Using IPv6 with prefixes shorter than a /64 on a LAN

Owen DeLong owen at delong.com
Sun Jan 30 11:48:00 CST 2011


On Jan 30, 2011, at 8:39 AM, Leen Besselink wrote:

> On 01/25/2011 11:06 PM, Owen DeLong wrote:
>> 
>> 
>>> "640k ought to be enough for anyone."
>>> 
>> If IPv4 is like 640k, then, IPv6 is like having 47,223,664,828,696,452,136,959
>> terabytes of RAM. I'd argue that while 640k was short sighted, I think it is
>> unlikely we will see machines with much more than a terabyte of RAM
>> in the lifetime of IPv6.
>> 
> I would be very careful with such predictions. How about 2 TB of RAM ?:
> 
Yes... I left a word out of my sentence... I think it is unlikely we will see
COMMON machines with much more than a terabyte of RAM in
the lifetime of IPv6.

Sure, there will be the rare monster super-special-purpose thing with
more RAM capacity than there is storage in many large disk farms, but,
for common general purpose machines, I think it's safe to say that
47,223,664,828,696,452,136,959 terabytes ought to be enough for
anyone given that even at the best of Moore's law common desktops
will take 9 or more years to get to 1 Terabyte of RAM.

> "...IBM can cram 1 TB of memory into a 4U chassis or 2 TB in an
> eight-socket box in two 4U chassis..."
> 
> http://www.theregister.co.uk/2010/04/01/ibm_xeon_7500_servers/page2.html
> http://www.theregister.co.uk/2010/04/01/ibm_xeon_7500_servers/
> 
> I don't know who will use it or how much they will need to pay for it or
> even when they will be available,
> but they are talking about it (in this case at the last CEBIT in March).
> 
> People are building some very big systems for example with lots and lots
> of virtual machines.
> 
> 
Yes... My intent, like the 640k quote, was aimed at the common desktop
machine and primarily to show that since 1 TB is an inconceivably large
memory footprint for any normal user today, it's going to be a long long
time before 47,223,664,828,696,452,136,959 TB comes up short for
anyone's needs.

Owen






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