Accounting Methods and Targets (SRC CLI)

The available types of accounting methods for the subscriber information collector (SIC) include:

• Database—Stores accounting events in the SSR database
• Proxy—Forwards accounting events to a downstream network element that contains a proxy AAA server

You configure accounting targets by specifying the accounting method used by the SIC group. The accounting target for explicit accounting routing rules can be either the SSR database, or an AAA server in a downstream network element. The accounting target for implicit routing rules is always a proxy AAA server in a remote network element.

Using the SSR Database as the Accounting Method

You use the shared sic group identifier accounting-method accounting-method-name database statement to configure the SSR database as the accounting method. Configure this accounting method as the accounting target by using the shared sic group identifier server identifier accounting-route id target statement. In addition, you need to define the mapping between any request attributes, literals, or SIC variables, and the respective SAE plug-in attributes by using the shared sic group identifier accounting-method accounting-method-name database plug-in-attribute statement. You also need to configure the mapping between the SAE plug-in attributes and the columns in the SSR database by using the shared database cluster (primary) attribute-associations entity name field statement.

To conserve resource space in the SSR database, you can enable the remove-stopped-sessions option. When you enable this option, user session entries are deleted from the SSR database when the SIC receives an Accounting-Stop message. The corresponding service sessions are also deleted. The sequence for this is as follows:

1. The SIC receives an Accounting-Stop message from the NAS.
2. The SIC deletes the corresponding entry in the SSR user session table.
3. The SIC deletes the corresponding service session table entries.
4. The SSR notifies the SAE about the delete operation in SSR.
5. The SAE, upon receiving the delete event notification, stops the services and logs out the user.

If the remove-stopped-sessions option is not set, the following sequence occurs:

1. The SIC receives an Accounting-Stop message from the NAS.
2. The SIC updates the state of the corresponding entry in the SSR user session table to STOPPED.
3. The SSR notifies the SAE about the update operation in SSR.
4. The SAE, upon receiving the update event (state of the corresponding entry changed to STOPPED), stops the services and logs out the user.

Following is a basic working configuration for the database accounting method that includes the default configuration:

• Accounting listener—You must specify a name for the accounting listener. You can use the default port 1813.
• Device model—You can use the default model.
• Database accounting method—This is the default accounting method.
• Upstream RADIUS network element and accounting client—You must define the upstream network element and at least one accounting client.
• Accounting route—You must define the accounting route.
• Logger—You can use the default logger.

How the SIC Seamlessly Processes IP Address Changes When the SSR Database Is the Accounting Method

When a subscriber using a mobile device connects to a Wi-Fi network, the subscriber is identified by a session-id (or mac-address) within the Wi-Fi domain. The mobile device is also allocated an IP address. The subscriber logging in to the network is given access to the network. However, if the mobile device is inactive for a certain period of time, the mobile device releases the IP address and enters idle mode. When the mobile device becomes active again, it is again allocated an IP address, which is most likely not the same IP address allocated for the previous session. This IP address change also occurs when a subscriber moves between buildings within the same Wi-Fi domain. Because of the IP address change, the subscriber needs to log back in to the network, even though the session-id remains the same. However, the user is able to log in and out of the network seamlessly.

To avoid requiring the subscriber to log back in after an IP address change, the SSR tracks subscriber sessions on the basis of both the IP address and session-id. When the SIC receives an accounting message that includes the new IP address and the initial session-id, it removes the record with the old IP address from the SSR database and inserts the record with the new IP address. To use this capability, you must map a unique value such as MAC-Address or IMSI to the Session ID column in the subscriber sessions table.

Mapping Attributes When Using the Database Accounting Method

When you use the SSR database as the accounting method, you need to define the mapping between:

• SIC request attributes and variables and SAE plug-in attributes
• SAE plug-in attributes and fields in the subscriber sessions table in the SSR database

The SIC uses internal variables to store intermediate results of transaction processing, such as editing. Every variable must have a name and a value. You can define variables while configuring editing rules. If a variable is configured in an editing rule and it does not already exist, it is created. Another place where variables are used is in the mapping between the SIC, SAE plug-in attributes, and the fields in the subscriber sessions table in the SSR database. A variable from an editing rule can be used in the mapping, which allows you to store the value of the variable (the result of the editing process) in the subscriber sessions table field. There are some internal SIC variables such as:

• ReceiveTime—This is the timestamp of the accounting event.
• UserStatusType—This is correlated to the RADIUS Acct-Status-Type: 1 for Accounting-Start, 2 for Accounting-Stop.

Note: You must configure the SIC group to use the database accounting method. In addition, you must map any fields in the SSR subscriber sessions table that have a not-null requirement to either a request attribute or SIC variable.

The following output shows the attribute mapping between SAE plug-in attributes and the SIC request attributes and variables:

plug-in-attribute id="PA_USER_INET_ADDRESS" request-attribute="NAS-IP-Address"
plug-in-attribute id="PA_LOGIN_NAME" request-attribute="User-Name"
plug-in-attribute id="PA_PROPERTY.session-id" variable="ReceiveTime"

The following output shows the mapping between SAE plug-in attributes and the fields in the subscriber sessions table in the SSR database:

ssrMapping
table name="SubscriberSessions"
attributeMapping attribute="PA_USER_INET_ADDRESS" field="UserIPAddress" 
attributeMapping attribute="PA_LOGIN_NAME" field="UserName" 
 attributeMapping attribute="PA_PROPERTY.session-id" field="Sessionid" 
 table
 ssrMapping

This mapping results in attributes and variables mapped as shown in Table 26.

Using the Proxy RADIUS Accounting Method

The proxy RADIUS accounting method forwards accounting events to an accounting target (AAA server) located in a downstream network element. You use the shared sic group identifier accounting-method accounting-method-name proxy radius statement to configure a proxy RADIUS accounting method as the accounting method. You configure the downstream network element that contains the AAA server by using the shared sic group identifier radius network-element id downstream statement. You configure the AAA server as the accounting target by using the shared sic group identifier radius network-element id downstream accounting-target statement.

Following is a basic working configuration for the proxy accounting method that includes the default configuration:

• Accounting listener—You must specify a name for the accounting listener. You can use the default port 1813.
• Device model—You can use the default model.
• Proxy accounting method—You must configure the proxy accounting method.
• Outbound transport—You can use the default outbound transport.
• Upstream RADIUS network element and accounting client—You must define the upstream network element and at least one accounting client.
• Downstream RADIUS network element and accounting target—You must define the downstream network element and the accounting target.
• Accounting route—You must define the accounting route.
• Logger—You can use the default logger.

Related Documentation

• Configuring the SSR Database as the Accounting Method (SRC CLI)
• Configuring Proxy RADIUS as the Accounting Method (SRC CLI)
• Request Routing (SRC CLI)
• Configuring Downstream Network Elements and Accounting and Authentication Targets (SRC CLI)
• Configuring the Optional Editing Rules Used by the SIC Group (SRC CLI)