Configuration Guide for Cisco NCS 1001, IOS XR Release 7.8.x
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This chapter describes the implementation of the administrative model of task-based authorization used to control user access
in the software system.
Table 1. Feature History
Feature Name
Release Information
Feature Description
OC support for AAA user
Cisco IOS XR Release 7.3.2
This feature allows all authorized users on XR VM to access administration data on the router through NETCONF or gRPC interface,
similar to accessing the CLI. This functionality works by internally mapping the task group of the user on XR VM to a predefined
group on System Admin VM. Therefore, the NETCONF and gRPC users can access the administrative information on the router even
if their user profiles do not exist on System Admin VM.
Command added:
aaa authorization (System Admin-VM)
Understanding of AAA
User groups and task groups are configured through the software command set used for authentication, authorization and accounting
(AAA) services. Authentication commands are used to verify the identity of a user or principal. Authorization commands are
used to verify that an authenticated user (or principal) is granted permission to perform a specific task. Accounting commands
are used for logging of sessions and to create an audit trail by recording certain user- or system-generated actions.
AAA is part of the software base package and is available by default.
To configure authentication, authorization, and accounting (AAA) authentication at login, use the aaa authentication login command in global configuration mode.
Admin Access for NETCONF and gRPC
This feature allows all authorized users on XR VM to access administration data on the router through NETCONF or gRPC interface,
similar to accessing the CLI. This functionality works by internally mapping the task group of the user on XR VM to a predefined
group on System Admin VM. Therefore, the NETCONF and gRPC users can access the admin-related information on the router even
if their user profiles do not exist on System Admin VM.
NETCONF is an XML-based protocol used over Secure Shell (SSH) transport to configure a network. Similarly, gRPC is an open-source
remote procedure call framework. The client applications can use these protocols to request information from the router and
make configuration changes to the router. Prior to Cisco IOS XR Software Release 7.3.2, users who use NETCONF, gRPC or any
other configuration interface, other than CLI, to access the admin-related information on the router, had to belong to user
groups that are configured on System Admin VM. Otherwise, the router would issue an UNAUTHORIZED access error message and
deny access through that client interface.
By default, XR VM synchronizes only the first configured user to System Admin VM. If you delete the first user in XR VM, the
system synchronizes the next user in the root-lr group (which is the highest privilege group in XR VM for Cisco IOS XR 64-bit platforms) to System Admin VM only if there
are no other users configured in System Admin VM. The system does not automatically synchronize the subsequent users to System
Admin VM. Therefore, in earlier releases, users whose profiles did not exist in System Admin VM were not able to perform any
NETCONF or gRPC operations on System Admin VM.
From Cisco IOS XR Software Release 7.3.2, the system internally maps the users who are authorized on XR VM to System Admin
VM of the router, based on the task table of the user on XR VM. With this feature, the NETCONF and gRPC users can access admin-related
information on the router even if their user profiles do not exist on System Admin VM. By default, this feature is enabled.
User Profile Mapping from XR VM to System Admin VM
User privileges to execute commands and access data elements on the router are usually specified using certain command rules
and data rules that are created and applied on the user groups.
When the internal process for AAA starts or when you create the first user, the system creates the following set of predefined
groups, command rules and data rules in System Admin VM. These configurations are prepopulated to allow users of different
groups (such as root-system, admin-r and aaa-r) in System Admin VM
You can use the show running-configuration aaa command to view the AAA configurations.
The admin CLI for the user works based on the above configurations. The root-system is the group with the highest privilege
in System Admin VM. The admin-r group has only read and execute access to all data. The aaa-r group has access only to AAA
data. With the introduction of the admin access feature for all users, the NETCONF and gRPC applications can also access the
admin data based on the above rules and groups.
How to Allow Read Access to Administration Data for NETCONF and gRPC Clients
NETCONF and gRPC users access the administration data on the router through GET operations as defined by the respective protocols.
To allow this read access to administration data for users belonging to admin-r group, you must configure a new command rule
specifically for the NETCONF or gRPC client.
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