IPv4 vs IPv6

Comparative Study of

IPv4 and IPv6 Network Protocol

M Tech ,WCE Sangli

Under Guidance of

Prof. S.P. Sonavane Mr. Anil Kumar Gupta WCE Sangli CDAC Pune

IP Protocol

● Primary network protocol used on the Internet

● Data on an Internet Protocol network is organized into

packets

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.,

IPv4 Delivery Model

● Best effort service

– Network will do its best to get packet to destination

● Does NOT guarantee:

– 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

Network Address Translation

B

C

IP Fragmentation

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

IP Packet _{2 1}

IP Packets Fragmentation

MTU

IP De-fragmentation

●

Internet layer process on destination host

defragments, restoring the original packet

●

IP Defragmentation only occurs once

Destination Host Internet Process De fragmentation Source Host Internet Process

IPv4 Limitation's

● Exhaustion of the IPv4 address space

● Simpler configuration

● Security at the Internet layer

IPv6 over IPv4

● Larger Address Space

● Efficient and Extensible IP datagram

● Efficient Route Computation and

● Aggregation

● Improved Host and Router Discovery

● New Stateless and State full Address

● Auto configuration

● Required Security for IP datagrams

IPv4 & IPv6 Header Comparison

Version IHL Type of Service Total Length

Identification Flags Fragment _Offset

Time to Live Protocol Header Checksum

Source Address Destination Address

Options Padding

Version Traffic Class Flow Label

Payload Length _HeaderNext Hop Limit

Source Address

Destination Address

IPv4 Header

IPv4 Header IPv6 HeaderHeader

- field’s name kept from IPv4 to IPv6 - fields not kept in IPv6

en

128-bit IPv6 Address

128-bit IPv6 Address

3FFE: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

Types of IPv6 Addresses

● 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

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

IPv6 Address Notation: Example

Neighbor Discovery (RFC 2461)

● Protocol built on top of ICMPv6 (RFC 2463)

Combination of IPv4 protocols (ARP, ICMP,…)

● Neighbor Discovery:

Determines the link-layer address of a neighbor on the same link, Duplicate Address Detection

Finds neighbor routers, Keeps track of neighbors

● Defines 5 ICMPv6 packet types

Router Solicitation / Router Advertisements

Neighbor Solicitation / Neighbor Advertisements Redirect

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

RA indicates SUBNET PREFIX

IPv6 Auto-Configuration

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

● StatefulStateful

DHCPv6 (under definition at IETF)

● RenumberingRenumbering

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 domain-interior routers to learn of prefix introduction / withdrawal

SUBNET PREFIX + MAC ADDRESS SUBNET PREFIX + MAC ADDRESS SUBNET PREFIX + MAC ADDRESS SUBNET PREFIX + MAC ADDRESS

Major Improvements of

IPv6 Header

●

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

:

Differences in IPv4 and IPv6

Feature IPv4 IPv6

Source and destination address

32 bits 128 bits

IPSec Optional required

Payload ID for QoS in the

header No identification Using Flow label field Fragmentation Both router and the

sending hosts

Only supported at the sending hosts

Header checksum included Not included

Resolve IP address to a link layer address

broadcast ARP request Multicast Neighbor Solicitation message

Determine the address of

the best default gateway Discovery(optional)ICMP Router ICMPv6 Router Solicitation and Router Advertisement (required)

Send traffic to all nodes on a subnet

Broadcast Link-local scope all-nodes multicast address

Challenges for IPv6

●

Deployment Cost

●

Security Issues

●

No Customer Demand

●

Lack of IPv6 security training/education