Re:Ripe NIC: 'In Five Weeks We'll Run Out of IPv4 Internet A...
by mlyle on Tuesday October 29, 2019 @01:08AM
(#21384381)
As said by others, you need hierarchy to avoid routing tables becoming excessively large-- that's the real limit.
Since an IPv6 subnet can hold effectively any number of hosts, and it's easier to give bigger chunks of networks, the chances that a given org needs multiple assignments is much lower. In turn we use that real limit (routing table size) more responsibly.
If routing tables can be much bigger in the future, we also have a whole lot more room to grow / allocate it differently. The chunk from which allocation is occurring (2000/3, plus the multicast and link local blocks, etc) is less than 1/4th the space; furthermore, more than half of the space within this is reserved.
Since an IPv6 subnet can hold effectively any number of hosts, and it's easier to give bigger chunks of networks, the chances that a given org needs multiple assignments is much lower. In turn we use that real limit (routing table size) more responsibly.
If routing tables can be much bigger in the future, we also have a whole lot more room to grow / allocate it differently. The chunk from which allocation is occurring (2000/3, plus the multicast and link local blocks, etc) is less than 1/4th the space; furthermore, more than half of the space within this is reserved.
https://www.iana.org/assignments/ipv6-unicast-address-assign...