I agree with the way you are looking at it. I know it sounds impressive to talk about hosts, but in ipv6 all that matters is how many subnets do I have and how clean are my aggregation levels to avoid large wastes of subnets. Host addressing is not an issue or concern. So to talk about 128 bits instead of the reality of the 64 is silly. Owen DeLong <owen@delong.com> wrote:
On Sep 16, 2012, at 20:23 , Randy Bush <randy@psg.com> wrote:
[ yes, there are a lot of idiots out there. this is not new. but ]
"We are totally convinced that the factors that made IPv4 run out of addresses will remanifest themselves once again and likely sooner than a lot of us might expect given the "Reccomendations" for "Best Practice" deployment."
while i am not "totally convinced," i am certainly concerned. we are doing many of the same things all over again. remember when rip forced a homogenous, often classful, mask length in a network and we chewed through /24s? think /64 in ipv6, except it's half the bits not 1/4 of them. remember when we gave out As and Bs willy nilly? look at the giant swaths of v6 we give out today in the hopes that someone will deploy it.
and don't bs me with how humongous the v6 address space is. we once though 32 bits was humongous.
randy
We thought 32 bits was humongous in the context of a research project that would connect universities, research institutions and some military installations.
In that context, 32 bits would still be humongous.
Our estimation of humongous didn't change, the usage of the network changed dramatically. The experiment escaped from the laboratory and took on a life of its own. Once that happened, the realization that 32 bits wasn't enough was very nearly immediate.
The IPv6 address space offers 61 bits of network numbers each of which holds up to 64 bits worth of hosts. Obviously you never want to fill one of those subnets (nor could you with any available hardware), but it means that you don't have to waste time thinking about rightsizing network assignments.
I won't say we will never run out of IPv6 address space, but I will say that I'll be surprised if IPv6 doesn't hit a different limit first.
Guess what... If it turns out that our current behavior with respect to IPv6 addresses is ill-advised, then, we have 6+ more copies of the current IPv6 address space where we can try different allocation strategies.
Rather than fretting about the perils of using the protocol as intended, let's deploy it, get a working end-to-end internet and see where we stand.
Owen
-- Sent from my Android phone with K-9 Mail. Please excuse my brevity.