Re: Using IPv6 with prefixes shorter than a /64 on a LAN

[Fernando Gont <fernando () gont com ar>]

On 26/01/2011 06:14 a.m., Owen DeLong wrote:
> > > That said.  Any size prefix will likely work and is even permitted by
> > > the RFC.  You do run the risk of encountering applications that assume
> > > a 64-bit prefix length, though.  And you're often crippling the
> > > advantages of IPv6.
> >
> > Just curious: What are the advantages you're referring to?
> 1.    Sparse addressing

This comes at a cost, though.


> 2.    SLAAC
> 3.    RFC 4193 Privacy Addressing

Privacy Extensions "solve" (*) a privacy issue *introduced* by SLAAC
embedding the MAC addresses in the IID. -- So, if anything, I deem this
as a patch, rather than a feature.

(*) there is some bibliography about the effectiveness of privacy
addresses. Some have even argued that they are harmful.


> 4.    Never have to worry about "growing" a subnet to hold new machines.

As in #1, this comes at a price.


> 5.    Universal subnet size, no surprises, no operator confusion, no bitmath.

With quite a bit of experience with subnetting (from IPv4), I doubt this
can be flagged as a benefit.

Thanks,
-- 
Fernando Gont
e-mail: fernando () gont com ar || fgont () acm org
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