Ip4 And Ip6 Computer Science Essay

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This is the first version of IP to be mostly used worldwide. This internet protocol most of today's internet traffic. There are over 4 billion ipv4 addresses. That is a lot of IP addresses. It is not enough to last forever.


This is the new version of internet protocol provides a much more address pool then ipv4. This is deployed in 1999. This is meets the world's IP addressing requirements for future.

The major differences between IPv4 and IPv6

The main differences are number of IP addresses. There are 4,000,000,000 IP addresses in IPv4 and in IPv6 there are over 340,000,000,000,000,000,000,000, 000,000,000,000,000 addresses.

The IPv4 and IPv6 addresses are used in simultaneously in the internet.ip4ip6.bmp

IPv4 means Internet Protocol version 4, whereas IPv6 means Internet Protocol version 6.

IPv4 is 32 bits IP address that we use commonly; it can be, or other 32 bits IP addresses. IPv4 can support up to 232addresses, however the 32 bits IPv4 addresses are finishing to be used in near future, so IPv6 is developed as a replacement.

IPv6 is 128 bits, can support up to 2128 addresses to fulfill future needs with better security and network related features. Here are some examples of IPv6 address:




Description IPv4 IPv6

Address IP4

32 bits long (4 bytes). Address is composed of a network and a host portion, which depend on address class. Various address classes are defined: A, B, C, D, or E depending on initial few bits. The total number of IPv4 addresses is 4 294 967 296.

The text form of the IPv4 address is nnn.nnn.nnn.nnn, where 0<=nnn<=255, and each n is a decimal digit. Leading zeros can be omitted. Maximum number of print characters is 15, not counting a mask.


128 bits long (16 bytes). Basic architecture is 64 bits for the network number and 64 bits for the host number. Often, the host portion of an IPv6 address (or part of it) will be derived from a MAC address or other interface identifier.

Depending on the subnet prefix, IPv6 has a more complicated architecture than IPv4.

The number of IPv6 addresses is 1028 (79 228 162 514 264 337 593 543 950 336) times larger than the number of IPv4 addresses. The text form of the IPv6 address is xxxx: xxxx: xxxx:xxxx:xxxx:xxxx:xxxx:xxxx, where each x is a hexadecimal digit, representing 4 bits. Leading zeros can be omitted. The double colon (::) can be used once in the text form of an address, to designate any number of 0 bits. For example: ffff: is an IPv4-mapped IPv6 address.

Address allocation


Originally, addresses were allocated by network class. As address space is depleted, smaller allocations using Classless Inter-Domain Routing (CIDR) are made. Allocation has not been balanced among institutions and nations.


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 sub netting. The address space is large enough to give every person in the world their own /48 subnet prefix length.

Address lifetime

Generally, not an applicable concept, except for addresses assigned using DHCP.

IPv6 addresses have two lifetimes: preferred and valid, with the preferred lifetime always <= valid.

After the preferred lifetime expires, the address is not to be used as a source IP address for new connections if an equally good preferred address is available. After the valid lifetime expires, the address is not used (recognized) as a valid destination IP address for incoming packets or used as a source IP address.

Address mask

Used to designate network from host portion.

Not used (see address prefix).

Address prefix

Sometimes used to designate network from host portion. Sometimes written as /nn suffix on presentation form of address.

Used to designate the subnet prefix of an address. Written as /nnn (up to 3 decimal digits, 0 <= nnn <= 128) suffix after the print form. An example is fe80::982:2a5c/10, where the first 10 bits comprise the subnet prefix.

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.

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.

Address scope

For uncast addresses, the concept does not apply. There are designated private address ranges and loopback. Outside of that, addresses are assumed to be global.

Start of changeIn IPv6, address scope is part of the architecture. Unicast addresses have two defined scopes, including link-local and global; and multicast addresses have 14 scopes. Default address selection for both source and destination takes scope into account.

A scope zone is an instance of a scope in a particular network. As a consequence, IPv6 addresses sometimes must be entered or associated with a zone ID. The syntax is %zid where zid is a number (usually small) or a name. The zone ID is written after the address and before the prefix. For example, 2ba::1:2:14e:9a9b:c%3/48.

Address types

Unicast, multicast, and broadcast.

Unicast, multicast, and anycast. See IPv6 address types for descriptions.

Communications trace

A tool to collect a detailed trace of TCP/IP (and other) packets that enter and leave the system.

Same for IPv6, and IPv6 is supported.


You must configure a newly installed system before it can communicate with other systems; that is, IP addresses and routes must be assigned.

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 auto configuration. You can also manually configure the IPv6 interface. So, the system will be able to communicate with other IPv6 systems that are local and remote, depending on the type of network and whether an IPv6 router exists.

Domain Name System (DNS)

Applications accept host names and then use DNS to get an IP address, using socket API gethostbyname().Applications also accept IP addresses and then use DNS to get host names using gethostbyaddr().For IPv4, the domain for reverse lookups is in-addr.arpa.

Same for IPv6. Support for IPv6 exists using AAAA (quad A) record type and reverse lookup (IP-to-name). An application may elect to accept IPv6 addresses from DNS (or not) and then use IPv6 to communicate (or not).

The socket API gethostbyname() only supports IPv4. For IPv6, a new getaddrinfo() API is used to obtain (at application choice) IPv6 only, or IPv4 and IPv6 addresses.End of change

For IPv6, the domain used for reverse lookups is ip6.arpa, and if not found then ip6.int (see API getnameinfo()).

Dynamic Host Configuration Protocol (DHCP)

Used to dynamically obtain an IP address and other configuration information. i5/OS supports a DHCP server for IPv4.

The i5/OS implementation of DHCP does not support IPv6.

File Transfer Protocol (FTP)

File Transfer Protocol allows you to send and receive files across networks.

The i5/OS implementation of FTP does not support IPv6.


When a packet is too big for the next link over which it is to travel, it can be fragmented by the sender (host or router).

For IPv6, fragmentation can only occur at the source node, and reassembly is only done at the destination node. The fragmentation extension header is used.

Host table

On iSeries Navigator, a configurable table that associates an Internet address with a host name; for example,, loopback. This table is used by the sockets name resolver, either before a DNS lookup or after a DNS lookup fails (determined by host name search priority). Currently, this table does not support IPv6. Customers need to configure an AAAA record in a DNS for IPv6 domain resolution. You can run the DNS locally on the same system as the resolver, or you can run it on a different system.

Interface The conceptual or logical entity used by TCP/IP to send and receive packets and always closely associated with an IPv4 address, if not named with an IPv4 address. Sometimes referred to as a logical interface.

Can be started and stopped independently of each other and independently of TCP/IP using STRTCPIFC and ENDTCPIFC commands and using iSeries Navigator.

Same concept as IPv4.

Can be started and stopped independently of each other and independently of TCP/IP using iSeries Navigator only.

Internet Control Message Protocol (ICMP) ICMP is used by IPv4 to communicate network information. Used similarly for IPv6; however, Internet Control Message Protocol version 6 (ICMPv6) provides some new attributes.

Basic error types remain, such as destination unreachable, echo request and reply. New types and codes are added to support neighbor discovery and related functions.

Internet Group Management Protocol (IGMP)

IGMP is used by IPv4 routers to find hosts that want traffic for a particular multicast group, and used by IPv4 hosts to inform IPv4 routers of existing multicast group listeners (on the host).

Replaced by MLD (multicast listener discovery) protocol for IPv6. Does essentially what IGMP does for IPv4, but uses ICMPv6 by adding a few MLD-specific ICMPv6 type values.

IP header Variable length of 20-60 bytes, depending on IP options present. Fixed length of 40 bytes. There are no IP header options. Generally, the IPv6 header is simpler than the IPv4 header

IP header options Various options that might accompany an IP header (before any transport header). The IPv6 header has no options. Instead, IPv6 adds additional (optional) extension headers. The extension headers are AH and ESP (unchanged from IPv4), hop-by-hop, routing, fragment, and destination. Currently, IPv6 supports some extension headers.

IP header protocol byte The protocol code of the transport layer or packet payload; for example, ICMP. The type of header immediately following the IPv6 header. Uses the same values as the IPv4 protocol field. But the architectural effect is to allow a currently defined range of next headers, and is easily extended. The next header will be a transport header, an extension header, or ICMPv6..

P header Type of Service (TOS) byte Used by QoS and differentiated services to designate a traffic class. Designates the IPv6 traffic class, similarly to IPv4. Uses different codes. Currently, IPv6 does not support TOS.

iSeries Navigator support iSeries Navigator provides a complete configuration solution for TCP/IP. Same for IPv6. No CL commands are available for IPv6 configuration.

LAN connection

Used by an IP interface to get to the physical network. Many types exist; for example, token ring, and Ethernet. Sometimes referred to as the physical interface, link, or line.

IPv6 can be used with any Ethernet adapters and is also supported over virtual Ethernet between logical partitions.