IPv4 vs IPv6

Comparative Study of IPv4 and IPv6 Network Protocol Mr. Sudhakar R. Mishra M Tech ,WCE Sangli Under Guidance of

Prof. S.P. Sonavane WCE Sangli

Mr. Anil Kumar Gupta CDAC Pune

IP Protocol ●

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Primary network protocol used on the Internet Data on an Internet Protocol network is organized into packets Functions at layer 3 of the OSI model

IPv4 Overview ●

32 bit Addressing scheme – Host address, e.g., 192.168.1.1 – Network address, e.g., 192.168.1.0/24 or 192.168.1.0 255.255.255.0 – Host address is the first address in subnetwork, e.g. 192.168.1.0 – Broadcast address is the last address in the subnetwork, e.g., 192.168.1.255

IPv4 Delivery Model ●

Best effort service –

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Does NOT guarantee: – – – –

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Network will do its best to get packet to destination Any maximum latency or even ultimate success Sender will be informed if packet doesn’t make it Packets will arrive in same order sent Just one copy of packet will arrive

Implications – –

Scales very well Higher level protocols must make up for shortcomings ●

–

Reliably delivering ordered sequence of bytes  TCP

Some services not feasible ●

Latency or bandwidth guarantees

Network Address Translation ●

To prevent the fast depletion of IPv4 addresses

C

10.0.0.4

B

10.0.0.1 Source Computer

Source Computer's IP Address

Source Computer's Port

NAT Router's IP Address

NAT Router's Assigned 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

IP Fragmentation ●

If IP packet is longer than the MTU, the router breaks packet into smaller packets – – –

Called IP fragments Fragments are still IP packets Earlier in Mod A, fragmentation in TCP MTU IP Packet

3 Fragmentation

2 IP Packets

1

IP De-fragmentation ●

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Internet layer process on destination host defragments, restoring the original packet IP Defragmentation only occurs once Source Host Internet Process

Destination Host Internet Process

De fragmentation

IPv4 Limitation's ●

Exhaustion of the IPv4 address space

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Simpler configuration

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Security at the Internet layer

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Difficult to add support for future needs

IPv6 over IPv4 ●

Larger Address Space

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Efficient and Extensible IP datagram

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Efficient Route Computation and

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Aggregation

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Improved Host and Router Discovery

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New Stateless and State full Address

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Auto configuration

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Required Security for IP datagrams

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Easy renumbering

IPv4 & IPv6 Header Comparison IPv6 Header

IPv4 Header Version

IHL

Type of Service

Identification

Total Length

Flags

Version

Traffic Class

Fragment Offset Payload Length

Time to Live

Protocol

Hop Limit

Source Address

Destination Address Options

Legend

Next Header

Header Checksum

Source Address

Padding

- field’s name kept from IPv4 to IPv6 - fields not kept in IPv6 - Name & position changed in IPv6 - New field in IPv6

Flow Label

Destination Address

128-bit IPv6 Address 3FFE:085B:1F1F:0000:0000:0000:00A9:1234

8 groups of 16-bit hexadecimal numbers separated by “:” Leading zeros can be removed

3FFE:85B:1F1F::A9:1234 :: = all zeros in one or more group of 16-bit hexadecimal numbers

Types of IPv6 Addresses ●

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●

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Unicast –

Address of a single interface

–

Delivery to single interface

Multicast –

Address of a set of interfaces

–

Delivery to all interfaces in the set

Anycast –

Address of a set of interfaces

–

Delivery to a single interface in the set

No more broadcast addresses

IPv6 Addressing Rules ●

● ●

128 bits (or 16 bytes) long: four times as long as its predecessor. 2128 : about 340 billion billion billion billion different addresses Colon hexadecimal notation:

●

– – –

addresses are written using 32 hexadecimal digits. digits are arranged into 8 groups of four to improve the readability. Groups are separated by colons

2001:0718:1c01:0016:020d:56ff:fe77:52a3

IPv6 Address Notation: Example 128.91.45.157.220.40.0.0.0.0.252.87.212.200.31.255

Neighbor Discovery (RFC 2461) ●

Protocol built on top of ICMPv6 (RFC 2463) Combination of IPv4 protocols (ARP, ICMP,…)

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Neighbor Discovery: Determines the link-layer address of a neighbor on the same link, Duplicate Address Detection Finds neighbor routers, Keeps track of neighbors

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Defines 5 ICMPv6 packet types Router Solicitation / Router Advertisements Neighbor Solicitation / Neighbor Advertisements Redirect

IPv6 Auto-Configuration ●

Stateless (RFC2462) Host autonomously configures its own Link-Local address Router solicitation are sent by booting nodes to request RAs for configuring the interfaces.

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RA indicates SUBNET PREFIX

SUBNET PREFIX + MAC ADDRESS

Stateful DHCPv6 (under definition at IETF)

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Renumbering Hosts renumbering is done by modifying the RA to announce the old prefix with a short lifetime and the new prefix. Router renumbering protocol (RFC 2894), to allow domaininterior routers to learn of prefix introduction / withdrawal

SUBNET PREFIX + MAC ADDRESS

At boot time, an IPv6 host build a Link-Local address, then its global IPv6 address(es) from RA

Major Improvements of IPv6 Header ●

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No option field: Replaced by extension header. Result in a fixed length, 40-byte IP header. No header checksum: Result in fast processing. No fragmentation at intermediate nodes: Result in fast IP forwarding.

Differences in IPv4 and IPv6 Feature Source and destination address IPSec Payload ID for QoS in the header Fragmentation Header checksum Resolve IP address to a link layer address Determine the address of the best default gateway Send traffic to all nodes on a subnet Configure address Manage local subnet group membership

IPv4

IPv6

32 bits

128 bits

Optional

required

No identification

Using Flow label field

Both router and the sending hosts

Only supported at the sending hosts

included

Not included

broadcast ARP request

Multicast Neighbor Solicitation message

ICMP Router Discovery(optional)

ICMPv6 Router Solicitation and Router Advertisement (required)

Broadcast

Link-local scope all-nodes multicast address

Manually or DHCP

Autoconfiguration

(IGMP)

Multicast Listener Discovery (MLD)

Challenges for IPv6 ●

Deployment Cost

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Security Issues

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No Customer Demand

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Lack of IPv6 security training/education

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Bugs in new code