Re: [Pana] and network selection

Hi Avi,

On Thu, Nov 04, 2004 at 02:06:52PM -0500, Avi Lior wrote:
> Hi Yoshihiro,
> 
> > Network selection based on EAP occurs always after completion 
> > of network selection in PANA in its discovery and handshake 
> > phase (this is guaranteed because section 5.12.1 of 
> > pana-pana-06 explcitly prohibits piggybacking EAP-Request in 
> > PANA-Start-Request messsage). This means that network 
> > selection based on EAP is only performed under the chosen ISP.
> 
> I am a bit confused here.  So let me ask you a few questions:
> 
> What is the purpose of ISP-Information?

It is used by the PaC to choose an ISP.

> How does the PAA know what ISP-Information to provide to the PaC?

It is assumed that the PAA knows which ISPs are available in the
visited network.  The PAA does not have to advertise the list of home
ISPs that are not directly connected to the visited network.

> If the PAA has a relationship with hunderds of ISPs does it send all the
> ISPs?

Yes.  But I assume that only the list of ISPs in the visited network
is advertised (not the home ISPs with which the visited network ISPs
have relationship), and I don't think there are hundreds of ISPs in
the visited network in most cases.

> How does the PaC select which ISP?

This is up to implementation.

> 
> Note: the visited network may not have a direct relationship with the home
> network 

The home ISP network information is not advertised in PANA, assuming
that the subsribers has a knowledge on which ISP in the visited
network has direct/indirect relationship with its home ISP.

> So it will send a list of intermediaries to the PaC.  The PaC may not be
> able to select the intermediaries because it wouldn't necessarily know the
> routing.  It knows its home network for sure but it may not know other
> relationships.

This list of intermediaries are carried in EAP message (note: PANA
itself does not support any intermediaries selection) and this happens
after the PaC chooses an ISP in the visited network through PANA.  So
if you use EAP-based network selection during PANA authentication
phase, you can choose an intermediary in the scope of the chosen ISP.

> 
> When we do EAP based authentication in AAA we use the User-Name the NAI to
> determine how to route the AAA requests to the Home Network.  How is this
> invisioned to work when PANA and AAA work together.

You just specify a correct NAI in an EAP-Request/Identity or an EAP
method-specific identity message during PANA authentication phase.

> 
> When we do the authentication part, the AAA will use the NAI that was
> provided by the device to route the authentication requests.  This may be
> totally different then the ISP selected during the discovery phase.

When the PaC chooses an ISP, it is the responsibility of the PaC to 
specify an NAI in EAP that is routed correctly through the chosen ISP.

> 
> So what is the purpose of doing ISP selection in the discovery phase? 

To provide the PaC a way to choose an ISP without relying on the
NAI-based selection, which requires different identifies for choosing
different ISPs.  Since PANA has ISP selection mechanism, the PaC can
use the same identity ohba@visa.com and still choose an ISP among
multiple ISPs, as long as those ISPs have relationship with visa.com.

Regards,

Yoshihiro Ohba

> 
> 
> > -----Original Message-----
> > From: Yoshihiro Ohba [mailto:yohba@tari.toshiba.com] 
> > Sent: Tuesday, November 02, 2004 9:32 PM
> > To: Avi Lior
> > Cc: 'Alper Yegin'; pana@ietf.org
> > Subject: Re: [Pana] and network selection
> > 
> > 
> > Hi Avi,
> > 
> > I think network selection in PANA (that is ISP selection) and 
> > the network selection based on EAP (that is intermediary network
> > selection) does not conflict each other for the following reason:
> > 
> > Network selection based on EAP occurs always after completion 
> > of network selection in PANA in its discovery and handshake 
> > phase (this is guaranteed because section 5.12.1 of 
> > pana-pana-06 explcitly prohibits piggybacking EAP-Request in 
> > PANA-Start-Request messsage). This means that network 
> > selection based on EAP is only performed under the chosen ISP.
> > 
> > I agree that we should clarify somethign like this in the 
> > PANA specification draft.
> > 
> > Regards,
> > 
> > Yoshihiro Ohba
> > 
> > 
> > On Wed, Nov 03, 2004 at 03:22:46PM -0500, Avi Lior wrote:
> > > 
> > > Issues with Network Selection.
> > > 
> > > PANA provides its own network selection and EAP also provides a 
> > > network discover mechanism 
> > > (draft-adrangi-eap-network-discovery-05.txt)
> > > 
> > > These may conflict with each other.  Furthermore, the PAA 
> > may not know 
> > > that the EAP payload contains network discovery material.
> > > 
> > > What happens if both are used?  Is it something that PANA 
> > needs to be 
> > > concerned about? Do we need to say something about this in PANA?
> > > 
> > > 
> > > 
> > > 
> > > _______________________________________________
> > > Pana mailing list
> > > Pana@ietf.org
> > > https://www1.ietf.org/mailman/listinfo/pana
> > 

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