Re: [EXTERNAL] Re: [v6ops] Scope of Unique Local IPv6 Unicast Addresses (Fwd: New Version Notification for draft-gont-6man-ipv6-ula-scope-00.txt)

[Fernando Gont <[e-mail]>]

On 18/2/21 20:39, Manfredi (US), Albert E wrote:
> -----Original Message-----
> From: ipv6 <[e-mail]> On Behalf Of Fernando Gont
> 
>> Well, this is a spec inconsistency. You have one spec (RFC4007) defining
> "scope" and "global scope", and another specs:
>>
>> a) making use of the same terms in an incorrect way, or,
>>
>> b) employing same terms but with a different definition.
>>
>> i.e., either the definition in RFC4007 is incorrect, or the use in
> RFC4193 and implicit use in RFC4291 is incorrect.
> 
> You can also argue, if there are prefix bits sent in the clear, and those prefix bits are used to send the packets to a pre-determined gateway, and that gateway is then used to decrypt all of the remaining address bits, then route packets through a walled garden intranet with global span, then global scope could still apply.

"global span" is defined as "Internet-wide" span. i.e., if an address 
does not unambiguously specify an interface Internet-wide, it's not 
global scope as per RFC4007.



> Just sayin'. These still aren't like RFC 1918.

The only practical differences I see with respect to rfc1918 are:

1) ULAs are not intended to be used with NAT.
However, were RFC1918 strictly specified to be employed along with NAT? 
Besides "not indended" != "won't be".

2) ULAs are intended to have a small probability of collision when a 
subset of ULA-based networks are interconnected.

This is the product of mandating that some bits are generated from a 
PRNG, plus the fact that ULAs have more bits than their RFC1918 counterpart.

If I have missed any other differences, please enlighten me. :-)

Thanks,
-- 
Fernando Gont
SI6 Networks
e-mail: [e-mail]
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