Table of Contents

IPV4 & IPV6

IPV4 Vs IPV6. Lets first study about what is internet Protocol (IP) ?

Internet Protocol

Internet Protocol is a set of technical rules that defines how computers communicate over a network. It is a network-layer protocol used to move information through a packet-switched network. An IP (Internet Protocol) address is a number that identifies a computer connected to the Internet. Every computer that is connected to the Internet must have unique IP address. There are currently two versions: IP version 4 (IPv4) and IP version 6 (IPv6).In IPv4, each section contains an 8-bit value represented as a number ranging from 0 to 255. This is also called 32-bit addressing. In this scheme, there are more than 4 billion possible IP addresses. However, the allocation of these IP addresses follows a two-level architecture that assigns IP numbers to a network and the hosts on that network. This architecture has proved to be an inefficient method for assigning IP address space and has led to the idea that the Internet will eventually “run out” of IP addresses. IPv6 will make use of 128-bit IP addresses. In this scheme, an IP address will consist of eight sections, each containing a 16-bit value.

IPv4 (internet protocol version 4):

IPv4 was the first version of Internet Protocol to be widely used, and accounts for most of today’s Internet traffic. There are just over 4 billion IPv4 addresses. It uses a 32 bit addressing and allows for 4,294,967,296 unique addresses. Depending upon segmentation IPv4 has four different class types, the class types are A, B, C, and D. The different segmentation for these addresses is shown below in Table 1.

The ipv4 uses a subnet mask because of the large numbers of computers used today. The subnet mask helps to reduce the number of unique IP given to companies, corporations and so on.

Some typical characteristics of IPv4 are given as:

Data-oriented protocol to be used on a packet switched internetwork.
It is a best effort delivery protocol in that it does not guarantee delivery, nor does it assure proper sequencing, or avoid duplicate delivery.
Addresses are denoted by 4 groups of octets separated by periods in between them.

Example: 132.170.215.150

IPv4 uses 32-bit (four-byte) addresses, which limits the address space to 4,294,967,296 (232) possible unique addresses.
As the number of addresses available are consumed, an IPv4 address shortage appears to be inevitable, however network address translation (NAT) has significantly delayed this inevitability.

IPv6 (internet protocol version 6):

IPv6 was designed by the Internet Engineering Task Force (IETF) to improve on the scalability, security, ease of configuration, and network management capabilities of IPv4. IPv6 will make use of 128-bit IP addresses. In this scheme, an IP address will consist of eight sections, each containing a 16-bit value. The number of IP addresses possible with this scheme is equal to the IPv4 address space squared, twice. The general syntax for the new IP addresses is to have the values of the IP address separated by colons. For example: 1080:0:0:0:8:800:200C:417A

IPv6 provides increased flexibility and connectivity for existing networked devices, addresses the limited address availability inherent in IPv4, and the infrastructure for the next wave of Internet devices, such as PDAs, mobile phones and appliances.

Typical characteristics of IPv6 are given below:

IPv6 or Internet Protocol Version 6 is the next generation protocol for the Internet.
IPv6 has a very large address space (128 bits).
Brings Quality of Service that is required for several new applications.
Guarantee performance while heavy traffic over network.
More efficient routing.
Reduced Management required.
Multi-Homing.

Typical characteristics of IPv6 are given below:

IPv6 or Internet Protocol Version 6 is the next generation protocol for the Internet.
IPv6 has a very large address space (128 bits).
Brings Quality of Service that is required for several new applications.
Guarantee performance while heavy traffic over network.
More efficient routing.
Reduced Management required.
Multi-Homing.

IPV4 Vs IPV6

IPV4

(Intermit Protocol Version 4)

IPV6

( Intermit Protocol Version 6)

Address

Source and destination addresses 32 bits long (4 bytes) address which is composed of a network and a host portion.

Address allocation:

Originally, addresses were allocated by network class. As address space is depleted, smaller allocations using Classless Inter-Domain Routing (CIDR) are made.

Address mask:

Here address mask is Used to designate network from host portion.

Address Resolution Protocol (ARP):

Address Resolution Protocol is used by IPv4 to find a physical address, such as the MAC or link address, associated with an IPv4 address.

Configuration:

You must configure a newly installed system through DHCP or manually

before it can communicate with other systems; that is, IP addresses and routes must be assigned.

IP header:

Variable length of 20-60 bytes, depending on IP options present.

Address types:

The Internet standards define the following types of IPv4 addresses:

Unicast: Assigned to a single network interface located on a specific subnet on the network and used for one-to-one communications.
Multicast: Assigned to one or more network interfaces located on various subnets on the network and used for one-to-many communications.
Broadcast: Assigned to all network interfaces located on a subnet on the network and used for one-to-everyone-on-a-subnet communications.

Security:

The security was not included in the original protocol itself

Identification of packet flow:

IPv4 header does not identify packet flow for QoS handling by routers.

Fragmentation of packets:

Both routers and the sending host fragment packets.

Cheksum:

Header includes a checksum.

Membership in local subnet groups:

Internet Group Management Protocol (IGMP) manages membership in local subnet groups.

Determination of IP address:

ICMP Router Discovery is used to determine the IPv4 address of the best default gateway, and it is optional.

Packet size:

Must support a 576-byte packet size (possibly fragmented).

Source and destination addresses are 128 bits long (16 bytes). Basic architecture is 64 bits for the

network number and 64 bits for the host number.

Allocation is in the earliest stages. The Internet Engineering Task Force (IETF) and Internet Architecture Board (IAB) have recommended that essentially every organization, home, or entity be allocated a /48 subnet prefix length. This would leave 16 bits for the organization to do subnetting.

No address mask is used.

IPv6 embeds these functions within IP itself as part of the algorithms for stateless autoconfiguration and neighbor discovery using Internet Control Message Protocol version 6(ICMPv6). Hence, there is no such thing as ARP6.

Configuration is optional, depending on functions required. IPv6 can be used with any Ethernet adapter and can be run over the loopback interface. IPv6 interfaces are self-configuring using IPv6 stateless (ICMPv6). Hence, there is no such thing as ARP6.

Fixed length of 40 bytes. There are no IP header options. Generally, the IPv6 header is simpler than the IPv4 header.

IPv6 addressing is classified into three categories:

Unicast address : an identifier for a single interface.

Multicast address: an identifier for a group/set of interfaces that may belong to the different nodes.

Anycast address : identifiers for a set of interfaces that may belong to the different nodes

In IPv6, the security is a part of the protocol itself. The security in IPv6 is ensured due to the 2 extension

IPv6 header contains Flow Label field, which identifies packet flow for QoS handling by router.

Only the sending host fragments packets; routers do not.

Header does not include a checksum.

Multicast Listener Discovery (MLD) messages manage membership in local subnet groups.

ICMPv6 Router Solicitation and Router Advertisement messages are used to determine the IP address of the best default gateway, and they are required.

Must support a 1280-byte packet size (without fragmentation).

IPV4 Vs IPV6 in term of standards

Conclusion:

The Internet is migrating from IPv4 to IPv6. Currently IPv6 network penetration is still low but it is expected to grow, while IPv4 address pool is projected by Regional Internet Registry to be exhausted by the end of 2011. The reason why uptake of IPv6 is still low is because of high cost of service migration from IPv4 to IPv6. Anyway, at the moment IPv6 is only used by universities and by isolated spots, because the internet is such a huge network, and it is very difficult to migrate it all, specially having into account that there are many operators of big networks that prefer to stay in the safe side, or what is the same, operating safely with IPv4: “never touch a running network”.