Topic of PresentationTopic of Presentation

IPv6IPv6Presented by: Mahwish ChaudharyPresented by: Mahwish Chaudhary

Roll No 08TL01Roll No 08TL01

ContentsContents

IP Network AddressingIP Network Addressing Historical aspects of IPv6Historical aspects of IPv6 Classful IP addressingClassful IP addressing Techniques to reduce address Techniques to reduce address

shortage in IPv4shortage in IPv4 Features of IPv6Features of IPv6 Header ComparisonsHeader Comparisons ConclusionsConclusions

IP Network AddressingIP Network Addressing

INTERNET INTERNET world’s largest public world’s largest public data network, doubling in size every nine data network, doubling in size every nine monthsmonths

IPv4, defines a 32-bit address - 2IPv4, defines a 32-bit address - 232 32

(4,294,967,296) (4,294,967,296) IPv4 addresses availableIPv4 addresses available The first problem is concerned with the The first problem is concerned with the

eventual depletion of the IP address eventual depletion of the IP address space. space.

Historical Aspects of IPv6Historical Aspects of IPv6

IPv4 address space not big enoughIPv4 address space not big enough Can’t get needed addresses Can’t get needed addresses

(particularly outside Americas)(particularly outside Americas) Routing table issuesRouting table issues

Competing plans to address problemCompeting plans to address problem Some 64-bit, some 128-bitSome 64-bit, some 128-bit

Current scheme unveiled at Toronto Current scheme unveiled at Toronto IETF (July 1994)IETF (July 1994)

Classful AddressingClassful Addressing

When IP was first standardized in Sep When IP was first standardized in Sep 1981, each system attached to the IP 1981, each system attached to the IP based Internet had to be assigned a based Internet had to be assigned a unique 32-bit addressunique 32-bit address

The 32-bit IP addressing scheme involves The 32-bit IP addressing scheme involves a two level addressing hierarchya two level addressing hierarchy

Network Number/PrefixNetwork Number/Prefix Host NumberHost Number

Classful Addressing…Classful Addressing…

Divided into 5 Divided into 5 classesclasses

Class A 8 bits N/W Class A 8 bits N/W id and 24 bits host id and 24 bits host id and so on B,C.id and so on B,C.

Wastage of IP Wastage of IP addresses by addresses by assigning blocks assigning blocks of addresses of addresses which fall along which fall along octet boundaries octet boundaries

Techniques to reduce Techniques to reduce address shortage in IPv4address shortage in IPv4

SubnettingSubnetting Classless Inter Domain Routing Classless Inter Domain Routing

(CIDR)(CIDR) Network Address Translation (NAT)Network Address Translation (NAT)

SubnettingSubnetting

Three-level hierarchy: network, subnet, Three-level hierarchy: network, subnet, and host.and host.

The extended-network-prefix is The extended-network-prefix is composed of the classful network-prefix composed of the classful network-prefix and the subnet-numberand the subnet-number

The extended-network-prefix has The extended-network-prefix has traditionally been identified by the traditionally been identified by the subnet masksubnet mask

Network-Prefix Subnet-Number Host-Number

Subnetting ExampleSubnetting Example

Internet G

H1 H2

H3 H4

Subnet mask 255.255.255.0

All trafficto 128.10.0.0

128.10.1.1 128.10.1.2

128.10.2.1 128.10.2.2

Sub-network 128.10.1.0

Sub-network 128.10.2.0

Net mask 255.255.0.0

Classless Inter-Domain Classless Inter-Domain RoutingRouting

Eliminates traditional classful IP Eliminates traditional classful IP routing.routing.

Supports the deployment of Supports the deployment of arbitrarily sized networks arbitrarily sized networks

Routing information is advertised Routing information is advertised with a bit mask/prefix lengthwith a bit mask/prefix length specifies the number of leftmost contiguous bits specifies the number of leftmost contiguous bits in the network portion of each routing table entryin the network portion of each routing table entry

Example: 192.168.0.0/21Example: 192.168.0.0/21

Network Address Network Address TranslationTranslation

Each Each organization- organization- single single IP IP addressaddress

Within Within organization – organization – each host with IP each host with IP unique to the unique to the orgn., from orgn., from reserved set of IP reserved set of IP addresses addresses

3 Reserved ranges3 Reserved ranges

10.0.0.0 – 10.255.255.255 (16,777,216 hosts)10.0.0.0 – 10.255.255.255 (16,777,216 hosts)

172.16.0.0 – 172.31.255.255/12 (1,048,576 172.16.0.0 – 172.31.255.255/12 (1,048,576 hosts)hosts)

192.168.0.0 – 192.168.255.255/16 (65,536 192.168.0.0 – 192.168.255.255/16 (65,536 hosts)hosts)

NAT ExampleNAT Example

SourceComputer

SourceComputer'sIP Address

SourceComputer's

Port

NAT Router'sIP Address

NAT Router'sAssigned

Port Number

A 10.0.0.1 400 24.2.249.4 1

B 10.0.0.2 50 24.2.249.4 2

C 10.0.0.3 3750 24.2.249.4 3

D 10.0.0.4 206 24.2.249.4 4

10.0.0.4

10.0.0.1

B

C

Features of IPv6Features of IPv6

Larger Address Space Aggregation-based address hierarchy

– Efficient backbone routing Efficient and Extensible IP datagram Security Mobility

128-bit IPv6 Address128-bit IPv6 Address3FFE:085B:1F1F:0000:0000:0000:00A9:1234

8 groups of 16-bit hexadecimal numbers separated by “:”

3FFE:85B:1F1F::A9:1234

:: = all zeros in one or more group of 16-bit hexadecimal numbers

Leading zeros can be removed

40bytes

20bytes

IPv4

IPv6

0 15 16 31

vers hlen TOS total length

identification flags flag-offset

TTL protocol header checksum

source address

destination address

options and padding

vers traffic class flow-label

payload length next header hop limit

source address

destination address

Removed (6)• ID, flags, flag offset• TOS, hlen• header checksum

Changed (3)

Added (2)

Expanded

• total length => payload• protocol => next header• TTL => hop limit

• traffic class• flow label

• address 32 to 128 bits

Header comparisonHeader comparison

Major Improvements of Major Improvements of IPv6 HeaderIPv6 Header

No option fieldNo option field: Replaced by : Replaced by extension header. Result in a fixed extension header. Result in a fixed length, 40-byte IP header.length, 40-byte IP header.

No header checksumNo header checksum: Result in fast : Result in fast processing. processing.

No fragmentation at intermediate No fragmentation at intermediate nodesnodes: Result in fast IP forwarding.: Result in fast IP forwarding.

Types of IPv6 AddressesTypes of IPv6 Addresses

Like IPv4…Like IPv4… UnicastUnicast

An identifier for a single interface. A packet sent to An identifier for a single interface. A packet sent to a unicast address is delivered to the interface a unicast address is delivered to the interface identified by that address.identified by that address.

MulticastMulticast An identifier for a set of interfaces (typically An identifier for a set of interfaces (typically

belonging to different nodes). A packet sent to a belonging to different nodes). A packet sent to a multicast address is delivered to all interfaces multicast address is delivered to all interfaces identified by that address.identified by that address.

Anycast: Anycast: An identifier for a set of interfaces (typically An identifier for a set of interfaces (typically

belonging to different nodes). A packet sent to an belonging to different nodes). A packet sent to an anycast address is delivered to one of the interfaces anycast address is delivered to one of the interfaces identified by that address (the "nearest" one, identified by that address (the "nearest" one, according to the routing protocols' measure of according to the routing protocols' measure of distance).distance).

Specified in the the v6 address architecture RFC.Specified in the the v6 address architecture RFC.

Conclusion

IPv6 is NEW …– built on the experiences learned from IPv4– new features– large address space– new efficient header– autoconfiguration

ReferencesReferences

IPng wg: http://playground.sun.com/pub/ipng/html

NGtrans: http://www.6bone.net/ngtrans IPv6 users site: http://www.ipv6.org IPv6 Forum: http://www.ipv6forum.com Normos (Internet standards):

http://www.normos.org