– UDP– DNS

Internet ProtoclsTCP/IP Overview

• TCP / IP = Transmission Control Protocol / Internet Protocol

• Early 1970s– ARPANET

• Distributed with UC Berkeley UNIX in Early 1980s

• Public Domain, Non-Proprietary, Open Source

Internet ProtocolsLayers

• Four Layer Model– Application– Transport (TCP / UDP)

• contains some Session features

– Network (IP)• actually there are three sublayers

– internet (IP)– convergence– subnet

– Data Link and Physical


• Packet Switching– datagrams

• Nodes– hosts

• end-user machines• clients or servers

– routers• connecting different networks• a router is also a host of sorts


• Connection-Oriented– TCP– reliable two-way, byte stream protocol

• Connectionless– UDP = User Datagram Protocol

• also known as the “Unreliable Datagram Protocol”


Layer Protocls

Application Telnet(login)

FTP(files)

SMTP(mail)

DNS(names)

NTP(time)

NFS(files)

Transport TCP UDP

Internet IP

Network ISO 8802-2

Datalink

Ethernet

IEEE802.3

IEEE802.5

X.25 SLIP PPP

Physical Various

Internet ProtocolsIP Addressing

• Four Bytes Wide

• Dotted Decimal Notation– 128.34.239.56– high order to low order

• or MSB to LSB

• Network Number– can be 1, 2, or 3 bytes long

• Host Number

Internet ProtocolsIP Address Classses

Class High Order Bits ofFirst Byte

Network Range Host Range

0 1 2 3 Low High Low High

A 0 - - - 0.0.0.0 127.0.0.0 0.0.0 255.255.255

B 1 0 - - 128.0.0.0 191.255.0.0 0.0 255.255

C 1 1 0 - 192.0.0.0 223.255.255.0 0 255

D 1 1 1 - 224.0.0.0 239.255.255.255 N/A N/A

E 1 1 1 1 240.0.0.0 255.255.255.255 N/A N/A

Internet ProtocolsIP Addressing

• Reserved Addresses– all bits 0 on network number => this network– all bits 0 on host number => this host (localhost)– multicasting (broadcast) class D– class E reserved

• Subnet Masking– portion of host number used to identify the subnet

Internet ProtocolsTCP

• Reliable, Bidirectional Byte Stream– like a UNIX pipe

• End-to-End Reliability

• Bandwidth Optimization (flow control)

• Ports– source– destination

Internet ProtocolsUDP

• User Datagram Protocol

• Ports (like TCP)

• Length, Checksum, Data– no sequencing or acknowledgment structure– error handling left to applications protocol

• DNS uses UDP

Internet ProtocolsDNS

• Domain Name System

• Distributed– database scattered across thousands of

nameservers

• Top-Level Domains– root domain: .– net, edu, com, org, mil, and country codes (jp)

• FQDN: Fully Qualified Domain Name

DNS Naming Tree

jporgeducom

gonzoim4u

eecs

utexas

.

ucr

Internet ProtocolsDNS

• Address Records (A records)– translates domain names to IP addresses

• Mail Related Resource Records– MX Records

• Caching– local nameservers can cache name-to-address

translations for a period controlled by the authoritative nameserver

DNS Architecture

Server

Resolver Library

Application

functioncall

functionreturn

query reply

query or replyto/from another server

query or reply

IPv6Chief Characteristics

• Replaces IPv4– current IP

• Expands 32 bit addressing to 128 bit

• Autoconfiguration

• QOS Features

• Reduced Overhead

• Authentication/Privacy Provisions

IPv6Development History

• Mid 90s Scare re Address Space– seem to be running out– IPv4 has been updated to avoid this problem

• IETF = Internet Engineering Task Force– recommended IPng (informal name) July 94– RFC 1752

IPv6Design Goals

• Evolutionary Step– smooth transition from IPv4– no disruption– peaceful coexistence

• Plan for Future Applications– high bandwidth

IPv6PDU

• 4-bit Priority Field

• 24-bit Flow Label– QOS

• 16-bit Payload Length

• 8-bit Next Header (same as IPv4)– identifies header immediately following IPv6

header

• 8-bit Hop Limit

• 128-bit Source and Destination Addresses

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Version| Prior | Flow Label | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Payload Length | Next Header | Hop Limit | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + Source Address + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + Destination Address + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

IPv6Extension Headers

• Next Header Field– identifies type of optional extension header

after IPv6 header

• Extension Header Sandwiched between IPv6 and Transport Layer Protocol

• Most Not Examined or Processed by Intermediate Routers– faster forwarding

• Arbitrary Length

IPv6Addressing

• Ample Address Space– 2^^96 times that of IPv4 (2^^32)

– 340,282,366,920,938,463,463,374,607,431,768,211,456

– 665,570,793,348,866,943,898,599 addresses per square meter of Earth surface

• ignoring routing hierarchy

– more pessimistic estimate: 1,564 addresses per square meter of Earth surface

• Keep in Mind Device Control Apps

IPv6Addressing

• Unicast Hierarchy– Registry– Provider– Subscriber– Subnet– Interface

IPv6Addressing

• Anycast– packets routed to “nearest” interface with that

address

• Multicast– Scope Limiting Field

• limits number of hosts to which packet is broadcast

IPv6Security Features

• IPv6 Authentication Header– authentication– integrity– but not confidentiality– addresses spoofing problem

• IPv6 Encapsulating Security Header– integrity– confidentiality

IPv6QOS Capabilities

• Flow Label and Priority Fields

• Flow– sequence of packets from source to destination– requiring special handling by intervening

routers

• Real-Time Service

• Priority– source congestion control (backs off) vs.– non-back off

IPv6Other Improvements

• Expanded Packet Length– IPv4: 64KB packet length– IPv6: 4GB

• “Jumbograms”

• Autoconfiguration– allows a node to discover its own address upon

booting

• 6bone: experimental backbone for IPv6

IPv6Summary

• Good Idea– but no longer urgent

• Will Probably Evolve

Documents

Internet and Intranet Fundamentals