Re: correct

Le 15/06/2019 à 19:28, Warren Kumari a écrit :
> ' i
> 
> On Sat, Jun 15, 2019 at 10:59 AM Alexandre Petrescu 
> <alexandre.petrescu@gmail.com> wrote:
>> 
>> 
>> 
>> Le 06/06/2019 à 22:17, Warren Kumari a écrit :
>>> On Thu, Jun 6, 2019 at 2:46 PM Sander Steffann
>>> <sander@steffann.nl> wrote:
>>>> 
>>>> Hi Alexandre,
>>>> 
>>>>> I maintain that 1111 1110 10 equals 0x3fa, because that's
>>>>> what my Windows Calculator says: I type 1111 1110 10 and it
>>>>> converts to 0x3fa.
>>>>> 
>>>>> On another hand, I am rhetorically asked how can 1111 1110 10
>>>>> be 0x3fa?
>>>>> 
>>>>> (the 1111 1110 10 are the 10 leading bits of the IPv6 link
>>>>> local addresses, which is familiarly known to start with an
>>>>> fe80).
>>>>> 
>>>>> On my side, this is a difficulty to understand this 0xfe80,
>>>>> especially since 1111 1110 10 is so printed in Figure in
>>>>> RFC4291.
>>>> 
>>>> It's a prefix of an IPv6 address. IPv6 addresses are 128 bits
>>>> long. Expand to 128 bits and try again :)
>>>> 
>>>> 1111 1110 1000 0000 0000 0000 0000 0000 0000 0000 0000 0000
>>>> 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000
>>>> 0000 0000 0000 0000 0000 0000 0000 0000 equals
>>>> 0xfe800000000000000000000000000000. Not sure if Windows
>>>> Calculator can handle that though…
>>> 
>>> Windows calc probably can't, but: $ echo 'print hex(0b1111111010
>>> << (128-10))'  | python
>>> 
>>> or https://repl.it/repls/AwareDecentGeeklog if you don't have
>>> Python (because windows :-p)
>> 
>> For sake of completeness, google puts '1111111010 in hex' as
>> 0x423A3562.
> 
> Your point? One billion, one hundred and eleven million, one hundred
> and eleven thousand and ten is, in fact, 0x423A3562 In exactly the
> same way, if you enter '1+1' it gives you 2, and not 0b10.
> 
> Perhaps you actually meant "0b1111111010  to hex", which it
> correctly converts to 0x3FA.

True, that was the error.

> A number of people have (in my opinion very politely) suggested that 
> you spend some time reading up on subnetting. I'd second this 
> recommendation, and suggest "Internet Routing Architectures" by Sam 
> Halabi
> (http://www.ciscopress.com/store/internet-routing-architectures-9781578702336
>
> 
) - while it was written in 2000, and is focused on IPv4, the concept
> is *exactly* the same.
> 
> I suspect that, at this point, I'm simply being trolled -- 

I want to excuse to you and others if feeling trolled.  It is not my 
intention.

> unfortunately though, as the Operations AD I often have to counter
> the accusation that the IETF is detached from operations and doesn't 
> understand how protocols we design are used -- this thread fully
> plays into that.

I read it.

Alex

> 
> W
> 
>> 
>> qwant does not convert it.
>> 
>> Alex
>> 
>>> 
>>> W
>>>> 
>>>> Cheers, Sander
>>>> 
>>>> --------------------------------------------------------------------
>>>>
>>>> 
IETF IPv6 working group mailing list
>>>> ipv6@ietf.org Administrative Requests:
>>>> https://www.ietf.org/mailman/listinfo/ipv6 
>>>> --------------------------------------------------------------------
>>>
>>>
>>>
>
>>>> 
> 
> 