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Contents
- Throttling of AAA RADIUS Records
- Finding Feature Information
- Information About Throttling of AAA RADIUS Records
- Benefits of the Throttling of AAA RADIUS Records Feature
- Throttling Access Requests and Accounting Records
- How to Configure Throttling of AAA RADIUS Records
- Throttling Accounting and Access Request Packets Globally
- Throttling Accounting and Access Request Packets Per Server Group
- Configuration Examples for Throttling of AAA RADIUS Records
- Throttling Accounting and Access Request Packets Globally Example
- Throttling Accounting and Access Request Packets Per Server Group Example
- Additional References
- Feature Information for Throttling of AAA RADIUS Records
Throttling of AAA RADIUS Records
The Throttling of AAA (RADIUS) Records feature supports throttling of access (authentication and authorization) and accounting records that are sent to the RADIUS server. This feature allows a user to configure the appropriate throttling rate to avoid network congestion and instability; such as when there is insufficient bandwidth to accommodate a sudden burst of records generated from the Cisco IOS router to the RADIUS server.
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 Throttling of AAA RADIUS Records
- Benefits of the Throttling of AAA RADIUS Records Feature
- Throttling Access Requests and Accounting Records
Benefits of the Throttling of AAA RADIUS Records Feature
A Network Access Server (NAS), acting as RADIUS client, can generate a burst of accounting or access requests, causing severe network congestion or causing the RADIUS server to become overloaded with a burst of RADIUS traffic. This problem could be compounded when multiple NASs interact with the RADIUS servers.
The following conditions can trigger a sudden burst of RADIUS traffic:
- An interface flap, which in turn brings down all the subscriber sessions and generates accounting requests for each subscriber.
- The Cisco IOS High Availability (HA) program generating a START record for every session that survived a switchover, such as the scenario described the preceding bullet.
A large number of generated requests can make the network unstable if there is insufficient bandwidth or if the RADIUS server is slow to respond. Neither the User Datagram Protocol (UDP) transport layer nor the RADIUS protocol has a flow control mechanism. The throttling mechanism provided by this feature provides a solution for these issues.
Throttling Access Requests and Accounting Records
The Throttling of AAA (RADIUS) Records feature introduces a mechanism to control packets (flow control) at the NAS level, which improves the RADIUS server performance.
Because of their specific uses, access requests and accounting records must be treated separately. Access request packets are time sensitive, while accounting record packets are not.
- If a response to an access request is not returned to the client in a timely manner, the protocol or the user will time out, impacting the device transmission rates.
- Accounting records packets are not real-time critical.
When configuring threshold values on the same server, it is important to prioritize threshold values for the handling of the time-sensitive access request packets and to place a lesser threshold value on the accounting records packets.
In some cases, when an Internet Service Provider (ISP) is using separate RADIUS servers for access requests and accounting records, only accounting records throttling may be required.
- The Throttling of AAA (RADIUS) Records is disabled, by default.
- Throttling functionality can be configured globally or at server group level.
How to Configure Throttling of AAA RADIUS Records
This section describes how to configure throttling of access (authentication and authorization) and accounting records that are sent to the RADIUS server for both, global and server groups.
Server-group configurations are used to enable or disable throttling for a particular server group and to specify the threshold value for that server group.
 Note | Server-group configurations override any configured global configurations. |
- Throttling Accounting and Access Request Packets Globally
- Throttling Accounting and Access Request Packets Per Server Group
Throttling Accounting and Access Request Packets Globally
To globally configure the throttling of accounting and access request packets, perform the following task.
DETAILED STEPS
Throttling Accounting and Access Request Packets Per Server Group
The following server-group configuration can be used to enable or disable throttling for a specified server group and to specify the threshold value for that server group.
To configure throttling of server-group accounting and access request packets, perform the following task.
DETAILED STEPS
| Command or Action | Purpose | |||
|---|---|---|---|---|
Step 1 |
enable
Example: Router> enable |
Enables privileged EXEC mode.
| ||
Step 2 |
configure
terminal
Example: Router# configure terminal |
Enters global configuration mode. | ||
Step 3 |
aaa
group
server
radius
server-group-name
Example: Router(config)# aaa group server radius myservergroup |
Enters server-group configuration mode. | ||
Step 4 |
throttle
{[accounting threshold] [access threshold [access-timeout number-of-timeouts]]} Example: Router(config-sg-radius)# throttle accounting 100 access 200 access-timeout 2 |
Configures the specified server-group throttling values for accounting and access request packets. For this example:
| ||
Step 5 |
exit
Example: Router(config-sg-radius)# exit |
Exits server-group configuration mode. |
Configuration Examples for Throttling of AAA RADIUS Records
- Throttling Accounting and Access Request Packets Globally Example
- Throttling Accounting and Access Request Packets Per Server Group Example
Throttling Accounting and Access Request Packets Globally Example
The following example shows how to limit the number of accounting requests sent to a server to 100:
enable configure terminal radius-server throttle accounting 100
The following example shows how to limit the number of access requests packets sent to a server to 200 and sets the number of time-outs allowed per transactions to 2:
enable configure terminal radius-server throttle access 200 radius-server throttle access 200 access-timeout 2
The following example shows how to throttle both accounting and access request packets:
enable configure terminal radius-server throttle accounting 100 access 200
Throttling Accounting and Access Request Packets Per Server Group Example
The following example shows how to limit the number of accounting requests sent to server-group-A to 100:
enable configure terminal aaa group server radius server-group-A throttle accounting 100
The following example shows how to limit the number of access requests packets sent to server-group-A to 200 and sets the number of time-outs allowed per transactions to 2:
enable configure terminal aaa group server radius server-group-A throttle access 200 access-timeout 2
The following example shows how to throttle both accounting and access request packets for server-group-A:
enable configure terminal aaa group server radius server-group-A throttle accounting 100 access 200
Additional References
The following sections provide references related to the Throttling of AAA (RADIUS) Records feature.
MIBs
Technical Assistance
|
Description |
Link |
|---|---|
|
The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies. To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds. Access to most tools on the Cisco Support website requires a Cisco.com user ID and password. |
Feature Information for Throttling of AAA RADIUS Records
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 1 | Feature Information for Throttling of AAA (RADIUS) Records |
|
Feature Name |
Releases |
Feature Information |
|---|---|---|
|
Throttling of AAA (RADIUS) Records |
12.2(33)SRC 12.4(20)T |
The Throttling of AAA (RADIUS) Records feature supports throttling of access (authentication and authorization) and accounting records that are sent to the RADIUS server. This feature allows a user to configure the appropriate throttling rate to avoid network congestion and instability; such as when there is insufficient bandwidth to accommodate a sudden burst of records generated from the Cisco IOS router to the RADIUS server. In Release 12.2(33)SRC, this feature was introduced on the Cisco 7200 and Cisco 7200 routers. The following commands were introduced or modified by this feature: radius-server throttle, throttle |
Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks. Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)
Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.