1 Introduction An evolution of IPv4. Builds on IPv4. Most notable change is address changes to 128 bits. Dynamic environment. Requires a much more sophisticated

11

IntroductionIntroduction

An evolution of IPv4.

Builds on IPv4.

Most notable change is address changes to 128 bits.

Dynamic environment.

Requires a much more sophisticated operating environment.

Over 58 other protocols have changed with it.

Will run as islands using IPv4 as the backbone.

Cannot simply “flip a switch” to convert.

22

IPv6 (continued)IPv6 (continued)

IPv5 exists and is known as the Streams 2 (ST2) Protocol: RFC 1819 Operates at the same layer as IP Developed as an IP layer for real-time applications Includes QoS capabilities

IPv6 truly works on the finer aspects of IPv4.

Requires a dynamic environment: Many discovery options including:

Autoconfiguration Finding the maximum path MTU Finding other workstations without ARP Finding routers

33

IPv6 FeaturesIPv6 Features

Extended addressing capabilities.

Header format simplification.

Improved support for extensions and options.

Flow label capability.

Authentication and privacy capabilities.

IPv6 routing similar to IPv4 routing using CIDR.

OSPF, RIP, IDRP, and IS-IS can be used with minor modifications

44

From IPv4 to IPv6From IPv4 to IPv6

Built up to the IPv6 specification that we have today using various proposal submissions such as:

ISO CLNP– demonstrated as TUBA (TCP and UDP over Bigger Addresses)

IP version 7 (aka TP/IX, RFC 1475) IP in IP – evolved to IP address

encapsulation PIP – merged into SIP creating SIPP

(RFC 1710)

55

IP Version Numbers According to IP Version Numbers According to RFC 1700RFC 1700

DecimalDecimal KeywordKeyword VersionVersion ReferencesReferences

0 Reserved

1 - 3 Unassigned

4 IP Internet Protocol RFC 791

5 ST ST Datagram Mode RFC 1190, JWF

6 IPv6 RFC 1883

7 TP/IX TP/IX: The Next Internet

8 PIP The P Internet Protocol

9 TUBA TCP and UDP over Bigger Addresses

10 - 14 Unassigned

15 Reserved

66

IPv6 HeaderIPv6 Header

DADA SASATypeType86DD86DD IP Header and DataIP Header and Data CRCCRC

Ethernet Data FieldEthernet Data Field

VersVers PriorityPriority Total lengthTotal length

Payload lengthPayload length Next headerNext header Hop limitHop limit

Source IP addressSource IP address

Destination IP addressDestination IP address

IP datagram data (up to 65535 bytes)IP datagram data (up to 65535 bytes)

Next header– Could be transport layer headerNext header– Could be transport layer headeror an IPv6 extension headeror an IPv6 extension header

77

IPv4 Options Review – A ReviewIPv4 Options Review – A Review

Security

Loose source routing

Strict source routing

Record route

Stream ID

Internet timestamp

88

IPv4 and IPv6 Header DifferencesIPv4 and IPv6 Header Differences

IPv6 header is a static 40 bytes in length.

Total length field is replaced with payload length.

IPv6 allows for jumbograms (larger than 64k).

Extension headers.

TTL field is replaced with the hop limit.

Many Ipv4 options were moved to independent protocols.

99

IPv6 Header FormatIPv6 Header Format

DADA SASA IPv6 headerIPv6 header IP DataIP Data CRCCRC

IPv6 headerIPv6 header

Next header = 17Next header = 17 UDP header and dataUDP header and data

(UDP)(UDP)

TFTF

1010

FragmentationFragmentation

IPv6 headerIPv6 headerNext header = Next header =

routingrouting

DADA SASA IPv6 headerIPv6 header IP dataIP data CRCCRCTFTF

Routing header Next Routing header Next header = fragmentheader = fragment

Fragment header Fragment header Next header = UDPNext header = UDP

Fragment of UDPFragment of UDP

Header and dataHeader and data

1111

Priority and Flow LabelPriority and Flow Label

Still under much study.

Priority field distinguishes the datagram amongst other datagrams.

Two types of controlled traffic: Congestion Noncongestion

Flow labels allow the router to indentify a flow and place this label in the routing table for quick lookup.

1212

IPv6 AddressingIPv6 Addressing

Unicast Unicast – identifies a single interface.

AnyCastAnyCast – new for IPv6, it identifies a set of interfaces usually belonging to different nodes. Used to deliver datagrams to the “nearest” of the interfaces.

MulticastMulticast – an identifier belong to a group of interfaces. IPv6 extensively uses the multicast interface.

There is no broadcast address in IPv6.

1313

IPv6 Addressing (cont.)IPv6 Addressing (cont.)

Which provides for: 340,282,366,920,938,463,463,374,607,431,768,211,456 addresses

Address is written in hex.

Takes the form of: xxxx : xxxx : xxxx : xxxx : xxxx : xxxx : xxxx : xxxx FEDC:BA98:7654:3210:FEDC:BA98:7654:0321

Zeros can be truncated: FF:0000:0000:0000:0000:9085:9043:1234

FF::9085:9043:1234 Only one set of zeros can be truncated

128 bits

32 bits IPv4

1414

IPv6 Addressing (continued)IPv6 Addressing (continued)

The first few bits are indicators (as shown in a moment).

They do not register as a Class of address as in IPv4

Similar to CIDR, prefixes are used to indicate the routing.

Special addresses are reserved: Unspecified address Loopback address Embedded IPv4 address Multicast address

1515

IPv6 Addressing Prefix IPv6 Addressing Prefix Allocation Prefix (binary) Fraction of Address Space

ReservedUnassignedReserved for NSAPAllocationReserved for IPXAllocationUnassignedUnassignedUnassignedUnassigned

Provider-basedUnicast addressUnassignedReserved for geographic-based unicast addressesUnassignedUnassignedUnassignedUnassignedUnassignedUnassignedUnassigned

Link local useAddressesSite Local Use Addresses 1111 1110 11Muclticast Addresses

0000 00000000 0001

0000 001

0000 0100000 0110000 100001001

0100111001011101110111101111 101111 1101111 11100

1111 1110 101/10241111 1111

1/2561/256

1/128

1/1281/321/161/8

1/81/81/81/81/81/161/321/641/1281/512

1/1024

1/256

1616

6Bone Test Addressing6Bone Test Addressing

010010 Registry IDRegistry ID Provider IDProvider ID Subscriber IDSubscriber ID Subnet IDSubnet ID Interface IDInterface ID

010010 1111111111 AS numberAS number ResvResv IPv4 Network addressIPv4 Network address ResvResv Subnet IDSubnet ID Interface IDInterface ID

3 bits3 bits n bitsn bits m bitsm bits o bitso bits p bitsp bits 128-mnop bits128-mnop bits

3 bits3 bits 5 bits5 bits 8 bits8 bits 24 bits24 bits 8 bits8 bits 48 bits48 bits16 bits16 bits 16bits16bits

(IANA)(IANA)

1717

Provider-Based IPv6 AddressingProvider-Based IPv6 Addressing


3 bits3 bits n bitsn bits m bitsm bits o bitso bits p bitsp bits 128-mnop bits128-mnop bits

Provider-basedProvider-based

1818

11111110101111111010 00 Interface IDInterface ID

10 bits10 bits n bitsn bits 128 - n bits128 - n bits

usually the 48 bit IEEE addressusually the 48 bit IEEE address

0 . . . . . . . . . . . .0 . . . . . . . . . . . .

11111110111111111011 Interface IDInterface ID

10 bits10 bits n bitsn bits 128 - m - n bits128 - m - n bits

usually the 48 bit IEEE addressusually the 48 bit IEEE address

00 subnet IDsubnet ID

m bitsm bits

FE80FE80

FEC0FEC0

Local-Use IPv6 AddressingLocal-Use IPv6 Addressing

1919

IPv6 Addresses with Embedded IPv4 IPv6 Addresses with Embedded IPv4 AddressesAddresses

0000 . . . . . . . . . . . . . 0000 . . . . . . . . . . . . . 00000000

00000000 IPv4 32-bit addressIPv4 32-bit address

IPv4-compatible IPv6 addressIPv4-compatible IPv6 address

0:0:IPv4 address0:0:IPv4 address

96 bits96 bits 4 bits 4 bits 32 bits32 bits

2020

Unicast AddressesUnicast Addresses

Global provider based Geographic based NSAP IPX Hierarchical

Unspecified - 0:0 Site-local use Link-local use IPv4-capable host Loopback - 0:0:0:0:0:0:0:1

Provider based

Special use address


3 bits3 bits n bitsn bits m bitsm bits o bitso bits p bitsp bits 128-mnop bits128-mnop bitsProvider basedProvider based

Subscriber prefixSubscriber prefix area IDarea ID subnet IDsubnet ID interface ID interface ID

(possibly IEEE 802.x MAC address)(possibly IEEE 802.x MAC address)Generic structure of an IPv6 address Generic structure of an IPv6 address

2121

AutoconfigurationAutoconfiguration

Stateless Autoconfiguration. Initializing hosts join the all nodes multicast

address of FE02::1

Stateless autoconfiguration allows for a node to start up using the link-local prefix and some sort of token.

This will probably be the 48-bit Ethernet address

Address would be FE80::48-bit address (multicast)

Hosts send a solicitation message to all-routers using the all-routers multicast address of FF02::2.

Used to determine the node’s routing prefix and other routing parameters

Stateful autoconfiguration uses.

2222

Neighbor DiscoveryNeighbor Discovery

RFC 1970.

Very extensive and best to read RFC.

Nodes used Neighbor Discovery to determine link-layer addresses for neighbors.

Finds link-local hosts and routers.

Detects which neighbors are reachable and to detect link layer address changes.

ARP is not used with IPv6. This is the robust replacement for ARP

(IPv4)

2323

Neighbor Discovery (continued)Neighbor Discovery (continued)

In IPv6, Discovery messages use the various multicast address assignments for router discovery, neighbor discovery, etc.

The media (MAC) address is a multicast address as well:

33-33-last 32 bits of the IPv6 address

RFC 1970 applies to all link-layer types except NBMA and various proprietary interfaces.

2424

Neighbor Discovery TypesNeighbor Discovery Types

Router Discovery

Prefix Discovery

Parameter Discovery

Address Autoconfiguration

Address Resolution

Next-Hop determination

Neighbor Unreachability Detection

Duplicate Address Detection

Redirect

2525

Neighbor Discovery and IPv4Neighbor Discovery and IPv4

IPv6 Neighbor Discovery combines IPv4 protocols of ARP, ICMP Router Discovery, and ICMP Redirect.

IPv4 has no agreed-upon method for Dead Gateway Detection and Neighbor Unreachability detection.

2626

Neighbor Discovery and IPv4 Neighbor Discovery and IPv4 (continued)(continued)

IPv6 assumes a redirect next hop is on-link – on the same link that it resides.

IPv6 detects half link failures (neighbors that are suspect or that have gone away).

IPv6 Router advertisements do not contain a Preference field.

Using link-local addresses to identify routers means that this relationship is maintained even if the provider address changes.

Address resolution is accomplished at the ICMP layer.

2727

Address ResolutionAddress Resolution Purpose is to determine the link

level-address of a destination given only its IP address.

Consists of sending a Neighbor Solicitation message and waiting for a reply.

All nodes start up by joining the all-nodes multicast address and the solicited node multicast address

Solicited node address is taking the 96 bit prefix FF02:0:0:0:0:1 and place the low order 32 bits of the destination IP address to this

This allows for a range of FF02:1:0:0 through FF02:1:FFFF:FFFF

The full target address is embedded in the ICMP packet

2828

Methods of Deploying IPv6Methods of Deploying IPv6

Dual IP layer–a node that is running both the IPv4 and IPv6 TCP/IP protocol stacks.

IPv6 over IPv4 Tunnel–the process of taking an IPv6 datagram and wrapping an IPv4 header on it for transit across IPv4 routers.

Configured Tunnel–IPv4 tunnel endpoint address is determined by the encapsulating node

Automatic Tunnel–IPv4 tunnel endpoint is determined from the IPv4 address of the IPv6 packet

Transition consists of: IPv4-only node.

2929

IPv6 Tunneling IntroductionIPv6 Tunneling Introduction

Host to Router

Router to Router

Router To Host

Host to Host

3030

IPv6 Tunnel AddressingIPv6 Tunnel Addressing

IPv6 HeaderIPv6 HeaderTransport LayerTransport Layer

HeaderHeader DataData

IPv4 HeaderIPv4 Header IPv6 HeaderIPv6 Header Transport LayerTransport Layerheaderheader

DataData

::132.1.1.1::132.1.1.1

3131

IPv6 and IPv4 Dual-Stack StrategyIPv6 and IPv4 Dual-Stack Strategy

Medium Dependent media typeMedium Dependent media type

ApplicationsApplications

IPv4IPv4 IPv6IPv6

TCP/UDPTCP/UDP

Ethernet, Token Ring, FDDIEthernet, Token Ring, FDDI

3232

IPv6 TunnelingIPv6 Tunneling

IPv6IPv6hosthost

IPv4IPv4hosthost

IPv4/v6IPv4/v6routerrouter

Uh-Oh!Uh-Oh!

IPv6IPv6hosthost

Could be the InternetCould be the InternetIPv4 CloudIPv4 Cloud

IPv4/v6IPv4/v6routerrouter

IPv4IPv4routerrouter

IPv4IPv4hosthost

IPv6IPv6hosthost

IPv4/6IPv4/6hosthost

IPv4IPv4hosthost


3333

IPv6 TunnelingIPv6 Tunneling

IPv6/IPv4IPv6/IPv4routerrouter

IPv4 NetworkIPv4 Network









routerrouter

totorouterrouter


host tohost torouterroutertunneltunnel

host tohost to

hosthost

routerrouter

totohosthost

Host IPv6/IPv4Host IPv6/IPv4

IPv6/IPv4 hostIPv6/IPv4 host

Four possible ways to tunnelFour possible ways to tunnel

(last segment of (last segment of end-to-end span)end-to-end span)

3434

IPv6 Tunneling Flowchart 1IPv6 Tunneling Flowchart 1

YesYes

NoNo

NoNo

YesYes

Send direct to IPv6 routerSend direct to IPv6 routerwith destinationwith destination

address set to IPv6 formataddress set to IPv6 format

NoNo

Send IPv6 encapsulatedSend IPv6 encapsulated packet to IPv4 router; IPv6 destinationpacket to IPv4 router; IPv6 destination

addresses to the end node; IPv4addresses to the end node; IPv4address set to low-order 32 bitsaddress set to low-order 32 bits

of end nodeof end node

YesYes

End nodeEnd nodeaddress isaddress is

IPv4-compatibleIPv4-compatibleIPv6 addressIPv6 address

DestinationDestinationlocal?local?

IPv4 routerIPv4 routeravailable?available?

Send direct withSend direct withdestination addressdestination addressset to IPv6 fromatset to IPv6 fromat


DestinationDestinationunreachableunreachable

3535


YesYes

NoNo

NoNo

YesYes

Send direct to IPv6 routerSend direct to IPv6 routerwith IP destinationwith IP destination

set to final destinationset to final destinationin IPv6 formatin IPv6 format

NoNo

Send IPv6 datagram encapsulated inSend IPv6 datagram encapsulated inIPv4 packet. IPv6 destination addressIPv4 packet. IPv6 destination address

and IPv4 destination address is theand IPv4 destination address is theconfigured IPv4 address of theconfigured IPv4 address of the

tunnel endpoint.tunnel endpoint.

YesYes

End nodeEnd nodeaddress isaddress isIPv6-onlyIPv6-onlyaddressaddress



Send direct withSend direct withdestination addressdestination addressset to IPv6 fromatset to IPv6 fromat

Configured tunnelConfigured tunneland IPv4 routerand IPv4 router

available?available?


3636


YesYes

NoNo

NoNo

YesYes

Send IPv4 packet;Send IPv4 packet;destination address set todestination address set to

the IPv4 address of thethe IPv4 address of theend nodeend node

End nodeEnd nodeaddress isaddress is

IPv4IPv4



Send direct withSend direct withdestination addressdestination address

set to IPv4set to IPv4


3737

Anycast AddressingAnycast Addressing

Similar to a multicast address.

Address is sent to a group address (anycast) but the router delivers the datagram to the nearest member of the group.

Provides for applications such as file and print servers, time servers, name servers, DHCP, etc.

Similar to the NetWare protocol of “Get Nearest Server” request.

3838

Multicasting for IPv6Multicasting for IPv6

1111 11111111 1111 FlagsFlags ScopeScope Group IDGroup ID

8 bits8 bits 4 bits4 bits 4 bits4 bits 112 bits112 bits

00 00 00 TT Flag bitsFlag bitsT = Transient - 0 indicates IANA multicast assignedT = Transient - 0 indicates IANA multicast assigned

First part of the address is the multicast reserved bits FF.

The scope is included in the overall reserved address. For example, you could look for all name servers within a site local scope All name servers within a link local scope Same multicast function but different address Same function as the TTL in MBONE

3939

IPv6 RoutingIPv6 Routing

Existing routing protocols (OSPF, RIP, IDRD, etc.) are straightforward extensions of IPv4 routing.

IPv6 includes new routing extensions such as:

Provider selection Host mobility Auto-readdressing

OSPF: Creates a separate link state database Makes room for the 128 bit address Cannot interoperate with IPv4

4040

RIPngRIPng

CommandCommand VersionVersion Must be zeroMust be zero

IPv6 Address (128 bits)IPv6 Address (128 bits)

Route tagRoute tag Subnet maskSubnet mask MetricMetric

00 31318 bits8 bits 8 bits8 bits 16 bits16 bits

Variable in length and therefore number Variable in length and therefore number of entries per packet.of entries per packet.

more IPv6 addresses and metricsmore IPv6 addresses and metrics

more IPv6 addresses and metricsmore IPv6 addresses and metricsmore IPv6 addresses and metricsmore IPv6 addresses and metrics

4141

ICMPICMP

Found in RFC 1885 and originally found in RFC 792.

The functions of ICMP are explained in 1885, but many other RFCs are referenced:

1970 for Neighbor Discovery 1191 for Path MTU Discovery

IPv4 extension.

Continues to provide some maintenance for an unreliable IPv6.

No ICMPv6 messages are sent for ICMPv6 errors.

4242

TypeType ChecksumChecksum

Message body based on Type andMessage body based on Type andCode fields (variable length)Code fields (variable length)

ICMPv6 EncapsulationICMPv6 Encapsulation

DADA SASA TFTF CRCCRCIP dataIP data

IPv6 headerIPv6 headerNext header = 56Next header = 56

ICMP messageICMP message

IPv6 headerIPv6 header

CodeCode

4343

ICMPv6 and ICMPv4ICMPv6 and ICMPv4

Cleaned up ICMPv4. Timestamp, source quench, and information

request and reply were deleted (picked up by other protocols)

Eliminated unused codes and types.

IGMP is moved into ICMPv6. ICMPv6 is not compatible with ICMPv4;

however, it is the same format

ICMPv6 does copy more of the offending datagram when sending an error message.

Error messages have types from 0 - 127 and informational messages have types from 128 - 255.

4444

ICMPv6 Error MessagesICMPv6 Error Messages

Destination Unreachable: No route to destination Communication with destination

administratively prohibited Not a neighbor Address Unreachable Port Unreachable

Packet Too Big: Returns the largest packet size available

for the forwarded port

4545

ICMPv6 Error Messages (continued)ICMPv6 Error Messages (continued)

Time Exceeded Message. Hop limit exceeded in transit fragment reassembly time exceeded

Parameter Problem. Erroneous header field encountered Unrecognized nest header type

encountered Unrecognized IPv6 option

4646

ICMP Informational MessagesICMP Informational Messages

Echo Request

Echo Reply

Good ol’ PING

4747

ICMP and Neighbor DiscoveryICMP and Neighbor Discovery

Router Solicitation

Router Advertisement

Neighbor Solicitation

Neighbor Advertisement

Redirect

4848

ICMPv6 and MulticastICMPv6 and Multicast

Group Membership messages Group Membership Query Group Membership Report Group Membership Reduction

(Leave Group)

4949

IPv6 Cache EntriesIPv6 Cache Entries

Destination cache–contains link layer information about destinations to which data has been recently sent.

Neighbor cache–contains link layer information about a neighbor.

Prefix List cache–created from router advertisements, this is a listing of local prefixes.

Router List cache–contains information about those routers to which packets may be sent.

5050

IPv6 AlgorithmIPv6 Algorithm Easier if you understand RFC 1970.

To transmit a datagram, the source must consult the destination cache, prefix list, and the default router.

It needs to determine the “next-hop”

A source first looks in the destination cache for a matching entry to the destination IP address.

If one is not found here, consult the prefix list cache

Local address, the next hop is simply that of the destination IP address

5151

RFCs Related to IPv6RFCs Related to IPv6 1883: Describes the IPv6 protocol (RFC 2147 updates [does not replace] RFC 1883). 2147 PS: D. Borman, “TCP and UDP over IPv6 Jumbograms,” 05/23/97, (3 pages) (.txt format) (updates RFC 1883). 2133 I: R. Gilligan, S. Thomson, J. Bound, W. Stevens, “Basic Socket Interface Extensions for IPv6,” 04/21/97 (32

pages). 2080 PS: G. Malkin, R. Minnear, “RIPng for IPv6,” 01/10/97 (19 pages). 2073 PS: Y. Rekhter, P. Lothberg, R. Hinden, S. Deering, J. Postel, “An IPv6 Provider-Based Unicast Address

Format,” 01/08/97 (7 pages).

2030 I: D. Mills, “Simple Network Time Protocol (SNTP) Version 4 for IPv4, IPv6, and OSI,” 10/30/96 (18 pages). 2019 PS: M. Crawford, “Transmission of IPv6 Packets Over FDDI,” 10/17/96 (6 pages). 1972 PS: M. Crawford, “A Method for the Transmission of IPv6 Packets Over Ethernet Networks,” 08/16/96 (4

pages). 1971 PS: S. Thomson, T. Narten, “IPv6 Stateless Address Autoconfiguration,” 08/16/96 (23 pages). 1970 PS: T. Narten, E. Nordmark, W. Simpson, “Neighbor Discovery for IP Version 6 (IPv6),” 08/16/96 (82 pages). 1933 PS: R. Gilligan, E. Nordmark, “Transition Mechanisms for IPv6 Hosts and Routers,” 04/08/96 (22 pages). 1924 I: R. Elz, “A Compact Representation of IPv6 Addresses,” 04/01/96 (6 pages). 1897 E: R. Hinden, J. Postel, “IPv6 Testing Address Allocation,” 01/25/96 (4 pages). 1888 E: J. Bound, B. Carpenter, D. Harrington, J. Houldsworth, A. Lloyd, “OSI NSAPs and IPv6,” 08/16/96 (16

pages). 1887 I: Y. Rekhter, T. Li, “An Architecture for IPv6 Unicast Address Allocation,” 01/04/96 (25 pages). 1885 PS: A. Conta, S. Deering, “Internet Control Message Protocol (ICMPv6) for the Internet Protocol Version 6

(IPv6),” 01/04/96 (20 pages). 1884 PS: R. Hinden, S. Deering, “IP Version 6 Addressing Architecture,” 01/04/96 (18 pages) (.txt format). 1883 PS: S. Deering, R. Hinden, “Internet Protocol, Version 6 (IPv6) Specification,” 01/04/96 (37 pages) (updated by

RFC 2147). 1881 I: I. IESG, “IPv6 Address Allocation Management,” 12/26/95 (2 pages). 1809 I: C. Partridge, “Using the Flow Label Field in IPv6,” 06/14/95 (6 pages).

Documents

1 Introduction An evolution of IPv4. Builds on IPv4. Most notable change is address changes to 128 bits. Dynamic environment. Requires a much more sophisticated