Re: [v6ops] RFC6459 "IPv6 in 3GPP" - the IID in the LL address

[<[e-mail]>]

Re-,

Please see inline.

Cheers,
Med

> -----Message d'origine-----
> De : Alexandre Petrescu [mailto:[e-mail]]
> Envoyé : lundi 10 juillet 2017 16:46
> À : BOUCADAIR Mohamed IMT/OLN; [e-mail]
> Objet : Re: [v6ops] RFC6459 "IPv6 in 3GPP" - the IID in the LL address
> 
> 
> 
> Le 10/07/2017 à 16:16, [e-mail] a écrit :
> > Alex,
> >
> > I'm focusing on this part of your answer.
> >
> > Please see inline.
> >
> > Cheers, Med
> >
> >> -----Message d'origine----- De : Alexandre Petrescu
> >> [mailto:[e-mail]] Envoyé : lundi 10 juillet
> >> 2017 15:51 À : BOUCADAIR Mohamed IMT/OLN; [e-mail] Objet :
> >> Re: [v6ops] RFC6459 "IPv6 in 3GPP" - the IID in the LL address
> >>
> >> Med,
> >>
> >>
> >>>> This has consequences on privacy, and may impact
> >>>> interoperability when DHCPv6-PD is used later in the process.
> >>>
> >>> [Med] I don't follow you here. There is no privacy concern out
> >>> there. The IID used when forming a global IPv6 address will be
> >>> selected by the terminal; no assumption is made about those
> >>> bits.
> >>
> >> There is a privacy concern: if the operator enforces the UE to
> >> always use the network-assigned IID then that UE is trackable.
> >>
> >
> > [Med] I'm not sure what you mean by "trackable" in this context. If
> > you mean that "a UE can be identified by the network", then an UE is
> > always identified by the network it connects to!
> 
> YEs, and I thought that is a device-specific identifier like the IMEI,
> not the link-local address.
> 
> > At the IP level, an UE is identified by the bits of the IPv6 prefix,
> >  not IID bits.
> 
> Well - by the IP address.

[Med] No. I reiterate my answer: it is identified by the prefix not the full IPv6 address.  Policies at the network are enforced based on the prefix, not the full IPv6 address.  

> 
> > Further, a network does not need IP-related information to identify
> > an UE.
> 
> I agree, so why does it want to impose an IID to the UE?

[Med] This is an optimization to avoid DAD. 

> 
> > I still don't see any privacy concern in supplying an IID to an UE
> > to be used for forming its link-local address.
> 
> Err...
> 
> It's because the supplied IID is very much like an IEEE MAC 48bit
> address. 

[Med] This is a link-local address not a GUA. So, not sure to understand your point. 

 It is guaranteed unique, so it can also be used to track.

[Med] to be tracked by whom?

> 
> Why do you think it can not be used to track?
> 
> Alex
> 
> >
> >
> >