Re: More CPE

[Mark Smith <ipng@69706e6720323030352d30312d31340a.nosense.org>]

Hi Miguel,

On Fri, 11 Jan 2008 09:23:07 +0100
"Miguel A. Diaz" <miguelangel.diaz@consulintel.es> wrote:

> > -----Mensaje original-----
> > De: Mark Smith 
> > [mailto:ipng@69706e6720323030352d30312d31340a.nosense.org] 
> > Enviado el: jueves, 10 de enero de 2008 11:52
> > Para: miguelangel.diaz@consulintel.es
> > CC: v6ops@ops.ietf.org
> > Asunto: Re: More CPE
> > 
> > On Thu, 10 Jan 2008 10:54:22 +0100
> > "Miguel A. Diaz" <miguelangel.diaz@consulintel.es> wrote:
> > 
> > > If both RA and DHPCPv6 are setup in the WAN port, the ISP has to 
> > > manage two prefix pools: one for the point-to-point link 
> > (RA) and the 
> > > other one for the delegated prefix (usually /48).
> > > 
> > > That can be avoided by getting one /64 for the point-to-point link
> > > (RA) from the delegated prefix (/48) as explained at
> > > 
> >
> http://www.consulintel.euro6ix.org/ietf/draft-palet-v6ops-point2point-
> > > 01.txt
> > > 
> > > This approach has benefits from both operational and routing 
> > > aggregation perspectives and it may be taken into account 
> > by both ISPs 
> > > and CPEs manufacturers.
> > 
> > I'm personally not against this addressing method, however 
> > I'm not all that sure that might be a good idea for the 
> > customers. "Stealing" a /64 out of the customer's /48 creates 
> > opportunities for the customer to accidently use it on their 
> > side of the CPE, breaking their external connectivity. This 
> > probably would only happen occasionally (although as an ISP 
> > you'd probably want to avoid the first 5, 20 or 100 /64s), 
> > however when you have 10 000s or 100 000s customers, those 
> > occasions can start to occur quite often, and those are calls 
> > your helpdesk has to receive and deal with.
> > 
> 
> Not sure if that will happen very likely. Most of the residential
> users don't know anything about networking, so they just follow the
> instructions from their ISPs and/or CPEs. Probably they will have one
> only router (the CPE) which in the event this addressing method is a
> convention it will prevent the assignment of the WAN /64 to other LAN
> port.
> 
> In case of advanced users and or network administrators in
> enterprises, there's nothing new with this addressing method. Those
> users are supposed to be able to manage ip address allocation in the
> same way that currently happens with IPv4: if they receive an IPv4 /29
> from their ISP, they must be able to know what IP is broadcast, what
> the gateway, etc, and not re-use it in the internal network.
> 
>

Another thought I've had is SOHO users might be interested in being
dual homed to the same upstream ISP. So at least 2 /64s would have to
be reserved and avoided out of the customers /48. I don't think we
can reserve the first two, as I'm pretty sure people will commonly
number their first subnet number one.

The first and last subnets might be ok, although renumbering the last
subnet of a /56 to the last subnet of a /48 if the customers prefix
length is shortened is something that probably would need to be done for
consistency. People are likely to forget subnet 0x00ff out of their /48
is taken if it isn't renumbered.

Regards,
Mark.