number of Valid hosts in IPv6?

Anyone knowing about the Address divisions in IPv6?

networking

user420878

Posted 2011-02-13T18:08:26.810

Reputation:

Any specific information you need that isn't described here?http://en.wikipedia.org/wiki/IPv6

– GolezTrol – 2011-02-13T18:10:45.597

i was trying to find out number of valid hosts in ipv6 as we can calculate in ipv4 using classes and all – None – 2011-02-13T18:11:43.463

Answers

The most common divisions are:

/64 - a single subnet, i.e. one LAN
/56 - smallest per-customer assignment
/48 - typical per-customer assignment
/32 - typical allocation to a Local Internet Registry (LIR) from their Regional Internet Registry

Alnitak

Posted 2011-02-13T18:08:26.810

Reputation: 656

so does it mean 2^64-1 hosts in first case? – None – 2011-02-13T18:13:24.603

kind of, yes, although of course you could never put that many in one network ;-) – Alnitak – 2011-02-13T18:14:45.147

so total number of valid hosts possible would be? they will obviously depend upon the subnetting that we're using and hence will be variable i guess... isnt it so? – None – 2011-02-13T18:17:42.577

Theoretically, the largest amount of hosts ip6 can host is 2^128, just like ip4 can host 2^32. – surfasb – 2011-02-14T15:01:29.167

Ooops!!! There is some confusion about minimum Ipv6 prefix. the /64 prefix MAY be selected for dynamic allocation under Local Unicast (fe80::) but this does not mean for all Global Unicast, according to RFC4291. Initially, the minimum prefix that will be allocated BY IANA (not by Internet Providers) is /64. This means that anyone with equipments connected to INTERNET MUST have ANY network prefix below /64. BTW, /65..../128 are ALSO valid. There is only one restriction: The IP must be unique. The condition of host addressing using EUI-64 MAY be used at Global Unicast outside range of FE80:: but MUST be used for FE80:: host addressing.

Uli

Posted 2011-02-13T18:08:26.810

Reputation: 11

My consumer-grade subscription uses a /48, so IANA must have given my ISP a larger block. Wikipedia claims in "General allocation": RIRs assign smaller blocks to ISPs, which then distribute this in /48 sized parts to their clients. And finally, an IANA draft IPv6 Addressing Plans: All [see notes] customers get one /48 unless they can show that they need more than 65k subnets.

– Arjan – 2011-02-16T07:46:10.060