problem with IPv4 protocol [closed]

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using IPv4 protocol around 4 billion computers can be connected.(including classA, class B, class C networks). What should be done if the number exceeds beyond 4 billion? what are the consequences of such a situation?

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What should be done if the number exceeds beyond 4 billion?

Well, IPv6 is already largely supported by the current software and network infrastructure, so it is an obvious successor to IPv4.

Unfortunatley, migrating to IPv6 is a chicken-and-an-egg problem: the majority of Internet users aren't using IPv6 because ISPs and online services do not support it. However, ISPs do not want to support IPv6 because their customers are not demanding it. But the time will come once the IPv4 space starts to get tight.

Meanwhile, for access to legacy IPv4 sites, ISPs might share a single IPv4 address for several customers in a NAT configuration (network address translation). Currently NAT is mostly employed if you connect more than one computer to a router in a residental connection (if you've ever configured port forwarding, you need that because of NAT).

However, note that even though the number of allocated IPv4 addresses will reach 4 billion in a few years, the number of connected computers is much less than that -- because Internet address registries allocate addresses to ISPs in large groups (netblocks).

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IPv6

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... a move to IPv6 ?

A contentious subject since the Service Providers have some incentives to wait for a crisis to have a reason to charge additional fees...

Note that Mobile Networks are the early adopters of IPv6 (they use 4to6 gateways): since the major growth in connected devices come from the Mobile side, the fixed side will be dragged to IPv6 by force anyways.

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the address size in internet protocol version 6 (aka IPv6) is 128 bits.

that will allow for a theoretical number of 2^128 distinct IP addresses which should last for a while....