Differences Between IPv4 and IPv6

The following table lists the important differences between IPv4 and IPv6.

IPv4 IPv6
IPv4 addresses are 32 bit length. IPv6 addresses are 128 bit length.
IPv4 addresses are binary numbers represented in decimals. IPv6 addresses are binary numbers represented in hexadecimals.
IPSec support is only optional. Inbuilt IPSec support.
Fragmentation is done by sender and forwarding routers. Fragmentation is done only by sender.
No packet flow identification. Packet flow identification is available within the IPv6 header using the Flow Label field.
Checksum field is available in IPv4 header No checksum field in IPv6 header.
Options fields are available in IPv4 header. No option fields, but IPv6 Extension headers are available.

Address Resolution Protocol (ARP) is available to map IPv4 addresses to MAC addresses.

Address Resolution Protocol (ARP) is replaced with a function of Neighbor Discovery Protocol (NDP).
Internet Group Management Protocol (IGMP) is used to manage multicast group membership. IGMP is replaced with Multicast Listener Discovery (MLD) messages.
Broadcast messages are available. Broadcast messages are not available. Instead a link-local scope "All nodes" multicast IPv6 address (FF02::1) is used for broadcast similar functionality.
Manual configuration (Static) of IPv4 addresses or DHCP (Dynamic configuration) is required to configure IPv4 addresses. Auto-configuration of addresses is available.
Related Tutorials
• Limitations of IPv4
• IPv6 History and related RFCs
• IPv6 Features
• Introduction to IPv6 Addressing
• IPv6 Address formats
• Types of IPv6 Addresses
• IPv6 Datagram Header Format