RE: New (-02) version of IPv6 CPE Router draft is available for review

["Hemant Singh (shemant)" <shemant@cisco.com>]

Alain,

What is the concern if ULA is permanent and always present on the CPE
Router?  Till we see a strong justification for not having this mode of
operation on the router, we will not change the draft.  However, we do
collect input like yours (it's totally appreciated as well) and we will
keep it in mind to track for proper justification.

I have heard source-address selection issues but they are not sufficient
justification.  The SP also does not see these ULA in their network -
granted some day in future, the SP may, but then if ULA changes that
much to be globally routable, then the CPE Router specification also has
to change. 

The ULA has additional justification to be permanent.  The user at home
does not want to be nickel and dimed by the SP who can say, I will dole
out only one IA_PD to your home and that IA_PD is /56.  The ULA has a
much shorter prefix of /48 to serve the home network better. I want
devices in my home to have permanent IPv6 addresses - ULA gives me that,
GUA will not (GUA can be renumbered).  Permanent ULA in IPv6 is also
what the user is used to from IPv4 and it RFC1918 addresses - thanks
Brian Carpenter.

You see, we don't want to add another knob to the CPE Router or any new
state machine unless the knob or state machine is justified.  Please
show us a case where concurrent ULA and GUA on the CPE Router totally
breaks something and causes a major problem. 

Thanks.

Hemant

-----Original Message-----
From: Alain Durand [mailto:alain_durand@cable.comcast.com] 
Sent: Tuesday, July 22, 2008 10:57 AM
To: Hemant Singh (shemant); Brian E Carpenter
Cc: v6ops@ops.ietf.org; Wes Beebee (wbeebee)
Subject: Re: New (-02) version of IPv6 CPE Router draft is available for
review

Hemant,

I have no problem using ULA *in*the*absence*of* GUA. I understand that
the network has to be workable in the absence of upstream connectivity.

What I'd like to see is ULA being renumbered into GUA as soon as those
becomes available.

Brian is suggesting to have a mode where the user may also want to keep
the ULA *after* GUA are acquired, I'm fine with that as long as it is
not the default config.

   - Alain.


On 7/20/08 8:47 PM, "Hemant Singh (shemant)" <shemant@cisco.com> wrote:

> Alain,
> 
> Please go back to this draft's emails and see how Wes, I, and Remi 
> discussed the ULA case and a MUST requirement.  Your idea below is not

> valid because you have not considered the case of a standalone CPE 
> Router that is purchased from retail.  The user will power on the CPE 
> Router at home and the LAN interface(s) of the router will be up first

> - the user hasn't connected the WAN port yet to the broadband network.
> The user needs some IPv6 address to configure the CPE Router via the 
> web.  That is why the ULA will be used.  We have also said in our 
> draft that manual configuration is out of scope of our draft - 
> therefore we are not worried about details like how does the user get 
> to know the ULA prior to logging on to the CPE Router over the web 
> using this ULA.  If need be, we can also work on such details but 
> there is no dispensing with ULA.  I too like Brian's suggestion of 
> once per factory-reset and further I prefer a well-known ULA address 
> publishes apriori in the CPE Router manuals for the user to use that 
> address to configure the CPE Router.  After configuration, any other 
> ULA may be generated and the router reset to use the new ULA and
associated ULA prefix(es).
> 
> Only for the case when the CPE Router is embedded in a broadband 
> device like a modem and thus managed by the SP, the ULA's will not be 
> spawned as this is a WAN init first before LAN init model of our 
> draft.  See my other comments about WAN init first model also 
> complying with CableLab docsis 3.0 standards.
> 
> Hemant
> 
> -----Original Message-----
> From: Alain Durand [mailto:alain_durand@cable.comcast.com]
> Sent: Friday, July 18, 2008 11:53 PM
> To: Brian E Carpenter
> Cc: Hemant Singh (shemant); v6ops@ops.ietf.org; Wes Beebee (wbeebee)
> Subject: Re: New (-02) version of IPv6 CPE Router draft is available 
> for review
> 
> 
> 
> 
> On 7/18/08 11:42 PM, "Brian E Carpenter" <brian.e.carpenter@gmail.com>
> wrote:
> 
>>> I would rather like the text to recommend to only use ULA when 
>>> nothing else is available and immediately renumber to GUA when those
> are acquired.
>> 
>> IMHO that is only acceptable if there MUST be a configurable option 
>> to
> 
>> support a ULA (generated once per factory-reset) in parallel with a 
>> GUA, if that's what the user wants. I think that is needed for 
>> scenarios where people want addresses for devices that are guaranteed

>> never to reply to external packets.
> 
> I'd agree to this if, by default, parallel ULA support is off.
> 
>   - Alain.
> 
> 
>