4 ms·
In most cases: * Only the last 64 bits of the address matter. The first 64 bits are routing information. * You have total control of the last 64. You can numb
by simoncion 11y ago
In most cases:
* Only the last 64 bits of the address matter. The first 64 bits are routing information.
* You have total control of the last 64. You can number your hosts however you like, in addition to -or instead of- using SLAAC and/or DHCPv6.
* If you're not using "Privacy Addresses", the last 64 remains stable even if your upstream changes your IPv6 allocation. So, host identification is trivial even if your assigned allocation changes.
- scurvy 11y agoYep. Only the first 64 bits matter. Almost every router out there is doing hardware forwarding in ASIC based on /64 and /128. In between /64 and /128 gets broken down into multiple /128's. That's what I've heard (and read) in a few places. Please correct me if I'm wrong.
- mixmastamyk 11y agoYou two disagree on which 64 bits matter. ;)
- simoncion 11y agoYep. :P For avoidance of confusion, if you're reading an IPv6 address as if it were a word written in the English language (that is, from left to right), the rightmost 64 bits are the ones that identify a host, and the leftmost are the routing information. :)
- scurvy 11y agoYeah, I was only looking at it from a router's perspective. Router's don't care much about the host stuff, and really, anything between a 64 or 128.
- simoncion 11y ago> Router's don't care much about the host stuff... Sure. But, I was addressing mixmastamyk's assertion: > I'm not a big fan of 128 bit addresses with ipv6, they are too long to read and write. Does anyone know why 64 bits was not good enough? [0] If you're okay with writing and reading 64-bit hex strings, [1] the part that matters to most folks is the host identification part, which is 64 bits long. :) [0] https://news.ycombinator.com/item?id=10837317 https://news.ycombinator.com/item?id=10837317 [1] I'm not... that's why I use DNS.