Identity-Based Networking Services Configuration Guide, Cisco IOS XE Release 3SE (Cisco WLC 5700 Series)
Change of Authorization Support
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Change of Authorization Support

Change of Authorization Support

Identity-Based Networking Services supports RADIUS change of authorization (CoA) commands for session query, reauthentication, and termination, port bounce and port shutdown, and service template activation and deactivation. This module provides information about the supported CoA commands for Identity-Based Networking Services.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

Information About CoA Support

RADIUS Change-of-Authorization Support

Cisco IOS software supports the RADIUS CoA extensions defined in RFC 5176 that are typically used in a push model to allow the dynamic reconfiguring of sessions from external AAA or policy servers. Per-session CoA requests are supported for session identification, session termination, host reauthentication, port shutdown, and port bounce. This model comprises one request (CoA-Request) and two possible response codes:

  • CoA acknowledgement (ACK) [CoA-ACK]
  • CoA nonacknowledgement (NAK) [CoA-NAK]

The request is initiated from a CoA client (typically a AAA or policy server) and directed to the device that acts as a listener.

The table below shows the RADIUS CoA commands and vendor-specific attributes (VSAs) supported by Identity-Based Networking Services. All CoA commands must include the session identifier between the device and the CoA client.

Table 1 RADIUS CoA Commands Supported by Identity-Based Networking Services

CoA Command

Cisco VSA

Activate service

Cisco:Avpair=“subscriber:command=activate-service”

Cisco:Avpair=“subscriber:service-name=<service-name>”

Cisco:Avpair=“subscriber:precedence=<precedence-number>”

Cisco:Avpair=“subscriber:activation-mode=replace-all”

Deactivate service

Cisco:Avpair=“subscriber:command=deactivate-service”

Cisco:Avpair=“subscriber:service-name=<service-name>”

Bounce host port

Cisco:Avpair=“subscriber:command=bounce-host-port”

Disable host port

Cisco:Avpair=“subscriber:command=disable-host-port”

Session query

Cisco:Avpair=“subscriber:command=session-query”

Session reauthenticate

Cisco:Avpair=“subscriber:command=reauthenticate”

Cisco:Avpair=“subscriber:reauthenticate-type=last” or

Cisco:Avpair=“subscriber:reauthenticate-type=rerun”

Session terminate

This is a standard disconnect request and does not require a VSA.

Session Identification

For disconnect and CoA requests targeted at a particular session, the device locates the session based on one or more of the following attributes:

  • Acct-Session-Id (IETF attribute #44)
  • Audit-Session-Id (Cisco VSA)
  • Calling-Station-Id (IETF attribute #31, which contains the host MAC address)
  • IPv6 Attributes, which can be one of the following:
    • Framed-IPv6-Prefix (IETF attribute #97) and Framed-Interface-Id (IETF attribute #96), which together create a full IPv6 address per RFC 3162
    • Framed-IPv6-Address
  • Plain IP Address (IETF attribute #8)

If more than one session identification attribute is included in the message, all of the attributes must match the session or the device returns a Disconnect-NAK or CoA-NAK with the error code “Invalid Attribute Value.”

For CoA requests targeted at a particular enforcement policy, the device returns a CoA-NAK with the error code “Invalid Attribute Value” if any of the above session identification attributes are included in the message.

CoA Activate Service Command

The CoA activate service command can be used to activate a service template on a session. The AAA server sends the request in a standard CoA-Request message using the following VSAs:

Cisco:Avpair=“subscriber:command=activate-service”

Cisco:Avpair=“subscriber:service-name=<service-name>”

Cisco:Avpair=“subscriber:precedence=<precedence-number>”

Cisco:Avpair=“subscriber:activation-mode=replace-all”

Because this command is session-oriented, it must be accompanied by one or more of the session identification attributes described in the “Session Identification” section. If the device cannot locate a session, it returns a CoA-NAK message with the “Session Context Not Found” error-code attribute. If the device locates a session, it initiates an activate template operation for the hosting port and a CoA-ACK is returned. If activating the template fails, a CoA-NAK message is returned with the Error-Code attribute set to the appropriate message.

If the device fails before returning a CoA-ACK to the client, the process is repeated on the new active device when the request is re-sent from the client. If the device fails after returning a CoA-ACK message to the client but before the operation is complete, the operation is restarted on the new active device.

CoA Deactivate Service Command

The CoA deactivate service command can be used to deactivate a service template on a session. The AAA server sends the request in a standard CoA-Request message using the following VSAs:

Cisco:Avpair=“subscriber:command=deactivate-service”

Cisco:Avpair=“subscriber:service-name=<service-name>”

Because this command is session-oriented, it must be accompanied by one or more of the session identification attributes described in the “Session Identification” section. If the device cannot locate a session, it returns a CoA-NAK message with the “Session Context Not Found” error-code attribute. If the device locates a session, it initiates a deactivate template operation for the hosting port and a CoA-ACK is returned. If deactivating the template fails, a CoA-NAK message is returned with the Error-Code attribute set to the appropriate message.

If the device fails before returning a CoA-ACK to the client, the process is repeated on the new active device when the request is re-sent from the client. If the device fails after returning a CoA-ACK message to the client but before the operation is complete, the operation is restarted on the new active device.

CoA Bounce Host Port Command

The CoA bounce host port command terminates a session and bounces the port (initiates a link down event followed by a link up event). The AAA server sends the request in a standard CoA-Request message with the following VSA:

Cisco:Avpair=“subscriber:command=bounce-host-port”

Because this command is session-oriented, it must be accompanied by one or more of the session identification attributes described in the “Session Identification” section. If the session cannot be located, the device returns a CoA-NAK message with the “Session Context Not Found” error-code attribute. If the session is located, the device disables the hosting port for a period of ten seconds, reenables it (port bounce), and returns a CoA-ACK.

If the device fails before returning a CoA-ACK to the client, the process is repeated on the new active device when the request is re-sent from the client. If the device fails after returning a CoA-ACK message to the client but before the operation is complete, the operation is restarted on the new active device.

The CoA bounce port command is useful as a last resort when an endpoint needs to acquire a new IP address after a change in authorization and this is the only way to indicate to the endpoint to restart the DHCP process. This can occur when there is a VLAN change and the endpoint is a device, such as a printer, that does not have a mechanism to detect a change on this authentication port. This command can cause a link flap on an authentication port, which triggers DHCP renegotiation from one or more hosts connected to this port.

CoA Disable Host Port Command

The CoA disable host port command administratively shuts down the authentication port that is hosting a session, which terminates the session. The AAA server sends the request in a standard CoA-Request message with the following VSA:

Cisco:Avpair=“subscriber:command=disable-host-port”

Because this command is session-oriented, it must be accompanied by one or more of the session identification attributes described in the “Session Identification” section. If the device cannot locate the session, it returns a CoA-NAK message with the “Session Context Not Found” error-code attribute. If the device locates the session, it disables the hosting port and returns a CoA-ACK message.

If the device fails before returning a CoA-ACK to the client, the process is repeated on the new active device when the request is re-sent from the client. If the device fails after returning a CoA-ACK message to the client but before the operation is complete, the operation is restarted on the new active device.

CoA Session Query Command

The CoA session query command requests service information about a subscriber session. The AAA server sends the request in a standard CoA-Request message containing the following VSA:

Cisco:Avpair=“subscriber:command=session-query”

Because this command is session-oriented, it must be accompanied by one or more of the session identification attributes described in the “Session Identification” section. If the device cannot locate a session, it returns a CoA-NAK message with the “Session Context Not Found” error-code attribute. If the device locates a session, it performs a session query operation on the session and returns a CoA-ACK message.

If the device fails before returning a CoA-ACK to the client, the process is repeated on the new active device when the request is re-sent from the client. If the device fails after returning a CoA-ACK message to the client but before the operation is complete, the operation is restarted on the new active device.

CoA Session Reauthenticate Command

To initiate session authentication, the AAA server sends a standard CoA-Request message containing the following VSAs:

Cisco:Avpair=“subscriber:command=reauthenticate”

Cisco:Avpair=“subscriber:reauthenticate-type=<last | rerun>”

“reauthenticate-type” defines whether the CoA reauthentication request uses the authentication method that last succeeded on the session or whether the authentication process is completely rerun.

The following rules apply:

  • “subscriber:command=reauthenticate” must be present to trigger a reauthentication.
  • If “subscriber:reauthenticate-type” is not specified, the default behavior is to rerun the last successful authentication method for the session. If the method reauthenticates successfully, all old authorization data is replaced with the new reauthenticated authorization data.
  • “subscriber:reauthenticate-type” is valid only when included with “subscriber:command=reauthenticate.” If it is included in another CoA command, the VSA will be silently ignored.

If the device fails before returning a CoA-ACK to the client, the process is repeated on the new active device when the request is resent from the client. If the device fails after returning a CoA-ACK message to the client but before the operation is complete, the operation is restarted on the new active device.

CoA Session Terminate Command

A CoA Disconnect-Request command terminates a session without disabling the host port. This command causes reinitialization of the authenticator state machine for the specified host, but does not restrict the host’s access to the network. If the session cannot be located, the device returns a Disconnect-NAK message with the “Session Context Not Found” error-code attribute. If the session is located, the device terminates the session. After the session has been completely removed, the device returns a Disconnect-ACK.

If the device fails before returning a CoA-ACK to the client, the process is repeated on the new active device when the request is re-sent from the client.

To restrict a host’s access to the network, use a CoA Request with the Cisco:Avpair=“subscriber:command=disable-host-port” VSA. This command is useful when a host is known to cause problems on the network and network access needs to be immediately blocked for the host. When you want to restore network access on the port, reenable it using a non-RADIUS mechanism.

Additional References

Related Documents

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Command List, All Releases

Identity-Based Networking Services commands

Cisco IOS Identity-Based Networking Services Command Reference

Address Resolution Protocol (ARP) commands

Cisco IOS IP Addressing Services Command Reference

ARP configuration tasks

IP Addressing - ARP Configuration Guide

Authentication, authorization, and accounting (AAA) configuration tasks

Authentication Authorization and Accounting Configuration Guide

AAA commands

Cisco IOS Security Command Reference

Standards and RFCs

Standard/RFC

Title

RFC 5176

Dynamic Authorization Extensions to RADIUS

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

http:/​/​www.cisco.com/​cisco/​web/​support/​index.html

Feature Information for CoA Support

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

Table 2 Feature Information for CoA Support

Feature Name

Releases

Feature Information

Change of Authorization

Cisco IOS XE Release 3.2SE

Supports CoA requests for initiating the following:

  • Activating and deactivating service templates on sessions
  • Port bounce
  • Port shutdown
  • Querying a session
  • Reauthenticating a session
  • Terminating a session

These VSAs are sent in a standard CoA-Request message from a AAA server.