Explain like I'm five · Network

What is IPv6?

IPv6, told as a story about stretching an address system that ran out into a far longer new one.

so many houses now that the addresses ran outthe numbers in the old address system (IPv4) are all used up

The addresses have all run out.The numbers in the old address system (IPv4) are all used up.

address 1.2.3.4a new house can't get its own address — and sharing one is only a stopgap

Several houses are forced to share one address.A new house can't get its own address, and sharing one (NAT) is only a stopgap.

IPv4 address1 . 2 . 3 . 4IPv6 address2001:0db8:85a3:0000:0000:8a2e:0370:7334IPv6 = stretching the address system far longer, creating addresses that are practically endless

IPv6 stretches the address system far longer.Stretched from 4 groups to 8, creating addresses that are practically endless.

A much longer addressgrew from 32 bits to 128 bits
Practically endless countmore addresses than grains of sand on Earth
Self-assigning addressesa device can generate its own address
Needs compatibility workcan't talk directly to IPv4, so it needs a bridge
IPv4length — 4 groups (32 bits)count — about 4.3 billionNAT — almost requirednotation — 1.2.3.4IPv6length — 8 groups (128 bits)count — practically endlessNAT — mostly not needednotation — 2001:...:7334

IPv4 and IPv6 differ in length, count, need for NAT, and notation.IPv6 addresses are far longer and more plentiful than IPv4's, so NAT is mostly unneeded.

IPv6 officeIPv4 officefor now, IPv4 and IPv6 run side by side — a transition period (dual-stack)

The internet hasn't fully switched to IPv6 yet.For now, IPv4 and IPv6 run side by side — a transition period (dual-stack).

In one breath

IPv6 stretches the address system from 32 bits to a far longer 128 bits, creating a practically endless supply of new addresses.

IPv6 (Internet Protocol version 6) is the next-generation protocol that stretches address length to 128 bits, solving the exhaustion of IPv4's roughly 4.3 billion addresses. It can give every device its own unique address without NAT, and includes features like stateless address autoconfiguration (SLAAC). Since it isn't directly compatible with IPv4, transition techniques like dual-stack and tunneling are used alongside it.

When grown-ups say it

IPv6
The far longer new address system. 128 bits, written as 8 groups.
IPv4
The address system used from the start. 32 bits — only about 4.3 billion addresses.
NAT
The stopgap of forcing several houses to share one address. Mostly unnecessary under IPv6.
Dual-stack
Running both an IPv4 and an IPv6 post office during the transition. Widely used right now.
SLAAC
A device generating and assigning itself an address. IPv6's own automatic-assignment method.
Dynamic routing protocol
The rule letting post offices redraw their map themselves. The map still has to keep redrawing itself under the new addresses. → the delivery map that redraws itself
Socket
A dedicated hole made from an address and a room number. The house part of a socket address is moving to this system. → the dedicated mailbox hole
DNS
The neighborhood address book. With addresses this long, the address book matters even more. → the neighborhood address book
Next story
The Delivery Network With a Lane for Every Need →
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