eap Mailing List: Re: Issue: Section 1 Problem Statement

[Bernard Aboba (bernard_aboba]

How about this? 
 
"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 cases, 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 parameters such as roaming arrangements 
      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.  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."

---

Subject: RE: [eap] Issue: Section 1 Problem Statement
Date: Thu, 24 May 2007 00:25:44 -0700
From: FB5431 [at] att.com
To: bernard_aboba [at] hotmail.com; eap [at] frascone.com

Hi Bernard,

 

Your revision of first para eliminates an important scenario for network selection from amongst networks with different capabilities even when they are form the same operator using same authentication method. So in this scenario multiple networks will be mapping to one “preconfigured operator name and access method” implying the preconfigured information is available but it is insufficient to do selection. I have tried to edit the first para as bellow..

 

“Today, network access clients are typically preconfigured with a list of access networks, and corresponding identities

and credentials.  However, as new network access technologies emerge and authentication mechanisms and operators have proliferated, it has become increasingly likely that users will encounter networks for which preconfigured settings in the client are either not available or insufficient, yet which can deliver desired services and can successfully authenticate the user to his home AAA server. In such a situation, users can have difficulty in determining which network to connect to, and how to authenticate to that network.”

 
Based on these changes minor change is also proposed to first sentence of first bullet as follows.
 
 “More than one network attachment point is available, and the attachment points differ in their roaming arrangements or access to services, or their capabilities such as QoS or belong to operators which the network access client is not preconfigured for.”


BR,

Farooq Bari
farooq.bari [at] att.com
+1 425 580 5526
 

---

From: Bernard Aboba [mailto:bernard_aboba [at] hotmail.com]
Sent: Wednesday, May 23, 2007 9:32 PM
To: eap [at] frascone.com
Subject: [eap] Issue: Section 1 Problem Statement

 

Issue: Section 1 Problem Statement

Submitter name: Bernard Aboba

Submitter email address: aboba [at] internaut.com

Date Submitted: May 23, 2007

Reference:

Document: NETSEL-07

Comment type: Editorial

Priority: S

Section: 1

Rationale/Explanation of issue:

In reading over Section 1, it is not clear to me that the essence of the problem has been clearly stated. 

I believe that the central issue here is that a user can encounter networks for which there is no preconfiguration. 

Also, I think there is an assumption that the networks that a user can encounter may restrict access to the Internet in some way so that all Internet services may not be accessible.  

I believe that these assumptions need to be more clearly spelled out.  Find enclosed below a rewrite of Section 1 that hopefully makes these assumptions more clear. 

"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 AAA server.  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  More than one network attachment point is available, and the

      attachment points differ in their roaming arrangements or 

      access to services, or belong to operators which the

      network access client is not preconfigured for.

      In this case, 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, 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 AAA server is reachable from

      that network, enabling the user to successfully authenticate.  

      While the local network's capabilities may be advertised, 

      where access to the Internet is restricted, it can

      be difficult for the user to determine apriori what services

      will be available upon connection. 

   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."