Subject: [eap] Issue: Section 1 Problem Statement

From: "Bari, Farooq" <[email-masked]>
Date: Thu, 24 May 2007 12:03:53 -0700

This text works for me. thanks

Farooq Bari 
[email-masked] <mailto:[email-masked]>  
+1 425 580 5526 

________________________________

From: Bernard Aboba [mailto:[email-masked]] 
Sent: Thursday, May 24, 2007 8:34 AM
To: Bari, Farooq; [email-masked]
Subject: RE: [eap] Issue: Section 1 Problem Statement

Oops, forgot about the QoS issue.  Here is another stab at it:
 
""1.  Introduction
 
   Today, network access clients are typically preconfigured   
   with a list of access networks, and corresponding identities   
   and credentials.  However, as network access mechanisms   
   and operators have proliferated, it has become increasingly   
   likely that users will encounter networks for which no 
   preconfigured settings are available, yet which offer 
   desired services and the ability to successfully authenticate    
   with the user's home realm.  It is also possible that 
   preconfigured settings will not be adequate in some situations. 
   In such a situation, users can have difficulty in determining 
   which network to connect to, and how to authenticate to that network.
 
   The problem arises when any of the following conditions are true:
 
   o  Within a single network, more than one network attachment point 
      is available, and the attachment points differ in their roaming 
      arrangements, or access to services.  While the link layer 
      capabilities of a point of attachment may be advertised, 
      higher layer capabilities such as roaming arrangements,
      end-to-end quality of service or Internet access 
      restrictions may not be.  As a result, a user may have 
      difficulty determining what services are 
      available at each network attachment point, and which 
      attachment points it can successfully authenticate to.  
      For example, it is possible that a roaming agreement will 
      only enable a user to authenticate to the home realm from 
      some points of attachment, but not others.  Similarly, it 
      is possible that access to the Internet may be restricted 
      at some points of attachment, but not others or that
      end-to-end quality of service may not be available in all
      locations. In these situations, the network access client 
      cannot assume that all points of attachment within a network 
      offer identical capabilities.
 
   o  Multiple networks are available for which the user has no 
      corresponding pre-configuration. The user may not 
      have pre-configured an identity and associated credentials 
      for use with a network, yet it is possible that the 
      user's home realm is reachable from that network, 
      enabling the user to successfully authenticate.  
      However, unless the roaming arrangements are advertised,
      the network access client cannot determine apriori whether
      successful authentication is likely.  In this situation,
      it is possible that the user will need to try multiple
      networks in order to find one to which it can successfully
      authenticate, or it is possible that the user will not be 
      able  to obtain access at all, even though successful 
      authentication is feasible.
 
   o  The user has multiple sets of credentials.  Where no      
      preconfiguration exists, it is possible that the user will
      not be able to determine which credentials to use with which
      attachment point, or even whether any credentials it possesses
      will allow it to authenticate successfully.  An
      identity and associated credentials can be usable for
authentication
      with multiple networks, and not all of these networks will be
      preconfigured.  For example, the user could have one set of
      credentials from  a public service provider and  another set
      from an employer, and a network might enable authentication
      with one or more of these credentials.  Yet, without
      preconfiguration, multiple unsuccessful authentication attempts
      could be needed for each attachment point in order to determine
      what credentials are usable, wasting valuable time and
      resulting in user frustration.  In order to choose between
multiple
      attachment points, it can be helpful to provide additional
      information to enable the correct credentials to be determined.
 
   o  There are multiple potential roaming paths between the visited
      realm and the user's home realm, and service parameters or pricing
      differs between them.  In this situation, there could be multiple
      ways for the user to successfully authenticate using the same
      identity and credentials, yet the cost of each approach might
      differ. In this case, the access network may not be
      able to determine the roaming path that best matches the user's
      preferences.  This can lead to the user being charged more than
      necessary, or not obtaining the desired services.  For example,
      the visited access realm could have both a direct relationship
      with the home realm and an indirect relationship through a roaming
      consortium.  Current Authentication, Authorization and Accounting
      (AAA) protocols may not be able to route the access request to the
      home AAA sever purely based on the realm within the Network Access
      Identifier (NAI) [RFC4282].  In addition, payload packets can be
      routed or tunneled differently, based on the roaming relationship
      path.  This may have an impact on the available services or their
      pricing.
 
   In Section 2 the network discovery and selection problem is defined

   and divided into subproblems.  Some solution constraints are outlined
   in Section 3.  Section 4 provides conclusions and suggestions for
   future work.  Appendix A discusses existing solutions to portions of
   the problem."

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