Hi, Linda,

2013-01-29 à 07:54, [email protected] a écrit :

> 
> Hi,Remi 
>   
> 
> [email protected] 写于 2013-01-29 00:16:32:
> 
> > Senthil,
> > 
> > 
> > 2013-01-2815:24, Senthil Sivakumar (ssenthil) <[email protected]>  :
> > 
> > > I believe the prefix length > 64 should be allowed.
> > 
> > 
> > > It is upto the
> > > operator to choose the prefix length of their choice.
> > 
> > Agreed.
> > No one suggest to say the contrary.
> > 
> > Yet, operators have the constraint of RFC 4291 that "For all unicast
> > addresses, except those that start with the binary value 000, 
> > Interface IDs are required to be 64 bits long and to be constructed 
> > in Modified EUI-64 format".  
> > 
> > The draft says that:
> > (a) The PSID is:
> > +--+---+---+---+---+---+---+---+---+
> > |PL|   8  16  24  32  40  48  56   |
> > +--+---+---+---+---+---+---+---+---+
> > |64| u | IPv4 address  |  PSID | 0 |
> > +--+---+---+---+---+---+---+---+---+
> > (b) "If the End-user IPv6 prefix length is larger than 64, the most 
> > significant parts of the interface identifier is overwritten by the prefix."
> > 
> > This is particularly unclear:
> > - What happens to the u octet?
> > - And to the IPv4 address if the prefix is longer than /68? 
> 
> Remi, you mean the prefix is longer than /68 or /78?

Oops, I meant longer than 64 + 8, i.e. 72.
Thank you.

>    I think /68(64+4) prefix doesn't overwrite IPv4 address. 
> 
> BRs 
> Linda Wang 
> 
> 
> > - ...
> > 
> > Of course, if a use case is provided where MAP-E would be actually 
> > used with an IID shorter than 64 bits, it should be discussed. But:
> > - There is no such use case so far. 
> > - Looking for one doesn't seem useful. 
> > 
> > 
> > Regards,
> > RD
> > 
> >  
> > > 
> > > On 1/28/13 8:59 AM, "Ole Troan" <[email protected]> wrote:
> > > 
> > >>>>> 
> > >>>>> The examples in my previous note sort of provided backing for my view
> > >>>>> that the MAP endpoint IPv6 prefix can be limited to a maximum of a
> > >>>>> /64, thus making the IID fully conformant both to RFC 4291 and to RFC
> > >>>>> 6052.
> > >>>>> 
> > >>> ...
> > >>> 
> > >>>>> 
> > >>>>> I think limiting the prefix length to 64 bits is reasonable. Comments?
> > >>>> 
> > >>>> I don't think that's reasonable.
> > >>>> and I don't see what it buys us, given that supporting prefix lengths
> > >>>> longer than 64 is simple.
> > >>>> IPv6 isn't classfull, there isn't anything magic with the 64 boundary.
> > >>>> ;-)
> > >>>> 
> > >>>> cheers,
> > >>>> Ole
> > >>>> 
> > >>> 
> > >>> OK, then I agree with Rémi. Drop mention of prefixes greater than 64
> > >>> bits long and leave it to the reader to judge whether RFC 4291 imposes a
> > >>> limit.
> > >> 
> > >> you want this removed:
> > >>     <t>If the End-user IPv6 prefix length is larger than 64, the most
> > >>     significant parts of the interface identifier is overwritten by the
> > >>     prefix.</t>
> > >> 
> > >> I disagree. this is the only text in there suggesting to an implementor
> > >> that prefix lengths can be any value between 0-128.
> > >> 
> > >> Tom, Remi and I have stated our opinions. does anyone else have a view on
> > >> the matter?
> > >> 
> > >> cheers,
> > >> Ole
> > >> _______________________________________________
> > >> Softwires mailing list
> > >> [email protected]
> > >> https://www.ietf.org/mailman/listinfo/softwires
> > > 
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