Nepedia
Back to Discover
Advanced Reader
💻

IPv6

technology Maturity 11-13 Next article →

Internet Protocol version 6, or IPv6, is the most recent version of the Internet Protocol (IP). This is a communications protocol that provides an identification and location system for computers on networks. It is essential because it routes traffic across the Internet.

Every device on the Internet is assigned a unique IP address for identification. As the Internet grew rapidly after its commercialization in the 1990s, engineers realized the existing system could not support enough devices. IPv6 was developed by the Internet Engineering Task Force (IETF) to solve the problem of IPv4 address exhaustion. It was intended to replace the older version, IPv4, to ensure the global network could continue to expand.

The mechanism of IPv6 relies on a much larger addressing space than its predecessor. While IPv4 uses 32-bit addresses, IPv6 uses 128-bit addresses.

IPv6 address terminology-en
IPv6 address terminology-en

This change yields a massive address space of 2^128, which is approximately 340 undecillion total addresses. An IPv6 address is represented as eight groups of four hexadecimal digits each. These groups are separated by colons. For example, a full address can be shortened using specific rules to make it easier to read. Because the address space is so large, the network identifier part is usually 2^64 addresses. This makes the subnet size about four billion times larger than the entire IPv4 address space.

IPv6 uses different types of transmission to move data. The architecture allows for three distinct types: unicast, anycast, and multicast.

IPv6 multicast address stracture-en
IPv6 multicast address stracture-en

Unicast involves sending a packet to a single specific destination. Multicast allows a single packet to be sent to multiple destinations at once. IPv6 expanded and simplified multicast addressing to provide better optimization for service delivery. Interestingly, IPv6 does not implement traditional broadcast, which sends a packet to every host on a link. Instead, it uses a specific link-local all-nodes multicast group to achieve a similar result. This design helps make the delivery of data more efficient across different networks.

The history of these protocols began with IPv4, which was originally a research project by DARPA. DARPA is a United States Department of Defense agency. IPv4 provided approximately 4.3 billion addresses, which seemed sufficient at first. However, as the Internet became a global tool, these addresses became scarce.

IPv4 address structure and writing systems-en
IPv4 address structure and writing systems-en

By February 2011, the last unassigned top-level blocks of 16 million IPv4 addresses were allocated by the Internet Assigned Numbers Authority (IANA). Eventually, the five regional Internet registries, or RIRs, reached a stage where they could only provide very small blocks of addresses. RIPE NCC, one of these registries, announced it had fully run out of IPv4 addresses on 25 November 2019.

Rir-ipv6-allocation-rate
Rir-ipv6-allocation-rate

This exhaustion made the transition to IPv6 a critical necessity.

IPv6 provides several technical benefits that improve how routers process data. The IPv6 packet header is designed to be simpler than the IPv4 header.

Ipv6 header
Ipv6 header

This simplicity minimizes the processing work required by routers when they forward packets. Many rarely used fields have been moved to optional header extensions. This allows routers to focus on the most important information. Additionally, IPv6 places the responsibility for packet fragmentation on the end points rather than the routers. This change further simplifies the work of the routers in the middle of a network. It also allows for hierarchical address allocation, which helps limit the expansion of routing tables across the Internet.

One important feature of IPv6 is Stateless Address Autoconfiguration, known as SLAAC. This allows hosts to configure themselves automatically when they connect to a network.

IPv6 headers sequence-en
IPv6 headers sequence-en

Every interface has a self-generated link-local address. Routers then provide network prefixes via router advertisements. This makes it much easier to manage a network. If a network changes its connectivity provider, IPv6 allows for easier renumbering. In IPv4, changing a network prefix is a major effort. In IPv6, changing the prefix announced by a few routers can renumber an entire network. This is possible because the host identifiers can be independently self-configured.

Security and privacy are also central to the design of IPv6. Because every device can have a unique, globally addressable IP address, tracking a device across networks becomes easier. This is a concern for mobile devices like cell phones. To help, the SLAAC protocol includes "temporary addresses" to protect privacy. These addresses are random and unstable. A typical device might generate a new temporary address every day. This makes it harder for others to track a specific device over long periods. Furthermore, while Internet Protocol Security (IPsec) was originally developed for IPv6, it is now a recommendation for many implementations. This helps ensure that devices from different vendors can still communicate securely.

765 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (14)
File:IPv6 header-en.svg
IPv6 header-en.svg
File:IPv6 address terminology-en.svg
IPv6 address terminology-en.svg
File:IPv4 address structure and writing systems-en.svg
IPv4 address structure and writing systems-en.svg
File:IPv6 multicast address stracture-en.svg
IPv6 multicast address stracture-en.svg
File:IPv6 headers sequence-en.svg
IPv6 headers sequence-en.svg
File:Ipv6 header.svg
Ipv6 header.svg
File:IPv6 address stracture-en.svg
IPv6 address stracture-en.svg
File:IPv6 link local unicast address structure-en.svg
IPv6 link local unicast address structure-en.svg
File:IPv6 global unicast address stracture-en.svg
IPv6 global unicast address stracture-en.svg
File:IPv6 Prefix Assignment Example-en.svg
IPv6 Prefix Assignment Example-en.svg
File:IPv6 IPv4-Compatible address structure-en.svg
IPv6 IPv4-Compatible address structure-en.svg
File:IPv6 IPv4-Mapped address structure-en.svg
IPv6 IPv4-Mapped address structure-en.svg

+ 2 more

More to explore

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.