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 XE router to the RADIUS server.
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest feature information and caveats, see 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 document.
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 XE 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.
Summary
- 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 | |||
|---|---|---|---|---|
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Example: Router> enable |
Enables privileged EXEC mode.
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Example: Router# configure terminal |
Enters global configuration mode. |
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Example: Router(config)# aaa group server radius myservergroup |
Enters server-group configuration mode. |
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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:
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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.
Related Documents
| Related Topic |
Document Title |
|---|---|
| Security features |
Cisco IOS XE Security Configuration Guide: Securing User Services, Release 2 |
| Security commands |
Cisco IOS Security Command Reference |
Standards
| Standard |
Title |
|---|---|
| No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature. |
-- |
MIBs
| MIB |
MIBs Link |
|---|---|
| No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature. |
To locate and download MIBs for selected platforms, Cisco IOS XE software releases, and feature sets, use Cisco MIB Locator found at the following URL: |
RFCs
| RFC |
Title |
|---|---|
| No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature. |
-- |
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 |
Cisco IOS XE Release 2.1 |
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 XE router to the RADIUS server. In Cisco IOS XE Release 2.1, this feature was introduced on Cisco ASR 1000 Series Aggregation Services Routers. The following commands were introduced or modified by this feature: radius-server throttle, throttle |
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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.
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