IPv4 is currently the dominant Internet Protocol version, and was the first to receive widespread use.
The Internet Engineering Task Force (IETF) has designated IPv6 as the successor to version 4 for general use on the Internet. It significantly increases the size of the address space used to identify communication endpoints in the Internet, thereby allowing it to continue its tremendous growth rate.
IPv6 is also said to be IPng (IP Next Generation).
Limitations in IPv4:
Up to now we are using IPv4.IPv4 was remarkably but in spite of that it is beginning to have problems. Most importantly, there is a growing shortage of IPv4 addresses, which are needed by all new machines added to the Internet.
The limited address range forces organizations to use Network Address Translation (NAT) firewalls to map multiple private addresses to a single public IP address.NATs does not support standards-based network-layer security and also creates complicated barriers to VoIP, and other services.
Security was also an issue for IPv4. Although there are lots of ways of encrypting IPv4 traffic, such as using the IPSec protocol, but unfortunately all of the IPv4 encryption methods are proprietary and no real standard encryption methods exist.
IPv6 Features:
The IPv6 header has a new header format that is designed to minimize header overhead. This optimization is achieved by moving both non-essential fields and optional fields to extension headers that appear after the IPv6 header. Intermediate routes can process the streamlined IPv6 header more efficiently. IPv4 headers and IPv6 headers do not interoperate. IPv6 is not a superset of functionality, that is backward compatible with IPv4 is not possible. A host or router must use an implementation of both IPv4 and IPv6 to recognize and process both header formats. The IPv6 header is only twice as large as the IPv4 header, even though IPv6 addresses are four times as large as IPv4 addresses.
IPv4
IPv6 is also said to be IPng (IP Next Generation).
Limitations in IPv4:
Up to now we are using IPv4.IPv4 was remarkably but in spite of that it is beginning to have problems. Most importantly, there is a growing shortage of IPv4 addresses, which are needed by all new machines added to the Internet.
The limited address range forces organizations to use Network Address Translation (NAT) firewalls to map multiple private addresses to a single public IP address.NATs does not support standards-based network-layer security and also creates complicated barriers to VoIP, and other services.
Security was also an issue for IPv4. Although there are lots of ways of encrypting IPv4 traffic, such as using the IPSec protocol, but unfortunately all of the IPv4 encryption methods are proprietary and no real standard encryption methods exist.
IPv6 Features:
The IPv6 header has a new header format that is designed to minimize header overhead. This optimization is achieved by moving both non-essential fields and optional fields to extension headers that appear after the IPv6 header. Intermediate routes can process the streamlined IPv6 header more efficiently. IPv4 headers and IPv6 headers do not interoperate. IPv6 is not a superset of functionality, that is backward compatible with IPv4 is not possible. A host or router must use an implementation of both IPv4 and IPv6 to recognize and process both header formats. The IPv6 header is only twice as large as the IPv4 header, even though IPv6 addresses are four times as large as IPv4 addresses.
- IPv6 features a larger address space than that of IPv4.
- IPv6 offers a higher level of built-in security, and it has been specifically designed with mobile devices in mind.
- Unlike mobile IPv4, Mobile IPv6 (MIPv6) avoids triangular routing and is therefore as efficient as normal IPv6.
- IPv6 can easily be extended by adding extension headers after the IPv6 header.
- IPv4 limits packets to 64 KB of payload. IPv6 has optional support for packets over this limit, referred to as jumbograms, which can be as large as 4 GB.
- The use of jumbograms may improve performance over high-MTU networks. The presence of jumbograms is indicated by the Jumbo Payload Option header
- IPv6 also includes standardized support for QoS.
IPv4
- Source and destination addresses are 32 bits (4 bytes) in length.
- IPSec support is optional.
- IPv4 header does not identify packet flow for QoS handling by routers.
- Both routers and the sending host fragment packets.
- Header includes a checksum.
- Header includes options.
- Address Resolution Protocol (ARP) uses broadcast ARP Request frames to resolve an IP address to a link-layer address.
- Internet Group Management Protocol (IGMP) manages membership in local subnet groups.
- ICMP Router Discovery is used to determine the IPv4 address of the best default gateway, and it is optional.
- Broadcast addresses are used to send traffic to all nodes on a subnet.
- Must be configured either manually or through DHCP.
- Uses host address (A) resource records in Domain Name System (DNS) to map host names to IPv4 addresses.
- Uses pointer (PTR) resource records in the IN-ADDR.ARPA DNS domain to map IPv4 addresses to host names.
- Must support a 576-byte packet size.
- Source and destination addresses are 128 bits (16 bytes) in length.
- IPSec support is required.
- 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.
- All optional data is moved to IPv6 extension headers.
- Multicast Neighbor Solicitation messages resolve IP addresses to link-layer addresses.
- 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.
- IPv6 uses a link-local scope all-nodes multicast address.
- Does not require manual configuration or DHCP.
- Uses host address (AAAA) resource records in DNS to map host names to IPv6 addresses.
- Uses pointer (PTR) resource records in the IP6.ARPA DNS domain to map IPv6 addresses to host names.
- Must support a 1280-byte packet size .
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