Re: [irtf-discuss] Why do we need to go with 128 bits address space ?

Incorrect.

On Sat., 17 Aug. 2019, 01:43 Phillip Hallam-Baker, <phill@hallambaker.com>
wrote:

> On Thu, Aug 15, 2019 at 6:31 AM Brian Carpenter <
> brian.e.carpenter@gmail.com> wrote:
>
>> e) 64 isn't enough to allow lots of bits for topology plus lots of bits
>> for privacy
>> f) in any case we can compress the headers in low power, low bandwidth
>> scenarios
>> g) it's 25 years too late for this discussion even if we were wrong
>>
>
> Perhaps.
>
>
> The reason we went to 128 bits was 64+64 = 128
>
> It was assumed that networks would want to map MAC addresses onto the
> lower bits of the address and those were already in the process of
> expanding to 64 bits. This hasn't happened because it is nonsense.
> Disclosing the structure of your internal network to potential attackers is
> stupid.
>
> IPv6 to IPv6 NAT is going to be seen as an essential security control in
> future zero trust/zero knowledge networks. I don't want Mallet knowing if I
> have 4 hosts in my network or 400 and I am going to try to make it as
> difficult and expensive as possible for him to find out. So instead of
> allocating one IPv6 address to my hosts, I will allocate multiple addresses
> and apply encryption to obfuscate them at the network boundary.
>
> This approach can provide a lot of leverage against DoS attacks. The Mesh
> service protocols make it possible for a Mesh service to assign each
> account a separate IPv6 address for client access. That in turn makes it
> possible for border controls to drop packets that are from accounts that
> are flooding or not associated with an account at all.
>
> It is easier to find an encryption cipher with a 64 bit block size than
> 48. They are not going to be any use for general purpose encryption but
> they would serve this one.
>
>
> It was also assumed that there was a need for more routable IP addresses
> which was probably a mistake.
>
> In IPv4, every host has an Internet has a routable address. So if Google
> has 32,368 hosts at the same site, that means 32,368 routable addresses.
> The design for IPNG did not take account of the fact that if we append a
> non-routable portion, those hosts can all sit on the same routable address.
>
> So yes, one could argue that 32+32 would have been enough. Only there are
> more than 4 billion people on the planet. So you have to have at least 40
> bits for the routable addresses and once you take account of inefficiency
> in the allocation process we need a minimum of 48 bits. Given the vast cost
> of the change, 64 bits looks like a reasonable choice to me.
>
>
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