Subject: Editorial review of draft-ietf-radext-management-authorization-03.txt

From: Bernard Aboba <[email-masked]>
Date: Tue, 24 Jun 2008 07:31:11 -0700 (PDT)

Abstract

   This document describes Remote Authentication Dial-In User Service
   (RADIUS) attributes for the authorization and service provisioning of
   Network Access Servers (NASes).  Both local and remote management are
   supported, with granular access rights and management privileges.
   Specific provisions are made for remote management via framed
   management protocols, and for specification of a protected transport
   protocol.

[BA] This document is about NAS management authorization, not 
authorization of NASes.  Suggest the following:

   This document specifies Remote Authentication Dial-In User Service   
   (RADIUS) attributes for Network Access Server (NAS) management. 
   Both local and remote management are
   supported, with granular access rights and management privileges.
   Specific provisions are made for remote management via framed
   management protocols, which may run over a secure transport
   protocol. 

2. Introduction and Rationale

[BA] How about combining Sections 2, part of 3 and 6 into a Section 1 that
reads as follows?  The Terminology section can then be Section 1.1. 

1. Introduction

   RFC 2865 [RFC 2865] defines the NAS-Prompt and Administrative values of 
   the Service-Type Attribute.   Both of these values provide access to 
   the interactive, text-based Command Line Interface (CLI) of the NAS, 
   and were originally developed to control access to the physical
   console port of the NAS, most often a serial port.  
  
   Remote access to the CLI of the NAS has been available in NAS 
   implementations for many years, using protocols such as Telnet,
   Rlogin and the remote terminal service of SSH.  In order to distinguish
   local, physical, console access from remote access, the NAS-Port-Type
   Attribute is generally included in Access-Request and Access-Accept
   messages, along with the Service-Type Attribute, to indicate the form 
   of access.  A NAS-Port-Type of Async (0) is used to signify a local
   serial port connection, while a value of Virtual (5) is used to
   signify a remote connection, via a remote terminal protocol.  This
   usage provides no selectivity among the various available remote
   terminal protocols (e.g.  Telnet, Rlogin, SSH, etc.).

   Today, it is common for network devices to support more than two
   privilege levels for management access than just NAS-Prompt
   (non-privileged) and Administrative (privileged).  Also, other 
   management mechanisms may be used, such as Web-based management,
   Simple Network Management Protocol (SNMP) and NETCONF.  
   To provide support for these additional features, this specification 
   defines attributes for framed management protocols, management protocol 
   security, and management access privilege levels. 

   Remote management via the command line is carried over protocols
   such as Telnet, Rlogin and the remote terminal service of SSH.  Since
   these protocols are primarily for the delivery of terminal or 
   pseudo-TTY services,  the term "Framed Management" is used to describe
   management protocols supporting techniques other than the command-line.
   Typically these mechanisms format management information in a binary or
   textual encoding such as HTML, XML or ASN.1/BER.  Examples include
   web-based management (HTML over HTTP or HTTPS), NETCONF (XML over
   SSH/BEEP/SOAP) and SNMP (SMI over ASN.1/BER).  Command line 
   interface, menu interface or other text-based (e.g. ASCII or UTF-8)
   terminal emulation services are not considered to be Framed Management
   protocols.

[BA] How about combining part of Section 3, as well as 4, 5 and 6 into
a Section 2 that reads as follows? 

2. Overview

   To support the authorization and provisioning of Framed Management
   access to managed entities, this document introduces a new value for
   the Service-Type Attribute [RFC2865], and one new attribute.  The new
   value for the Service-Type Attribute is Framed-Management, used for
   remote device management via a Framed Management Protocol.  The new
   attribute is Framed-Management-Protocol, the value of which specifies a 
   particular protocol for use in the remote management session.

   Two new attributes are introduced in this document in support of
   granular management access rights or command privilege levels.
   The Management-Policy-Id Attribute provides a text string
   specifying  a policy name of local scope, that is assumed to have
   been pre-provisioned on the NAS.  This use of an attribute to 
   specify use of a pre-provisioned policy is similar to 
   the Filter-Id Attribute defined in [RFC2865] Section 5.11. 

   The local application of the Management-Policy-Id within the managed
   entity may take the form of (a) one of an enumeration of command
   privilege levels, (b) a mapping into an SNMP Access Control Model,
   such as the View Based Access Control Model (VACM) [RFC3415], or (c)
   some other set of management access policy rules that is mutually
   understood by the managed entity and the remote management
   application.  Examples are given in Section X.

   The Management-Privilege-Level Attribute contains an
   integer-valued management privilege level indication.  This attribute
   serves to modify or augment the management permissions provided by
   the NAS-Prompt value of the Service-Type Attribute, and thus applies to 
   CLI management.

   To enable management security requirements to be specified, the
   Management-Transport-Protection Attribute is introduced.  The value 
   of this attribute indicates the minimum level of secure transport 
   protocol protection required for the provisioning of NAS-Prompt,
   Administrative or Framed-Management service.   

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