Re: Permanent ULA support in home networking (Re: New (-02) version of IPv6 CPE Router draft is available for review)

[Rémi Denis-Courmont <rdenis@simphalempin.com>]

On Tue, 22 Jul 2008 18:38:33 -0400, Alain Durand

<alain_durand@cable.comcast.com> wrote:

> On 7/22/08 6:33 PM, "Hemant Singh (shemant)" <shemant@cisco.com> wrote:

> 

>> I don't believe apps have to know topology if apps receive a GUA and a

>> ULA. The app has to just ignore the ULA.

> 

> Exactly my point. Apps need to be made aware of the difference between

ULA

> & GUA, which is what the ULA proponents have been saying all along will

not

> be necessary.



That depends how the applications learn the ULA in the first place...



If an application uses referral, it might well be that the rendez-vous

mechanism provides GUA even for on-link hosts, so the application will not

even see the ULA ever and there will be no issues. For an Internet-wide

service, I would expect the application to connect to a global location

server (from/to GUA) and register that source address, the GUA, with the

service.



Conversely, if the service is not intended to work outside of the LAN: it

is OK for my file sharing and printing service to use ULA in referrals

because it is not supposed to work from the outside in the first place.



-- 

Rémi Denis-Courmont