Which one is better in comparison of ipv4 vs ipv6? Internet Protocol version 6 is a new version of IP, designed to solve the problems that the previous version (Internet Protocol version 4) had when using it on the Internet, by using an address length of 128 bits instead of 32. IETF developed the protocol.
Currently, Internet Protocol version 6 is already used in several thousand networks around the world (more than 14,000 systems in the fall of 2013) but has not yet received such wide distribution on the Internet as Internet Protocol version 4. At the end of 2012, the share of Internet Protocol version 6 in network traffic was about 1%. By the end of 2013, growth was expected up to 3%.
Comparison with IPV4
It is sometimes argued that a new protocol can provide up to 5·1028 addresses per each inhabitant of the Earth. Such an ample address space was introduced for the sake of hierarchical addresses (this simplifies routing). However, an increased address space will make NAT optional. The classic use of Internet Protocol version 6 (over a/64 network per subscriber; only unicast addressing is used) will make it possible to use more than 300 million IP addresses per every inhabitant of the Earth.
The functions complicating the operation of routers have been removed from IPV6:
- Routers should no longer fragment a packet; instead, the packet is discarded with an ICMP MTU excess notification. The transmitting side of Internet Protocol version 6 is thus doomed to use Path MTU discovery technology. For the best performance of lossy protocols, the minimum MTU is raised to 1280 bytes. Fragmentation is supported as an option (information about packet fragmentation is removed from the main header in the extended header) and is possible only at the initiative of the sending party.
- The checksum is excluded from the IP header. Given that the channel (Ethernet) and transport (TCP and UDP) protocols have their checksums, another checksum at the IP level is perceived as redundant. Besides, modifying the hop limit field (or TTL in Internet Protocol version 4) on each router in Internet Protocol version 4 made it necessary to recalculate it continually.
- Despite the enormous size of the Internet Protocol version 6 address, thanks to these improvements, the packet header was only doubled: from 20 to 40 bytes.
Improvements to IPV6 compared to IPV4:
- In superfast networks, it is possible to support huge packets up to 4 gigabytes;
- Time to Live renamed Hop Limit;
- There are stream labels and traffic classes;
- Multicast broadcasting has appeared.
Autoconfiguration (SLAAC)
When initializing the network interface, it is assigned a local Internet Protocol version 6 address, consisting of the fe80::/10 prefix and the interface identifier located in the lower part of the address. The interface identifier is often the 64-bit extended unique identifier EUI-64, often associated with a MAC address. The local address is valid only within the network segment of the data link layer and is used for the exchange of information ICMPv6 packets.
To configure other addresses, a node can request information about network settings from routers by sending ICMPv6 the message “Router Solicitation” to the multicast address of routers. Routers that receive this message respond with ICMPv6 with a “Router Advertisement” message, which may contain information about the network prefix, gateway address, addresses of recursive DNS servers, MTU, and many other parameters.