Re: 1111 1110 10 equals 0xfe80 to 0xfebf

[Alexandre Petrescu <[e-mail]>]

Le 07/06/2019 à 21:29, Mudric, Dusan (Dusan) a écrit :
>>
>> Message: 3
>> Date: Fri, 7 Jun 2019 10:53:28 -0700
>> From: Fred Baker <[e-mail]>
>> To: Alexandre Petrescu <[e-mail]>
>> Cc: IPv6 <[e-mail]>
>> Subject: Re: Is 1111 1110 10 equal to 0xfe80 or 0x3fa?
>> Message-ID: <[e-mail]>
>> Content-Type: text/plain; charset="us-ascii"
>>
>>
>>
>> If I have prefix fe80::/10, as described in RFC 4291, the next bit is bit 11. Doing
>> the same subdivision of the prefix is fe80::/11 and fea0::/11.
> [Dusan] The hexadecimal definition for LL address is not syntactically correct. The binary 10 bit prefix 1111111010 cannot be presented as hexadecimal FE80::/10. It is rather a range FE80::/10 - FEBF::/10. In this notation, FE80::/10 = FEBF::/10, 

I agree.  The IPv6 link-local prefix is not one hextet, but a range of 
hextets: FE80::/10 to FEBF::/10.

Maybe one can come up with a base in which that range of hextets is 
represented as just one number.

Alex

  because the first 10 bits are equal and other 6 should be ignored. 111 
1111010 can be defined as FE80::/10 only if every time it is also 
mentioned that the trailing 6 bits are all zero. But, it is very common 
to say FE80::/10 is LL prefix, without mentioning the 6 trailing bits to 
be zeros.
> 
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