7.1 : Pourquoi IPv6 - unice.friutsa.unice.fr/~frati/ipv6_DUT/01-Pourquoi IP v6 v0.2.pdf · Internet Protocol : actuellement en version 4 Adresse IP: ... L’adressage IP 1 réseau

7.1 : Pourquoi IPv6 ?

Les faiblesses d’IPv4Tout devient connectéComment faciliter les configurations ?

2014Eric Levy-Abégnoli (Cisco)Stéphane Frati (Unice)

Ce document ne peut être reproduit sans l’autorisation de [email protected] et [email protected]

Les faiblesses d’IPv4

Historique

D’où vient ce protocole IP: Internet Protocol ?

Qu’utilise-t-on aujourd’hui pour faire communiquer deux équipements connectés ? IPv4 ?

IPv6 sans le savoir ?

Comment attribue-t-on une adresse IP sur un équipement ?

mailto:[email protected]



3

Un peu d’histoire Internet…




• 1957: The USSR launches Sputnik, the first artificial earth satellite. In response, the UnitedStates forms the Advanced Research Projects Agency (ARPA) within the Department of

Defense (DoD) to establish a U.S. lead in science and technology.• 1962: Paul Baran publishes the paper “On Distributed Communications Networks,” a

predecessor to the concept of packet-switching networks.• 1969: ARPANET is commissioned by the DoD for research into networking. The first node

(a mainframe computer) is at the University of California Los Angeles (UCLA) NetworkMeasurements Center. The next three nodes consisted of Stanford Research Institute

(SRI), the University of California Santa Barbara (UCSB), and the University of Utah. The first router is an Information Message Processor (IMP), a Honeywell 516mini-computer with 12K of memory developed by Bolt Beranek and Newman, Inc. (BBN).

• 1969: The first Request for Comments (RFC) is written: “Host Software,” by Steve Crocker.• 1971: Fifteen nodes (23 hosts) are on the ARPANET: UCLA, SRI, UCSB, University of Utah,

BBN, Massachusetts Institute of Technology (MIT), RAND Corporation, System Development Corporation (SDC), Harvard University, MIT’s Lincoln Lab, Stanford University, University of Illinois at Urbana-Champaign, Case Western Reserve University,Carnegie-Mellon University, and NASA/Ames Research Center.

• 1971: Ray Tomlinson of BBN invents an email program to send messages across adistributed network.

• 1973: Bob Metcalfe’s Harvard Ph.D. thesis outlines the idea for Ethernet.

RFC 2235: Hobbes Internet Timeline




• 1973: The File Transfer Protocol (FTP) specification is written (RFC 454).• 1974: Vint Cerf and Bob Kahn publish the paper “A Protocol for Packet Network

Intercommunication,” which specified in detail the design for Transmission ControlProtocol (TCP).

• 1982: ARPA establishes TCP/IP as the protocol suite for the ARPANET. This leads to one ofthe first definitions of an “Internet” as a connected set of networks that use TCP/IP.

• 1982: The External Gateway Protocol (RFC 827) specification is written. EGP is used as therouting protocol between networks and is later replaced by Border Gateway Protocol

(BGP) in 1994 (RFC 1656).• 1983: The Internet transitions from Network Control Protocol (NCP) to TCP/IP on January 1.• 1984: The Domain Name System (DNS) is introduced with RFC 920.• 1984: The number of hosts on the Internet breaks 1000.• 1986: The National Science Foundation Network (NSFNET) initiates operations with a

backbone speed of 56 kbps.• 1987: The number of hosts on the Internet breaks 10,000.• 1988: The NSFNET backbone is upgraded to T1 (1.544 Mbps).• 1988: Internet Relay Chat (IRC) is developed by Jarkko Oikarinen.





• 1988: The NSFNET backbone is upgraded to T1 (1.544 Mbps).• 1989: The number of hosts on the Internet breaks 100,000.• 1991: The World Wide Web (WWW) is released by CERN; it was developed by

Tim Berners-Lee.• 1991: The NSFNET backbone is upgraded to T3 (44.736 Mbps).• 1992: The number of hosts on the Internet breaks 1,000,000.• 1992: The term “surfing the Internet” is coined by Jean Armour Polly..• 1994: Shopping on the Internet begins.• 1995: WWW surpasses FTP as the service with the greatest amount of traffic on the

Internet.• 1995: Online dialup providers Compuserve, America Online, and Prodigy begin to provide

Internet access.• 1995: The Vatican comes online.• 1996: MCI upgrades its Internet backbone, bringing the effective speed from 155 Mbps

to 622 Mbps.• 1996: The WWW browser war, fought primarily between Netscape and Microsoft,

rushes in a new age in software development, whereby new releases are made quarterly with the help of Internet users eager to test upcoming (beta) versions.

• 1997: The number of hosts on the Internet breaks 19,000,000.• 2012: The number of hosts on the Internet breaks 900,000,000





7

Rappels: IP dans le modèle OSI

Network layer

Transport layer

Session layer

Presentation layer

Application layer

Data Link layer

Physical layer

3

4

5

6

7

2

1




L’@dressage IP

Internet Protocol : actuellement en version 4

Adresse IP:

32 bits utilisés, écriture en 4 fois 8 bits.

11000000.10101000.00001010.10000010 =192.168.10.130

L’adressage d’une machine/d’un réseau =@ IP + masque sous-réseau



Format de l’adresse IP


L’adressage IP

1 réseau IP = 1 plage (un « range ») d’adresses IP constituée : d’une adresse définissant le réseau

(première adresse de la plage – e.g. 192.168.10.0)

d’une adresse définissant le broadcast réseau (la dernière adresse de la plage – e.g. 192.168.10.255)

d’adresses des hôtes uniques(toutes les autres adresses e.g. de 1 à 254)NB: en général, la première ou la dernière adresse est réservée à la passerelle par défaut (« default gateway »).




Donc, en résumé, qu’est-ce qu’une “IP address” ?

Toute interface réseau connectée directement à l’Internet (ou à tout réseau IP) est identifiée par une adresse unique de 32 bits

L’adresse est divisée dans une partie qui adresse le réseau (netid) et une partie qui adresse la machine hôte (hostid)

Si l’on prend une adresse IP et, que l’on mette à 1 tous les bits de la partie réseau et à zéro tous les bits de la partie hôte, alors on obtient le masque du réseau




Comment organiser tout celà: … et pourquoi pas des Classes ?

Traditionnellement, les réseaux IP furent d’abord organisés en classes dont la partie correspondant à l’adresse de réseau utilisait 8, 16 ou 24 bits.

IP addresses - net mask length Class A 1.0.0.0 - 126.255.255.255 255.0.0.0 = /8 Class B 128.0.0.0 - 191.255.255.255 255.255.0.0 = /16 Class C 192.0.0.0 - 223.255.255.255 255.255.255.0 = /24 Class D 224.0.0.0 - 239.255.255.255 (multicast) Class E (experimental)

Le premier bit mis à zéro en partant des bits de poids fort déciderait de l’appartenance à une classe

Les adresses IP n’appartenant pas à ces groupes sont réservées pour d’autres utilisations




Address classes

Class A 0 netid hostid

Class C 1 netid hostid

Class D 1 Multicast group ID

Class E (reserved for future use)

Class B 1 netid hostid0

1 0

1 1 0

1 1 1 1

7 bits

14 bits

21 bits

28 bits

28 bits




IP Address Classes and Class Characteristics and Uses

IP

Addr

ess

Class

Fraction of

Total IP

Address

Space

Number

Of

Network

ID Bits

Number

Of Host

ID Bits

Intended Use

Class

A1/2 8 24

Unicast addressing for very large

organizations with hundreds of

thousands or millions of hosts to

connect to the Internet.

Class

B1/4 16 16

Unicast addressing for medium-to-

large organizations with many

hundreds to thousands of hosts to

connect to the Internet.

Class

C1/8 24 8

Unicast addressing for smaller

organizations with no more than

about 250 hosts to connect to the

Internet.

Class

D1/16 n/a n/a IP multicasting.

Class

E1/16 n/a n/a Reserved for “experimental use”.




Division of IPv4 Address Space Into Classes

« C’est de cette mauvaise distribution que viendra la pénurie »…




Attention:Some reserved IP Addresses

First and last number in every subnet

127.0.0.0/8 The localhost network

10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16 Unroutable, Internal Use only see following private%public

adresses and NAT sections

224.0.0.0/8 Multicast see following slide

255.0.0.0/8 Broadcast




An Example of an IP Address

C0.80.17.CB or11000000100000000001011111001011

1100 0000.1000 0000.0001 0111.1100 1011 192.128.23.203

Class C Subnet 24 bits for the network 8 bits for the host

192.128.23.203




TODO Scénario 1: A veut dialoguer avec B situé sur le même réseau

Internet

Host B

192.168.3.125

Host A

192.168.3.5

Adresse de réseau

192.168.3.0/24

de 192.168.3.0 à

192.168.3.255 (exclus)




Host A want to contact Host B on same network

Internet

Host B

192.168.3.125

Host A

192.168.3.5

Network Address

192.168.3.0/24

between 192.168.3.0 and

192.168.3.255 (excluded)

ETH

IP

TCP/UDP

APPLI

How does Host A know Host B

is in the same network ?




How does Host A know Host B is in the same network ?

A wants to talk to B: Is B in the same network ? @B 192.168.3.125

& 255.255.255.0

= 192.168.3.0

Operation & « Logical AND » with subnet mask and IP@ A compares its own result

@A 192.168.3.5& 255.255.255.0

= 192.168.3.0

If results are identical, A and B belongs to the same subnet

NB: Remains the need to get its MAC address ARP protocol



Address Resolution Protocol


Host A want to contact Host B on same network : building the eth frame

Internet

Host B

192.168.3.125

Host A

192.168.3.5

DST MAC

@MAC(B)

SRC MAC

@MAC(A)

ETH

IP

TCP/UDP

APPLI

After ARP request from A/reply from B, Host A sends that frame on the wire :

SRC IP

@IP(A)

DST IP

@IP(B)

SRC TCP

…

DST TCP

…

… …




Host A want to contact Host B but NOT on same segment

Internet

Host B

212.20.3.125

Host A

192.168.3.5

Router R (DGW) Address

192.168.3.1

ETH

IP

TCP/UDP

APPLI

How does Host A know Host B

is in a different network ?




Host A want to contact Host B but NOT on same segment

Internet

Host B

212.20.3.125

Host A

192.168.3.5

ETH

IP

TCP/UDP

APPLI

DST MAC

@MAC(R1)

SRC MAC

@MAC(A)

After ARP request from A/reply from R, Host A sends that frame on the wire :

SRC IP

@IP(A)

DST IP

@IP(B)

SRC TCP

…

DST TCP

…

… …

Router R1

(DGW) Address

R1=192.168.3.1

R1



What if need additional hop(s) ?

Host B

212.20.3.125

Host A

192.168.3.5

ETH

IP

TCP/UDP

APPLI

After ARP request from A/reply from R1i, Host A sends that frame on the wire :

Router R1int

R1i= 192.168.3.1

Router R1ext

R1e= 134.59.22.21

Router R2int

R2i= 212.20.3.1

Router R2ext

R2e= 134.59.22.22

1

DST MAC

@MAC(R1i)

SRC MAC

@MAC(A)

SRC IP

@IP(A)

DST IP

@IP(B)

SRC TCP

…

DST TCP

…

… …1

2 3

DST MAC

@MAC(R2e)

SRC MAC

@MAC(R1e)

SRC IP

@IP(A)

DST IP

@IP(B)

SRC TCP

…

DST TCP

…

… …2

DST MAC

@MAC(B)

SRC MAC

@MAC(R2i)

SRC IP

@IP(A)

DST IP

@IP(B)

SRC TCP

…

DST TCP

…

… …3

reply …


Au fait, seules les adresses publiques sont routables sur Internet…

RFC1918: Use of Network Address Translation

Mapping/swap of addresses (done by a router/firewall)

Some Basic Uses of NAT

Coping with the shortage of external (public) IPv4 addresses

Hiding internal addresses scheme

Providing external services with hosts in internal networks when there are private IP addresses




Exemple de ce qui se passe dans votre CrétinBox…

Dynamic Source IP Address Translation

Internal network External network

192.89.38.200192.168.1.101192.168.100.101

Translated packet

SRC: 192.89.38.200: 80

DST: 192.168.1.101: 9057

4

Reply packet

SRC: 192.89.38.200: 80

DST: 212.20.1.50: 9345

3

Translated packet

SRC: 212.20.1.50: 9345

DST: 192.89.38.200: 80

2

Source packet

SRC: 192.168.1.101: 9057

DST: 192.89.38.200: 80

1

Translation back

into source IP

Dynamic source NAT

@ doivent être uniques pour être routables @ réutilisables mais NON-routables



Fin des révisions

…ce n’étaient que des révisions


Back to: the IPv4 Address

• 32 bits, 232 possible addresses

• 4,294,967,296 hosts

• But in reality, it’s a lot less …

• Must understand address pool allocation scheme

• Or in reality, is it a lot more?

• Must understand address “true” meaning and

mechanisms built around it

IPv4




Pool allocation System (“Par qui et comment sont allouées les tranches d’addresses ?”)

• IANA allocates to RIR (/8)– RIR maintains a pool of addresses

– Attempts to maximize aggregation within pool•Short-term reservations

•Sparse allocation

• RIRs allocate to LIRs/ISPs (/16)– When pool runs low, RIR receives more from IANA

– Subsequent allocations to existing ISPs cannot be aggregated

• ISP allocate to enterprise (/24) or residential (individual addresses)




Pool Allocation Scheme in IPv4

Registries

Level FourEnterprise

IANA

ISP Org

31

APNICRIPENCCARINLACNICAFRINIC

/8

/16

/24




Pool Allocation Scheme

Registries

Level FourEnterprise

IANA

ISP Org

IPv4Pool Empty

IPv4 Pools Running Out

32

APNICRIPENCCARINLACNICAFRINIC

/8

/16

/24




It’s a lot less(than 4 billions to allocate)

• It’s not really addresses which are allocated, it’s prefixes

• Lots of holes

• Lots of waste

• Lots of unused




Pool Allocation SchemeStatus

IANA Unallocated Address Pool Exhaustion: 03-Feb-2011

Projected RIR Address Pool Exhaustion Dates:

RIR Projected Exhaustion Date Remaining Addresses in RIR Pool (/8s)

APNIC: 19-Apr-2011 (actual) 0.8650 RIPE NCC: 14-Sep-2012 (actual) 0.9004 ARIN: 20-Apr-2014 2.3146 LACNIC: 29-Aug-2014 2.4774 AFRINIC: 14-Aug-2020 3.7242




RIRs Status




It’s also a lot more(than 4 billions addressable hosts)

− An address is both an identifier and a locator

− The locator can be shared among many identifiers.

− Separating locator and identifier provides a multiplier factor (NAT, PAT, Tunnels, LISP, etc.)

− Addresses also only need to be known or routable within a particular context.

− Separating contexts provides another multiplier factor: (VPN, Intranet, Specific applications, etc.)




Mais “Tout devient connecté !...”

L’échange de données prédomine maintenant sur l’ensemble des communications

On se débrouille même pour faire passer de la voix (commutation de circuit) sur un réseau de données (à commutations de paquets)…

Et l’on « a besoin » de tout interconnecté:

« t’es pas connecté: t’es mort » (économiquement parlant…)




Internet Growth Chartsource: www.isc.org




So, do We Really Need a Larger Address Space?

Internet Users or PC~1Billion Emerging population/geopolitical and Address space

Mobile phonesAlready 1 billion mobile phones delivered by the industry

Transportation1 billion automobiles

Internet access in Planes

Consumer devicesBillions of Home and Industrial Appliances




Everything Becomes Connected

2004 20092005 2006 2007 2008 2011 2012 20132010

300 Million Devices

50 Billion

Source: Forrester Research, Cisco

Evolution of the internet




The Industrialization of the Internet…Internet of Things

1%

5%

2%

3%

4%

1997 20072005200320011999

Pro

duct

ivit

y

Business

Phase 1

Consumer

Phase 2

The Network as the

Platform

Collaboration

Video

Virtualization/Data Center




The Industrialization of the Internet…Internet of Things

2011 20132009

1%

5%

2%

3%

4%

1997 20072005200320011999

Pro

duct

ivit

y

Business

Phase 1

Consumer

Phase 2

The Network as the

Platform

Collaboration

Video

Virtualization/Data Center

Industrial

Phase 3

Internet of Things




Sensor/Control Networks are / will be everywhere …with a vast scope of applications

Enable New Knowledge

Improve Productivity

Food & H20 Quality

Energy Saving (I2E)

Predictive maintenance

Enhance Safety & Security

Health

Smart Home

Healthcare

Defense

High-Confidence Transport and assets tracking

Intelligent Building

Smart Grid




Smarter cities




An Industry in Transition

ELEC. CO.

Utility HQ

Premise Residential & Commercial

Distribution Automation (DA)

Substation Automation (SA)

Generation

AMI

123412341234

Electric Vehicle Renewable Generation

Real Time Grid Operations

Customer Engagement Diversified Energy Supply

Next Generation Workforce & Facilities

Data Center

Solar

EDF / ERDF

35 Million 732’000

4’000

1.5 Billion Smart Meters worldwide




Comment faciliter les configurations

Tous ces équipements devront posséder une configuration (adresse/masque/passerelle par défaut/DNS…): comment vont-ils l’obtenir (« automagiquement ») sans erreur ?...

Faut-il être neticien pour : Connecter une CrétinBox à l’Internet via ADSL ? Poster des photos compromettantes sur Facebook ? Installer un téléviseur ? Passer un coup de téléphone ? Trouver une place de parking libre dans Nice ? Brancher son frigo ou son four micro-onde ? Conduire une voiture ?




IPv6 == on veut plus d’adresses et d’automatisation de la configuration

On part d’IPv4 On corrige les lacunes d’IPv4…

… avec compléments d’IPv4 et de nouvelles idées… On rajoute des fonctionnalités manquantes…

On veut de « l’automagique » !

Voyons sur quelques exemples d’où l’on vient: (Pour le nombre d’adresses possibles: déjà vu) Pour la distribution d’@IP




En IPv4: Comment A et B ont-ils obtenu leurs configurations ?

Internet

Host B

Host A

Comment chaque station détermine:• Son adresse (qui doit être unique…)• Son masque de sous-réseau• La passerelle par défaut• Le DNS• …

Solution manuelle• Nécessite certaine expertise et rigueur

pour éviter les doublons…Solution automatique• Serveur DHCP (logiciel ou matériel suppl.)• APIPA




What is DHCP (for IPv4)?

“Dynamic Host Configuration Protocol”

RFC 2131

Automatically assigns IP addresses to devices (i.e. hosts) on your network

Prevents having to manually enter data

Prevents typos that can cause connectivity problems or disrupt the network (e.g., exchanging IP address and gateway address)




DHCP




DHCP Results

Servers should provide address,

netmask,

DNS servers,

Domain name,

and gateway

(and perhaps other options, e.g.: WINS, TFTP,…)

Client will be allowed to use the address for a period of time called a Lease (FR:bail)

…But if no DHCP servers exist on your subnet ?




APIPA pour IPv4

But if no DHCP servers exist on your subnet ?

One host’s additional feature has gone through several name changes : AutoNet, Auto-IP Configuration, IP-Auto Configuration, and Automatic Private IP Addressing (APIPA)

Idea To provide an automagically generated IP address that at

least allows local subnet traffic between hosts on the same segment




DHCP is the default config

DHCP automatically

assigns IP Addresses

and other configuration

information to DHCP

clients: default gateway

DNS

…

But what if no DHCP

server’s answer ?...

new TAB




Configuring TCP/IP to obtain an IP address automatically

Assign IP address

of 192.168.120.133

DHCP Client DHCP Server

Request for IP address

Automatic Private IP Addressing enables the configuration

of IP addresses without using static IP addresses or

installing the DHCP Server service

Automatic Private IP Addressing

generates IP Address

If No IP Address Returned

OR



Where does APIPA come from ?

IPv4 Link-Local Addresses

RFC 3927 – “Dynamic Configuration of IPv4 Link-Local Addresses”

If DHCP fails to provide an IP address

interfaces with Link-Local configurations will auto-assign an address

in the 169.254.0.0/16 range

The client will then send an ARP packet asking for the MAC address thatcorresponds to the randomly-generated IPv4 address.

If any other machine is using that address, the client will generate another randomaddress and try again.

Link-Local is on by default on all interfaces on all Windows platforms, including wireless interfaces

http://wiki.wireshark.org/ARP


Donc on s’attend à retrouver dans IPv6 (« le sauveur »)

Une grande plage d’adresse (« découpable » sans trop de pertes) pour adresser plusieurs dizaines ou centaines de machines au m²

Un grand degré d’automatisation car il faut que cela « ça tombe en marche » au moins pour des communications locales

Une limitation des trafics de broadcasts (pas supportable sur un grand réseau)

Une simplification et une plus grande flexibilité du protocole si on le peut

Plus de robustesse pour plus de sécurité dans ce monde actuels de « hackers »




Introduction terminée..

Nous allons voir dans l’étude du protocole IPv6 (chapitre suivant) si ces objectifs ont été atteints en intégrant toutes ces évolutions de protocoles complémentaires à IPv4 et les nouveaux besoins …

Ensuite nous verrons comment IPv4 et IPv6 coexistent sur des réseaux partagés…



Documents

7.1 : Pourquoi IPv6 - unice.friutsa.unice.fr/~frati/ipv6_DUT/01-Pourquoi IP v6 v0.2.pdf · Internet Protocol : actuellement en version 4 Adresse IP: ... L’adressage IP 1 réseau