Dr Dr NenadNenadKrajnoviKrajnovićć ee--mail: krajkomail: …telekomunikacije.etf.bg.ac.rs/predmeti/ot4ai/IPv6-osnove.pdf · 2016-04-18 · Razlozi za uvođenje IPv6 Potrošen adresni

IP IP versionversion 66

Dr Dr NenadNenad KrajnoviKrajnoviććee--mail: krajkomail: krajko@@etf.bg.acetf.bg.ac..rsrs

Razlozi za uvođenje IPv6Razlozi za uvođenje IPv6

��Potrošen adresni prostorPotrošen adresni prostor��Mogućnost da se integrišu nove Mogućnost da se integrišu nove

stvari kao što je automatsko stvari kao što je automatsko konfigurisanje, sigurnost i zaštita, konfigurisanje, sigurnost i zaštita,

22

konfigurisanje, sigurnost i zaštita, konfigurisanje, sigurnost i zaštita, QoSQoS

��Širenjem Interneta sve više raznih Širenjem Interneta sve više raznih ureñaja se povezuje na mrežu, kao ureñaja se povezuje na mrežu, kao što su mobilni telefoni (procene što su mobilni telefoni (procene susuda je 2014. bilo 1,75 milijardi da je 2014. bilo 1,75 milijardi smart smart mobilnih telefona)mobilnih telefona)

IPv6IPv6

��Definisan u okviru RFC Definisan u okviru RFC 24602460((specifikacija je dopunjena kroz veći specifikacija je dopunjena kroz veći broj novijih RFCbroj novijih RFC--ova)ova)

��Arhitektura adresiranja je definisana Arhitektura adresiranja je definisana u okviru RFC u okviru RFC 4291 (dopunjena u 4291 (dopunjena u

33

u okviru RFC u okviru RFC 4291 (dopunjena u 4291 (dopunjena u novijim RFCnovijim RFC--ovima)ovima)

��Uvodi 128Uvodi 128--bitni adresni bitni adresni prostorprostor��Modifikuje se format zaglavlja IP Modifikuje se format zaglavlja IP

datagrama u cilju smanjenjadatagrama u cilju smanjenja broja broja poljapolja

IPv6 IPv6 -- nastavaknastavak

��Unapreñen način tretiranja opcija u Unapreñen način tretiranja opcija u okviru zaglavljaokviru zaglavlja

��Uvodi Uvodi se labela koja identifikuje tok se labela koja identifikuje tok podatakapodataka

44

podatakapodataka��Uvedena je ekstenzija koja Uvedena je ekstenzija koja

omogućomogućaava identifikaciju pošiljaoca i va identifikaciju pošiljaoca i zaštitu podataka (AH i ESP)zaštitu podataka (AH i ESP)

AH AH –– Authentication HeaderAuthentication Header

ESP ESP –– Encapsulating Security PayloadEncapsulating Security Payload

Format paketaFormat paketa

++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++

|Version| Traffic Class | Flow Label ||Version| Traffic Class | Flow Label |

++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++

| Payload Length | Next Header | Hop Limit || Payload Length | Next Header | Hop Limit |

++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++

| || |

+ ++ +

| || |

55

| || |

+ Source Address ++ Source Address +

| || |

+ ++ +

| || |

++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++

| || |

+ ++ +

| || |

+ Destination Address ++ Destination Address +

| || |

+ ++ +

| || |

++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++

Format paketa Format paketa -- objašnjenjaobjašnjenja

��VersionVersion –– 4 bita 4 bita –– oznaka verzije (6oznaka verzije (6).).��Traffic ClassTraffic Class –– 8 bita 8 bita –– polje klase polje klase

servisa.servisa.��Flow LabelFlow Label –– 20 bita 20 bita –– labela koja labela koja

66

��Flow LabelFlow Label –– 20 bita 20 bita –– labela koja labela koja identifikuje tok identifikuje tok podatakapodataka; ; definisano definisano u RFC 6437.u RFC 6437.

��Payload LengthPayload Length –– 16 bita 16 bita –– ddužiužinanadela datagrama koji sleddela datagrama koji sledii posle posle osnovnog IPv6 osnovnog IPv6 zaglavlja izražena u zaglavlja izražena u broju broju okteta.okteta.


��Next HeaderNext Header –– 8 bita 8 bita –– identifikuje identifikuje tip zaglavlja koje sledi odmah posle tip zaglavlja koje sledi odmah posle osnovnog zaglavljaosnovnog zaglavlja

77

Višestruko zaglavljeVišestruko zaglavlje

88

Redosled obrade dodatnih Redosled obrade dodatnih

zaglavlja (RFC 2460)zaglavlja (RFC 2460)

Preporučeni redosled

Dodatno zaglavlje Oznaka za next-header

11 HopHop--byby--hop options headerhop options header 00

22 Destination options headerDestination options header 6060

33 Routing headerRouting header 434333 Routing headerRouting header 4343

44 Fragment headerFragment header 4444

55 Authentication header (AH)Authentication header (AH) AH=51AH=51

66 ESP headerESP header ESP=50ESP=50

77 UpperUpper--layer header: layer header: TCPTCPUDPUDP

TCP = 6TCP = 6UDP = 17UDP = 17

99


��Hop LimitHop Limit –– 8 bita 8 bita –– brojač broja brojač broja skokova (nekada se koristilo polje skokova (nekada se koristilo polje TTL); ako vrednost dostigne nulu TTL); ako vrednost dostigne nulu datagram se odbacujedatagram se odbacujedatagram se odbacujedatagram se odbacuje

1010


��SourceSource, Destination Address, Destination Address –– po 128 po 128 bita bita –– IPv6 adresaIPv6 adresa

��Moguće je adresirati 2 na 128Moguće je adresirati 2 na 128--mi mi stepen različitih adresa:stepen različitih adresa:

1111

stepen različitih adresa:stepen različitih adresa:

340,282,366,920,938,463,463,374,607,431,768,211,456340,282,366,920,938,463,463,374,607,431,768,211,456

Tipovi IPv6 adresaTipovi IPv6 adresa

�� Tri tipa adresa:Tri tipa adresa:–– unicastunicast –– označava adresu jednog interfejsa na označava adresu jednog interfejsa na

ureñajuureñaju–– multicastmulticast –– označava grupu interfejsa označava grupu interfejsa

(uglavnom na različitim računarima);(uglavnom na različitim računarima);

1212

(uglavnom na različitim računarima);(uglavnom na različitim računarima);paket poslat na ovu adresu stiže paket poslat na ovu adresu stiže do svihdo svihadresiranih interfejsaadresiranih interfejsa

–– anycastanycast –– označava grupu interfejsa; paket označava grupu interfejsa; paket poslat na poslat na anycast anycast adresu stiže adresu stiže do jednog od do jednog od interfejsainterfejsa opisanih ovom adresom (po pravilu opisanih ovom adresom (po pravilu najbližeg definisano pojmom rastojanja u najbližeg definisano pojmom rastojanja u protokolu rutiranja)protokolu rutiranja)

BroadcastBroadcast adresa?adresa?

��Broadcast Broadcast adresa se više ne koristiadresa se više ne koristi��Tu funkciju obavlja Tu funkciju obavlja multicastmulticast adresaadresa��Adrese sa svim 0Adrese sa svim 0--ma ili svim 1ma ili svim 1--ma u ma u hosthost delu sada postaju regularne delu sada postaju regularne

1313

hosthost delu sada postaju regularne delu sada postaju regularne adreseadrese

Arhitektura adresiranjaArhitektura adresiranja

��Način dodele adrese se značajno Način dodele adrese se značajno razlikuje u odnosu na IPv4razlikuje u odnosu na IPv4

��Svaki interfejs mora da ima barem Svaki interfejs mora da ima barem jednu tzv. jednu tzv. linklink--locallocal adresu a može adresu a može

1414

jednu tzv. jednu tzv. linklink--locallocal adresu a može adresu a može da ima proizvoljan broj drugih adresada ima proizvoljan broj drugih adresa

�� Jedna Jedna unicastunicast adresa može se adresa može se koristiti za više fizičkih interfejsa na koristiti za više fizičkih interfejsa na jednom ureñaju (za jednom ureñaju (za load balancingload balancing))

Način pisanja IPv6 adresaNačin pisanja IPv6 adresa

��Najčešće se koristi format:Najčešće se koristi format:x:x:x:x:x:x:x:xx:x:x:x:x:x:x:x

gde svako “x” predstavlja gde svako “x” predstavlja heksadecimalni zapis 16heksadecimalni zapis 16--bitnog poljabitnog polja

1515

heksadecimalni zapis 16heksadecimalni zapis 16--bitnog poljabitnog polja

FEDC:BA98:7654:3210:FEDC:BA98:7654:3210FEDC:BA98:7654:3210:FEDC:BA98:7654:3210

Način pisanja IPv6 adresaNačin pisanja IPv6 adresa

��U cilju pojednostavljenja, nije U cilju pojednostavljenja, nije neophodno pisati vodeće nule ili veći neophodno pisati vodeće nule ili veći broj nula:broj nula:

1080:0:0:0:8:800:200C:417A ili 1080:0:0:0:8:800:200C:417A ili

1616

1080:0:0:0:8:800:200C:417A ili 1080:0:0:0:8:800:200C:417A ili 1080::8:800:200C:417A1080::8:800:200C:417A

FF01:0:0:0:0:0:0:101 ili FF01::101FF01:0:0:0:0:0:0:101 ili FF01::1010:0:0:0:0:0:0:1 ili ::10:0:0:0:0:0:0:1 ili ::1

Tipovi adresaTipovi adresa

Address type Binary prefix Address type Binary prefix IPv6IPv6

notationnotation

Unspecified 00...0 (128 bits) ::/128Unspecified 00...0 (128 bits) ::/128

Loopback 00...1 (128 bits) ::1/128Loopback 00...1 (128 bits) ::1/128

1717

Multicast 11111111 FF00::/8Multicast 11111111 FF00::/8

LinkLink--local local

unicast 1111111010 FE80::/10 unicast 1111111010 FE80::/10

SiteSite--local local

unicast 1111111011 FEC0::/10 unicast 1111111011 FEC0::/10

Global Global

unicast (unicast (everything elseeverything else))

Dodeljivanje adresaDodeljivanje adresa

��Kombinacija alokacije i automatskog Kombinacija alokacije i automatskog dodeljivanjadodeljivanja

��Adresa mreže se i dalje definiše po Adresa mreže se i dalje definiše po CIDR principuCIDR principu

1818

CIDR principuCIDR principu��Krajnji korisnik svoj adresni blok Krajnji korisnik svoj adresni blok

dobija od ISPdobija od ISP--aa��Definisanje Definisanje host host dela adrese je dela adrese je

automatizovanoautomatizovano

Dodeljivanje adresaDodeljivanje adresa

��Poslednjih 64 bita u IPv6 Poslednjih 64 bita u IPv6 unicast unicast adresi se nazivaju adresi se nazivaju Interface IdentifierInterface Identifieri moraju da budu jedinstveni unutar i moraju da budu jedinstveni unutar jedne podmreže (jedne podmreže (subnetsubnet).).Interface Identifier Interface Identifier treba treba da bude u da bude u

1919

�� Interface Identifier Interface Identifier treba treba da bude u da bude u modifikovanom EUImodifikovanom EUI--64 64 formatu.formatu.

��RFC 6177 daje preporuku kako deliti RFC 6177 daje preporuku kako deliti adresni prostor.adresni prostor.

��Moguće su i druge mrežne adrese Moguće su i druge mrežne adrese osim /64.osim /64.

Modifikovani EUIModifikovani EUI--64 format64 format

2020

“u” bit označava važnost vrednosti:“u” bit označava važnost vrednosti:

••1 1 –– global scope global scope (adresa se formira na osnovu MAC adrese)(adresa se formira na osnovu MAC adrese)

••0 0 –– local scopelocal scope (adresa se formira na slučajan način)(adresa se formira na slučajan način)

Lokalne adreseLokalne adrese

�� Link localLink local –– FFEE80::/1080::/10–– Predviñena za adresiranje na jednom Predviñena za adresiranje na jednom linku.linku.–– Koristi se za automatsko dodeljivanje adresa, Koristi se za automatsko dodeljivanje adresa,

otkrivanje suseda ili kada nema otkrivanje suseda ili kada nema rutera.rutera.–– Ruter ne sme da prosleñuje pakete sa ovom Ruter ne sme da prosleñuje pakete sa ovom

2121

–– Ruter ne sme da prosleñuje pakete sa ovom Ruter ne sme da prosleñuje pakete sa ovom adresom.adresom.

Lokalne adreseLokalne adrese

��Site localSite local –– FEC0::/10FEC0::/10––Predviñenja za adresiranje unutar Predviñenja za adresiranje unutar

jednog jednog sitesite--a.a.––Ruter Ruter ne sme da propušta pakete sa ne sme da propušta pakete sa

2222

––Ruter Ruter ne sme da propušta pakete sa ne sme da propušta pakete sa ovom ovom adresom.adresom.

––RFC 3879 preporučuje da se ovako RFC 3879 preporučuje da se ovako formirane adrese NE koriste!!!formirane adrese NE koriste!!!

Globalna Globalna unicast unicast adresaadresa

Adresni blok koji se trenutno distribuiraAdresni blok koji se trenutno distribuira

2001::/162001::/16

2323

Više adresa po jednom Više adresa po jednom

interfejsuinterfejsu�� IPv6 dozvoljava da jedan fizički IPv6 dozvoljava da jedan fizički

interfejs ima više IPv6 adresa:interfejs ima više IPv6 adresa:inet6 2001:inet6 2001:bafabafa::221:0:225:90ff:fe3c:40ca 1:0:225:90ff:fe3c:40ca prefixlenprefixlen 64 64 scopeidscopeid 0x0<global>0x0<global>inet6 fe80::225:90ff:fe3c:40ca inet6 fe80::225:90ff:fe3c:40ca prefixlenprefixlen 64 64 scopeidscopeid 0x20<link>0x20<link>inet6 2001:inet6 2001:bafabafa::221::1::44 prefixlenprefixlen 64 64 scopeidscopeid 0x0<global>0x0<global>inet6 2001:inet6 2001:bafabafa::221::1::44 prefixlenprefixlen 64 64 scopeidscopeid 0x0<global>0x0<global>

IPv6 is enabled, linkIPv6 is enabled, link--local address is FE80::3E08:F6FF:FE8C:943F local address is FE80::3E08:F6FF:FE8C:943F Global unicast address(Global unicast address(eses):):2001:2001:BAFA:2BAFA:21::11::155, subnet is 2001:, subnet is 2001:BAFABAFA::221::/64 1::/64

Joined group address(Joined group address(eses):):FF02::1FF02::1FF02::2FF02::2FF02::1:FF00:13FF02::1:FF00:13FF02::1:FF8C:943FFF02::1:FF8C:943F

2424

Multicast Multicast adresaadresa

2525

Rezervisane Rezervisane multicast multicast adreseadrese

Rezervisana multicastadresa

Opis namene

FF02::1 Svi nodovi na linku (link-local scope).

FF02::2 Svi ruteri na linku.

FF02::9 Svi routing information protocol (RIP) ruteri na linku.ruteri na linku.

FF02::1:FFxx:xxxx Sve solicited-node multicast adrese koje se koriste za autoconfiguration hosta ineighbor discovery (slično ARP-u kodIPv4).

xx:xxxx je 24 bita najmanje težine odgovarajuće unicast ili anycast adrese noda.

FF05::101 Svi Network Time Protocol (NTP) serveri.

2626

IPv6 Multicast adrese - Scope

• Scope je polje dužine 4 bita koje se koristi za definisanje oblasti važenja

multicast adrese

• Scope (nepotpuna lista):

• 0 Reserved

• 1 Interface-Local scope

Flag Group ID1111 1111

8 bits

Scope

4 bits 4 bits 112 bits

• 1 Interface-Local scope

• 2 Link-Local scope

• 5 Site-Local scope

• 8 Organization-Local

scope

• E Global scope

2727

IPv6 Multicast adrese - Flag

• Flag T

• 0 - Permanent, well-known multicast address assigned by IANA.

• Includes both assigned and solicited-node multicast addresses.

Flag Group ID1111 1111

8 bits

Scope

4 bits 4 bits 112 bits

00PT

• 1 - Non-permanently-assigned, “dynamically" assigned multicast

address.

• Jedan primer je adresa FF18::BAFA:2356, koja se koristi za

multicast aplikacije unutar organizacije.

• Flag P - Prefix for unicast-based assignments

2828

Assigned IPv6 Multicast Addresses

IPv6 AdreseIPv6 Adrese

MulticastMulticast

FF00::/8 FF02::1:FF00:0000/104

AssignedAssigned Solicited-NodeSolicited-Node

• RFC 2375, IPv6 Multicast Address Assignments, defines the initial assignment of IPv6 multicast addresses that have permanently assigned Global IDs.

• Reference for assigned multicast addresses:

• (IANA) IPv6 Multicast Address Space Registry -http://www.iana.org/assignments/ipv6-multicast-addresses/ipv6-multicast-addresses.xhtml

2929

Assigned Multicast Addresses with Link-local Scope

Prefix Flag Scope Predefined Group ID Compressed

Format

Description

(IPv6 assumed)

FF 0 2 0:0:0:0:0:0:1 FF02::1 All-devices

FF 0 2 0:0:0:0:0:0:2 FF02::2 All-routers

Flag = 0, Assignedmulticast

Scope = 2, Link-local scope

FF 0 2 0:0:0:0:0:0:5 FF02::5 OSPF routers

FF 0 2 0:0:0:0:0:0:6 FF02::6 OSPF DRs

FF 0 2 0:0:0:0:0:0:9 FF02::9 RIP routers

FF 0 2 0:0:0:0:0:0:A FF02::A EIGRP routers

FF 0 2 0:0:0:0:0:1:2 FF02::1:2 DHCP

servers/relay

agents

3030

Assigned Multicast Addresses with Site-local Scope

Prefix Flag Scope Predefined Group ID Compressed

Format

Description

(IPv6 assumed)

FF 0 5 0:0:0:0:0:0:2 FF05::2 All-routers

Flag = 0, Assigned multicast

Scope = 5, Site-local scope

FF 0 5 0:0:0:0:0:0:2 FF05::2 All-routers

FF 0 5 0:0:0:0:0:1:3 FF05::1:3 All DHCP servers

• Koristi se za komunikaciju unutar sajta, uz mogućnost rutiranja unutar

sajta.

• Da bi IPv6 multicast rutiranje funkcionisalo, mora da se aktivira:

Router(config)# ipv6 multicast-routing

3131

“All IPv6 Devices” Assigned Multicast Address

• FF02::1 – All IPv6 Devices• All IPv6 devices, including the

FF02::1 FE80::225:90ff:fe3c:40ca Rest of IPv6 Packet

DestinationIPv6 Address

Source IPv6 Address(Link-local address) Router(config)# ipv6 unicast-routing

ICMPv6 ICMPv6 Router AdvertisementRouter Advertisement

• All IPv6 devices, including the router, belong to this group.

• Every IPv6 device will listen and process packets to this address.

• Isn’t this the same as a broadcast?

• No, because it maps to a Layer 2 MAC address which is more efficient…

ICMPv6 ICMPv6 Router Router

AdvertisementAdvertisement

3232

“All IPv6 Routers” Assigned Multicast Address

• FF02::2 – All IPv6

FF02::2 FE80::12:3456:7890:BAFA Rest of IPv6 Packet

DestinationIPv6 Address

SourceIPv6 Address Router(config)# ipv6 unicast-routing

ICMPv6 ICMPv6 Router SolicitationRouter Solicitation

• FF02::2 – All IPv6 Routers

• All IPv6 routers belong to this group. (Process these packets.)

• Used by devices to communicate with an IPv6 Router.

ICMPv6 Router

Solicitation

3333

Router# show ipv6 interface gigabitethernet 0/0

GibabitEthernet0/0 is up, line protocol is up

IPv6 is enabled, link-local address is FE80::fe3c:40ca

Global unicast address(es):

2001:9:BAFA::fe3c:40ca, subnet is 2001:B9:BAFA::/64

Joined group address(es): Member of these Multicast GroupsMember of these Multicast Groups

Verifying IPv6 Multicast Addresses on the Router

FF02::1

FF02::2

FF02::5

FF02::6

FF02::1:FF00:1

All-IPv6 devices on this link

All-IPv6 routers on this link: IPv6 routing enabled

Solicited-node multicast addresses

• FF02 – “2” means link-local scope• What is a solicited node multicast address?

OSPFv3 All OSPF Routers (similar to 224.0.0.5)

OSPFv3 All DR Routers (similar to 224.0.0.6)

3434

Solicited-Node IPv6 Multicast adresa

IPv6 AdreseIPv6 Adrese

MulticastMulticast

FF00::/8 FF02::1:FF00:0000/104

AssignedAssigned Solicited-NodeSolicited-Node

• Pored svake unicast adrese koja se dodeli interfejsu, uređaj će imati i

specijalnu multicast adresu koja je poznata kao solicite-node

multicast adresa.

Unicast: GUA, Link-Local,IUnicast: GUA, Link-Local,I

3535

Solicited-Node Multicast adresa

Unicast Addresses Solicited Node

Multicast

Global Unicast 2001:DB9:BAFA:1::300 FF02::1:FF00:300

Link-local unicast FE80::5555:6666:7777:8888 FF02::1:FF77:8888

PC2

Šta je solicited-node multicast adresa?• A Layer 3 multicast address with link-local scope “FF02” (within the

subnet/VLAN).• There is a solicited node multicast address for every IPv6 unicast (or

anycast) address including:• Global Unicast Address (GUA)• Link-local Address

• Used in ICMPv6 Neighbor Discovery messages during:• Address Resolution – Similar to ARP for IPv4• Duplicate Address Detection (DAD) – Similar to gratuitous ARP

for IPv43636


Multicast

Global Unicast 2001:DB9:BAFA:1::300 FF02::1:FF00:300

Link-local

unicast

FE80::5555:6666:7777:8888 FF02::1:FF77:8888

Solicited-Node Multicast adresa

PC2

Kako se kreiraju?• Postoji direktna veza izmeñu unicast/anycast adrese i njima

odgovarajuće solicited-node multicast adrese.• Solicited-node multicast adresa formira se od:

• Prefiksa FF02:0:0:0:0:1:FF00::/104FF02:0:0:0:0:1:FF00::/104 (FF02::1:FFFF02::1:FFxx:xxxx).• Na taj prefiks se dodaju 24 bita najnižeg prioriteta

unicast/anycast adrese.• Kao i ostale multicast adrese i solicited-node multicast adresa se

mapira u odgovarajuću Ethernet MAC adresu.

3737

Interface ID

FF02 0000 0000 0000 0000 0001 FF

Global Routing Prefix 24 bits

PC2’s Global Unicast Address

PC2’s IPv6 Solicited-Node Multicast Address

Copy 24 bits

SubnetID

2001:0DB9:BAFA 0001 0000:0000:00 00:0300

00:0300Ability to filter at the NIC

Kako se kreiraju Solicited-Node Multicast adrese?

PC2’s IPv6 global unicast address: 2001:DB9:BAFA:1::300PC2’s IPv6 solicited-node multicast address: FF02::1:FF00:300PC2’s mapped Ethernet multicast address : 33-33-FF-00-03-00

FF-00-03-00

Copy 32 bits

33-33

Solicited-node Multicast address mapped to Ethernet destination MAC address

the NIC

IPv6 Multicast Low-order 32 bits of IPv6 multicast address mapped to low-order 32 bits of MAC address.

104 bits

3838

Unicast Addresses Solicited Node Multicast

PC A Global

Unicast

2001:DB9:BAFA:1:AAAA::300 FF02::1:FF00:300

PC B Global

Unicast

2001:DB9:BAFA:1:BBBB::300 FF02::1:FF00:300Interface IDGlobal Routing Prefix

40 bits 24 bits

Subnet ID

2001:0DB9:BAFA 0001 AAAA:0000:00 00:0300

Same for both PCs

PC A

Duplirane Solicited-Node Multicast Adrese

•• Although rare, solicited node multicast addresses may not be Although rare, solicited node multicast addresses may not be unique.unique.

•• Possible to have multiple devices with the same solicited node multicast Possible to have multiple devices with the same solicited node multicast

address (and same Ethernet multicast) if the address (and same Ethernet multicast) if the lowlow--order 24 bits order 24 bits matchmatch

•• HighHigh--order order 40 40 bits bits of of iinterfacenterface ID ID will differwill differ..

•• No problem,No problem, ICMPv6 NS ICMPv6 NS contains contains target target unicast address unicast address ..

2001:0DB9:BAFA 0001 AAAA:0000:00 00:0300

2001:0DB9:BAFA 0001 BBBB:0000:00 00:0300

PC A

PC B

3939


Multicast

Ethernet MAC

Global

Unicast

2001:DB9:BAFA:1::300 FF02::1:FF00:300 33-33-FF-00-03-00

PC2

Prednosti korišćenja Solicited-Node Multicast adresa

•• Zašto suZašto su solicitedsolicited--node multicasts node multicasts bolje nego bolje nego broadcast broadcast adrese?adrese?

•• Multicasts Multicasts adrese se mapiraju u adrese se mapiraju u Ethernet MAC Ethernet MAC adrese iadrese i Ethernet NICs Ethernet NICs

(hardware or drivers) (hardware or drivers) mogu da ih filtrirajumogu da ih filtriraju. .

•• Zašto je to dobro?Zašto je to dobro?

Unicast

Link-local FE80::5555:6666:7777:8888 FF02::1:FF77:8888 33-33-FF-77-88-88

4040

Prednosti korišćenja Solicited-Node Multicast adresa

Ethernet Broadcast• Destination MAC Address: Broadcast• Data must be passed to upper layer for processing (ARP for example).

IPv4 or IPv6 Multicast• IP multicast packets can be filtered by the

Ethernet Broadcast

• IP multicast packets can be filtered by the switch, only sending packets to members of that group.• IPv4 - IGMP (Internet Group Management Protocol)

• IPv6 - MLD (Multicast Listener Discovery)

However, Solicited Node Multicasts are forwarded out all ports because of the potentially huge forwarding tables needed to to store these addresses…

IPv4/IPv6 Multicast

IGMP/MLD Snooping

4141


Multicast

Ethernet MAC

Ethernet NIC N/A N/A 00-1B-24-04-A2-1E

Global Unicast 2001:DB8:CAFE:1::200 FF02::1:FF00:200 33-33-FF-00-02-00

Link-local FE80::1111:2222:3333:4444 FF02::1:FF33:4444 33-33-FF-33-44-44

Multicast

(All-IPv6-

FF02::1 N/A 33-33-00-00-00-01

PC2 Processes the following IPv6 and Ethernet MAC Addresses

Ethernet NICs and Solicited-Node Multicasts

24 bits

32 bits

•• Besides its own MAC address, the Ethernet NIC will accept Besides its own MAC address, the Ethernet NIC will accept

multicast addresses created from the:multicast addresses created from the:

•• Solicited node multicast (global unicast address)Solicited node multicast (global unicast address)

•• Solicited node multicast (linkSolicited node multicast (link--local address)local address)

•• Any assigned multicast address such as AllAny assigned multicast address such as All--IPv6IPv6--DevicesDevices..

Devices)

* Ethernet MAC addresses such as IPv4 broadcasts and those associated with other protocols are not shown.

00-1B-24-04-A2-1E

LAN Card © Copyright lamart1971 4242

Router# show ipv6 interface gigabitethernet 0/0

GigabitEthernet0/0 is up, line protocol is up

IPv6 is enabled, link-local address is FE80::FE99:47FF:FE75:C3E0

Global unicast address(es):

2001:DB8:CAFE:1::1, subnet is 2001:DB8:CAFE:1::/64

Joined group address(es):

FF02::1

FF02::2

All-IPv6 devices on this linkAll-IPv6 routers on this link: IPv6 routing enabled

Member of these Multicast Groups

Verifying the Solicited-Node Multicasts

FF02::2

FF02::1:FF00:1

FF02::1:FF75:C3E0

<output omitted for brevity>

Solicited-node multicast address Global Unicast

• FF02 – “2” means link-local scope• Router’s NIC will process destination MAC addresses for assigned and

solicited node multicasts such as 33-33-FF-00-00-01 and 33-33-FF-75-C3-E0 (solicited node)

Solicited-node multicast address link-local

4343

PC1PC2ARP RequestARP Request

Neighbor

Advertisement

Neighbor

Advertisement

11

22

Neighbor

Solicitation

Neighbor

Solicitation

11

22

Know

IPv4, what

is the

MAC?

Know

IPv4, what

is the

MAC?My IPv4!

Here is the

MAC@

My IPv4!

Here is the

MAC@

Know

IPv6, what

is the

MAC?

Know

IPv6, what

is the

MAC?

My IPv6!

Here is the

MAC@

My IPv6!

Here is the

MAC@

ARP

Cache

Neighbor

Cache

33

33

ICMPv6 ND – Address Resolution

ARP ReplyARP Reply

IP IP to data link to data link (MAC) (MAC) address mappingaddress mapping::

ICMPv6 Neighbor Discovery

Neighbor Solicitation

Neighbor Advertisement

IP IP to data link to data link (MAC) (MAC) address mappingaddress mapping::

�� IPv4 IPv4 addresses use addresses use ARPARP

�� IPv6 IPv6 addressing use addressing use ICMPv6 ICMPv6 Neighbor Neighbor

Discovery messagesDiscovery messages

–– Neighbor Neighbor Solicitation Solicitation ((via Solicitedvia Solicited--NodeNode))

–– Neighbor AdvertisementNeighbor Advertisement

�� Devices store this mapping in their Devices store this mapping in their

Neighbor CacheNeighbor Cache4444

Advantages of Solicited-Node Multicast

IPv4 ARP Requests• Destination MAC Address: Layer 2 Broadcast• Data must be passed by NIC to upper layer for

processing – examine target IPv4 address.

Ethernet Ethernet Broadcast Broadcast

passed to upper layerpassed to upper layer

DA: Broadcast ARP Message with Target IPv4 Address

Ethernet ARP Message

Ethernet Multicast Ethernet Multicast

filtered by the NICfiltered by the NIC

IPv6 Address Resolution• Destination IPv6: SolicitedSolicited--Node MulticastNode Multicast• Destination MAC Address: Layer 2 Layer 2 MulticastMulticast

DA: Solicited-

Node MulticastDA: Multicast

ICMPv6 NS with

Target IPv6 Address

Ethernet ICMPv6 NSIPv6

4545

PC1PC2

Neighbor

Advertisement

Neighbor

Advertisement

44

Neighbor

Solicitation

Neighbor

Solicitation

33

Know

IPv6, what

is the

MAC?

Know

IPv6, what

is the

MAC?

My IPv6!

Here is the

MAC?

My IPv6!

Here is the

MAC?

Solicited-Node Example

2001:DB8:CAFE:1::200/64FF02::1:FF00:200 (Solicited Node Multicast)

2001:DB8:CAFE:1::100/64

2001:DB8:CAFE:1::/64

Neighbor Cache

22 55

MAC Address00-21-9B-D9-C6-44

MAC Address00-1B-24-04-A2-1E

2001:DB8:CAFE:1::20000-1B-24-04-A2-1E

PC1> ping 2001:DB8:CAFE:1::200

11

Destination Address:

FF02::1::FF00:200

Destination MAC:

33-33-FF-00-02-00

Target IPv6 Address

2001:DB8:CAFE:1::200

Ethernet ICMPv6 Neighbor SolicitationIPv6

• ICMPv6 NS: Target IPv6 Address (GUA of PC2)• Destination IPv6: SolicitedSolicited--Node MulticastNode Multicast• Destination MAC Address: Layer 2 Layer 2 MulticastMulticast

00-1B-24-04-A2-1E

4646

MLD Querier

General query General query to FF02::1

Listener Report for groupFF3E:40:2001:DB8:CAFE:1:AAAA:AAAA

Never mind, “A” got it.

R1

A B C

Listener Report for groupFF3E:40:2001:DB8:CAFE:1:BBBB:BBBB

Suppressed Listener Report for groupFF3E:40:2001:DB8:CAFE:1:AAAA:AAAA

MLDv2 Joining a Group

(All-IPv6 devices with link-scope)

Source for groupFF3E:40:2001:DB8:CAFE:1:AAAA:AAAAFF3E:40:2001:DB8:CAFE:1:BBBB:BBBB

FF3E:40:2001:DB8:CAFE:1:AAAA:AAAAto FF02::16 (All MLDv2 Routers)

FF3E:40:2001:DB8:CAFE:1:BBBB:BBBBto FF02::16 (All MLDv2 Routers)

FF3E:40:2001:DB8:CAFE:1:AAAA:AAAAto FF02::16 (All MLDv2 Routers)

•• Multicast Listener Discovery (MLDv2) for IPv6 similar to Internet Group Multicast Listener Discovery (MLDv2) for IPv6 similar to Internet Group Management Protocol (IGMPv2) for IPv4.Management Protocol (IGMPv2) for IPv4.

•• Hosts Hosts use use MLD to MLD to dynamically register themselves in dynamically register themselves in a multicast a multicast group on a group on a particular network. particular network.

•• Hosts send Listener Report Hosts send Listener Report messages messages to their to their local multicast router, informing the local multicast router, informing the router as to which multicast addresses it router as to which multicast addresses it wants to wants to receive traffic. receive traffic.

•• Routers configured Routers configured for for MLD (MLD (MLD MLD QueriersQueriers) ) listen to listen to Listener Report Listener Report messages from messages from hosts.hosts.

•• Routers Routers periodically send out queries to discover which multicast groups are still periodically send out queries to discover which multicast groups are still active.active.

4747

MLD QuerierAddress specific query Address specific query for FF3E:40:2001:DB8:CAFE:1:AAAA:AAAA

Listener Done Listener Done for group

R1

A B C

Listener Report Listener Report for group

MLDv2 Leaving a Group

to FF3E:40:2001:DB8:CAFE:1:AAAA:AAAA

I’m done.I’m done. I still want

it!

I still want

it!

Traffic continues forFF3E:40:2001:DB8:CAFE:1:AAAA:AAAA

Is there anyone

else?

Is there anyone

else?

Source for groupFF3E:40:2001:DB8:CAFE:1:AAAA:AAAAFF3E:40:2001:DB8:CAFE:1:BBBB:BBBB

Listener Done Listener Done for groupFF3E:40:2001:DB8:CAFE:1:AAAA:AAAAto FF02::16 (All MLDv2 Routers)

Listener Report Listener Report for groupFF3E:40:2001:DB8:CAFE:1:AAAA:AAAAto FF02::16 (All MLDv2 Routers)

• When a host no longer wants to receive traffic for a multicast group, it can inform the router by sending a Multicast Listener Done message.

4848

MLDv2 SnoopingMLD Querier


A

B

C


R1I will send packets for this

group out this interface.

I will also send packets for

this group out this interface.

• A switch can snoop Listener Reports from the hosts and creates an entry in its Layer 2 forwarding table for the port it was received.

• If another host sends a listener report for the same group, the switch snoops their reports and adds them to the existing Layer 2 forwarding table entry.

• With MLD snooping enabled, multicast messages for this group are only sent out ports with hosts that are members of that group.

• Remember, solicited node multicasts are forwarded out all ports because of the potentially huge forwarding tables needed to to store these addresses.

4949

For more on IPv6 Multicast

MLD Querier

A C

R1I will send packets for this

group out this interface.

I will also send packets for

this group out this interface.

• For more on Multicast and MLD see IPv6 Multicast Primer (PowerPoint PDF) by Tim Martin (CCIE #2020, Cisco Solutions Architect)


BListener Report Listener Report for groupFF3E:40:2001:DB8:CAFE:1:AAAA:AAAAto FF02::16 (All MLDv2 Routers)

5050

Path Path MTU MTU discoverydiscovery

�� IPv6 je napustio princip IPv6 je napustio princip fragmentacije paketa.fragmentacije paketa.

��Uvedena je obaveza korišćenja Uvedena je obaveza korišćenja path path MTU MTU discovery discovery mehanizma u cilju mehanizma u cilju MTU MTU discovery discovery mehanizma u cilju mehanizma u cilju odreñivanja najmanjeg MTU duž odreñivanja najmanjeg MTU duž putanje komunikacije.putanje komunikacije.

�� Inicijalni paket koji se šalje ima Inicijalni paket koji se šalje ima dužinu koja odgovara MTU vrednosti dužinu koja odgovara MTU vrednosti interfejsa preko koga se šalje.interfejsa preko koga se šalje.

5151

Path Path MTU MTU discoverydiscovery

�� Ukoliko paket naiñe na link čije je MTU Ukoliko paket naiñe na link čije je MTU manji, taj ruter šalje ICMPv6 poruku manji, taj ruter šalje ICMPv6 poruku ““Packet Too BigPacket Too Big” u okviru koje šalje i svoj ” u okviru koje šalje i svoj MTU. MTU.

�� Izvorni host šalje novi paket čija dužina Izvorni host šalje novi paket čija dužina odgovara MTU vrednosti koja je dobijena. odgovara MTU vrednosti koja je dobijena.

�� Proces se ponavlja dok paket ne stigne do Proces se ponavlja dok paket ne stigne do odredišnog hosta. odredišnog hosta.

�� Dobijeni MTU se pamti za navedenu Dobijeni MTU se pamti za navedenu sesiju.sesiju.

5252

Literatura:Literatura:

��http://www.cabrillo.edu/~rgraziani/ihttp://www.cabrillo.edu/~rgraziani/ipv6pv6--presentations.htmlpresentations.html

��http://www.ietf.org/http://www.ietf.org/

5353

IP IP versionversion 66

Dr Dr NenadNenad KrajnoviKrajnoviććee--mail: krajkomail: krajko@@etf.bg.acetf.bg.ac..rsrs

Documents

Dr Dr NenadNenadKrajnoviKrajnovićć ee--mail: krajkomail: …telekomunikacije.etf.bg.ac.rs/predmeti/ot4ai/IPv6-osnove.pdf · 2016-04-18 · Razlozi za uvođenje IPv6 Potrošen adresni