- Overview
- Using the Graphical User Interface
- RADIUS Accounting
- Diameter
- Extensible Authentication Protocols
- Using Replication
- Using Identity Caching
- Using Prepaid Billing
- Using Cisco Prime Access Registrar Server Features
- Directing RADIUS Requests
- Using FastRules to Process Packet Flow
- Using LDAP
- Using Open Database Connectivity
- SIGTRAN-M3UA
- Using SNMP
- Backing Up the Database
Using Prepaid Billing
Cisco Prime Access Registrar (Prime Access Registrar) supports two types of prepaid billing, IS835C and Cisco Real-time Billing (CRB), a Cisco proprietary solution. The IS835C version adheres to industry standards and is the preferred version.
Three components are required to support a prepaid billing service, such as the following:
The most important factor for an effective prepaid billing service is in developing a shared library to be configured under the prepaid RemoteServer object. The shared library should be developed to implement all specified API functions. You will have to provide a shared library that meets the needs of your environment. The shared library must implement the API functions to perform the various tasks required for your specific implementation of the prepaid billing service.
Note
Cisco works with you to develop the prepaid billing service and implement the API. For more information, contact your Cisco systems engineer.
Overview
When a subscriber uses a prepaid billing service, each call requires a set of data about the subscriber. However, the AAA network has no previous knowledge of the subscriber’s usage behavior. Prime Access Registrar uses an iterative authorization paradigm over multiple sessions to support the prepaid billing solution.
Each time an authorization request is made, the billing server apportions a fraction of the subscriber’s balance into a quota. When a subscriber uses multiple sessions, each session must obtain its own quota. When a previously allocated quota is depleted, a session must be reauthorized to obtain a new quota.
Note The granularity and the magnitude of the quota is in the design and implementation of the prepaid billing server and is beyond the scope of this document. In general, a smaller quota generates more network traffic, but allows more sessions per subscriber. When the quota is equal to a subscriber’s total account balance, there is minimal network traffic, but only one session can be supported.
When a subscriber’s current quota is depleted, the AAA client initiates a reauthorization request sending Access-Request packets. After the Prime Access Registrar server receives the request, it forwards the request to the billing server. The billing server then returns the next quota to use. The new quota might not be the same as the previous, and the billing server might adjust the quota dynamically.
IS835C Prepaid Billing
Prime Access Registrar acts as a RADIUS protocol head for all the requirements specified in the cdma2000 Wireless IP Network Standard: PrePaid Packet Data Service specification:
https://www.3gpp2.org/Public_html/Specs/X.S0011-006-C_v3.0_061030.pdf
As long as the prepaid client understands or accepts what the external billing server sends, the service should work. The Prime Access Registrar server neither imposes nor is affected by the values of attributes returned from the external billing server.
For additional information, see cdma2000 Wireless IP Network Standard: Accounting Services and 3GPP2 RADIUS VSAs at the following URL:
https://www.3gpp2.org/Public_html/Specs/X.S0011-005-C_v3.0_061030.pdf
The IS835C specification requires that the Prime Access Registrar server be able to determine that a particular user is a prepaid billing user. A user is accepted as a valid prepaid user when the response dictionary of the incoming packet contains the Prime Access Registrar internal subattribute named prepaid.
The IS835C specification requires prepaid users to first be authenticated by the RADIUS server. This requires the configuration of a group service with an authentication service first, followed by the prepaid service that adds prepaid attributes as shown in Setting Up an Authentication Group Service. The group service configuration enables the AA service to add the prepaid subattribute to the response dictionary upon successful authentication, before the prepaid service is invoked.
Configuring IS835C Prepaid Billing
To configure an IS835C prepaid billing service, use the following sections to configure the required Prime Access Registrar objects:
Setting Up a Prepaid Billing RemoteServer
Prime Access Registrar loads the library dynamically and registers the API functions, then calls out the library initialization API once at startup. The call to initialize functions initializes various data structures and connections with the billing server, as required.
Table 8-1 lists and describes the properties required for an IS835C RemoteServer object.
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Name of the shared library provided by the billing server vendor, such as libprepaid.so |
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Number of threads the prepaid service and billing server can each use (default is 8). |
Setting Up a Prepaid Billing Remote Server
To set up a prepaid billing remote server:
Step 1 Use aregcmd to add a RemoteServer under /Radius/RemoteServers.
Step 2 Set remoteserver protocol to prepaid-is835c.
The following is the default configuration of a prepaid-is835c RemoteServer.
Setting Up an IS835C Prepaid Service
Prime Access Registrar uses a service type prepaid to support the prepaid billing solution. The prepaid service mediates between the client NAS and the external prepaid billing server.
Setting Up an IS835C Prepaid Service
To set up an IS835C prepaid service:
Step 1 Use aregcmd to add a prepaid service under /Radius/Services :
Step 2 Set the service type to prepaid.
A prepaid service has the following default properties:
Step 3 Add a reference to the is835c-prepaid RemoteServer.
Setting Up Local Authentication
If you use the Prime Access Registrar server for authentication and authorization in your prepaid billing solution, you should configure an AA service. For example, you might configure a service similar to local-users (in the example configuration) for authentication and authorization of local users.
If some of the users are non-prepaid users or if the prepaid users need to have RADIUS authorization attributes returned, you should configure an AA service to perform that authentication and authorization.
Setting Up a Local Authentication
To set up a local authentication:
Step 1 Use aregcmd to set up a local authentication service.
add Prepaid-LocalAuthentication
cd prepaid-LocalAuthentication
Step 2 Set the service type to local.
Step 3 Set the UserList property to the userlist that contains IS835C prepaid users.
Note You can use an LDAP or ODBC service in place of the local authentication service.
The authentication service must add the Prime Access Registrar internal attribute prepaid (subattribute 22) to the response upon successful authentication.
Setting Up an Authentication Group Service
Your prepaid billing solution usually requires a group service to tie together an AA service with a prepaid service, a group service to tie together an accounting service with a prepaid service, or both.
If you are using an AA service with your prepaid billing solution, you must configure a group service, for example prepaid-users, that ties the requests to the AA service (local-users in our example) with the prepaid service.
If you are using Prime Access Registrar for an accounting service with your prepaid billing solution, you must configure a group service, for example prepaid-file, that ties accounting requests to both the regular accounting service (local-file in our example) and the prepaid service.
Setting Up an Authentication Group Service
To set up an authentication group service:
Step 1 Use aregcmd to add a prepaid authentication group service under /Radius/Services.
add prepaid-groupAuthentication
cd prepaid-groupAuthentication
Step 2 Set the service type to group.
The group service requires the ResultRule to be set to AND, the default setting for a group service.
Step 3 Change directory to GroupServices and add references to the prepaid service and the authentication service.
add 1 Prepaid-LocalAuthentication
CRB Prepaid Billing
Cisco Real-Time Billing (CRB) is a Cisco proprietary method of providing prepaid billing service. Prime Access Registrar uses vendor-specific attributes (VSA) to extend the standard RADIUS protocol to carry information not usually present in the standard RADIUS packet. Prime Access Registrar uses a set of VSAs allocated to the Cisco VSA pool [26,9].
Prime Access Registrar required several different types of measurements to support a prepaid billing solution. These measurements require the use of metering variables to perform usage accounting. Table 8-2 lists the different measurements and what the AAA client, Prime Access Registrar server, and billing server do with them.
Prime Access Registrar provides maximum flexibility to billing servers by allowing the metering variable to be modified as the service is used. This requires network nodes to measure all parameters all the time, but to report values only after receiving a reauthorization request.
Note If you have been using an earlier implementation of CRB prepaid billing (Cisco Access Registrar 3.5.2 or earlier), you must recompile the API implementation with the newer API due to the addition of the parameter ebs_context as the first parameter to all API methods. Contact your Cisco systems engineer for assistance with the new API.
This section contains the following topics:
- Configuring CRB Prepaid Billing
- Configuring CRB Prepaid Billing for SSG
- Generic Call Flow
- Vendor-Specific Attributes
Configuring CRB Prepaid Billing
To configure an CRB prepaid billing service, use the following sections to configure the required Prime Access Registrar objects:
- Setting Up a Prepaid Billing RemoteServer
- Setting Up a CRB Prepaid Service
- Setting Up a Local Accounting Service
- Setting Up a Local Authentication Service
- Setting Up a Prepaid Accounting Group Service
- Setting Up an Authentication Group Service
If you are using CRB prepaid billing with Service Selection Gateway (SSG), you must also configure extension point scripts and prepaid clients. See Configuring CRB Prepaid Billing for SSG.
Setting Up a Prepaid Billing RemoteServer
Table 8-3 lists and describes the properties required for an CRB RemoteServer object.
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Name of the shared library provided by the billing server vendor, such as libprepaid.so |
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Number of threads the prepaid service and billing server can each use (default is 8). |
Setting Up a Prepaid Billing Remote Server
To set up a prepaid billing remote server:
Step 1 Use aregcmd to add a RemoteServer under /Radius/RemoteServers.
Step 2 Set the RemoteServer protocol to prepaid-crb.
The following is the default configuration of a prepaid-crb RemoteServer.
Setting Up a CRB Prepaid Service
Prime Access Registrar uses a service type prepaid to support the prepaid billing solution. The prepaid service mediates between the client NAS and the external prepaid billing server.
The prepaid service must receive accounting requests to accurately charge the prepaid billing user. You can also set the prepaid service in a group service to log accounting requests locally or to proxy the accounting requests to another service or to both locations.
Setting Up a CRB Prepaid Service
To set up a CRB prepaid service:
Step 1 Use aregcmd to add a prepaid service under /Radius/Services :
Step 2 Set the service type to prepaid.
A prepaid service has the following default properties:
Step 3 Add a reference to the prepaid-crb RemoteServer.
Note The following steps are required only when using Prepaid-CRB with SSG.
Step 4 Set the IncomingScript to IncomingScript PPI-Parse-Prepaid-Incoming.
set IncomingScript PPI-Parse-Prepaid-Incoming
Step 5 Set the OutgoingScript to PPO-Parse-Prepaid-Outgoing.
set OutgoingScript PPO-Parse-Prepaid-Outgoing
Setting Up a Local Accounting Service
If you want to use the Prime Access Registrar server to record the accounting records locally or to forward the accounting records to another RADIUS server, you must configure an accounting service. You might configure a service similar to local-file (in the example configuration) for accounting requests. Accounting requests can be logged locally (with an accounting service) or remotely (with a RADIUS service).
If you use the prepaid billing server to generate the accounting records, an accounting service is not necessary.
Setting Up a Local Accounting Service
To set up a local accounting service:
Step 1 Use aregcmd to add a local accounting service under /Radius/Services.
add prepaid-LocalFileAccounting
Step 2 Set the service type to file.
cd prepaid-LocalFileAccounting
The file type service has the following properties:
Step 3 Set the FilenamePrefix to Prepaid-Accounting.
set FilenamePrefix Prepaid-Accounting
Step 4 Set the MaxFileAge to one hour.
The MaxFileSize should remain at the default value of 10 megabytes.
Step 5 Set UseLocalTimeZone to TRUE.
Setting Up a Local Authentication Service
If you use the Prime Access Registrar server for authentication and authorization in your prepaid billing solution, you should configure an AA service. For example, you might configure a service similar to local-users (in the example configuration) for authentication and authorization of local users.
If some of the users are non-prepaid users or if the prepaid users need to have RADIUS authorization attributes returned, you should configure an AA service to perform that authentication and authorization.
If all of the users in a realm are prepaid users and the prepaid billing client does not require normal RADIUS authorization attributes, an AA service is not necessary.
Setting Up a Local Authentication Service
To set up a local authentication service:
Step 1 Use aregcmd to set up a local authentication service.
add Prepaid-LocalAuthentication
cd prepaid-LocalAuthentication
Step 2 Set the service type to local.
Step 3 Set the UserList property to the userlist that contains IS835C prepaid users.
Note You can use an LDAP or ODBC service in place of the local authentication service.
Setting Up a Prepaid Accounting Group Service
A prepaid billing solution usually requires a group service to tie together an AA service with a prepaid service, a group service to tie together an accounting service with a prepaid service, or both.
If you are using an AA service with your prepaid billing solution, you must configure a group service, for example prepaid-users, that ties the requests to the AA service (local-users in our example) with the prepaid service.
If you are using Prime Access Registrar for an accounting service with your prepaid billing solution, you must configure a group service, for example prepaid-file, that ties accounting requests to both the regular accounting service (local-file in our example) and the prepaid service.
Setting Up a Prepaid Accounting Group Service
To set up a prepaid accounting group service:
Step 1 Use aregcmd to create an accounting group service under /Radius/Services.
Step 2 Set the service type to group.
The group service has the following properties:
Step 3 Reference the Prepaid and Prepaid-LocalAccounting services under GroupServices.
add 2 prepaid-LocalFileAccounting
Setting Up an Authentication Group Service
A prepaid billing solution usually requires a group service to tie together an AA service with a prepaid service, a group service to tie together an accounting service with a prepaid service, or both.
If you are using an AA service with your prepaid billing solution, you must configure a group service, for example prepaid-users, that ties the requests to the AA service with the prepaid service.
If you are using Prime Access Registrar for an accounting service with your prepaid billing solution, you must configure a group service, for example prepaid-file, that ties accounting requests to both the regular accounting service and the prepaid service.
Setting Up an Authentication Group Service
To set up an authentication group service:
Step 1 Use aregcmd to add a prepaid authentication group service under /Radius/Services.
add prepaid-groupAuthentication
cd group-prepaidAuthentication
Step 2 Set the service type to group.
The group service requires the ResultRule to be set to AND, the default setting for a group service.
Step 3 Change directory to GroupServices and add references to the prepaid service and the authentication service.
add 1 Prepaid-LocalAuthentication
Configuring CRB Prepaid Billing for SSG
In addition to the configuration described in CRB Prepaid Billing, when using CRB-Prepaid billing with SSG, you must also perform the following:
- Setting Up an Outgoing Script
- Setting Up an Incoming Script
- Setting Up a Prepaid Outgoing Script
- Adding Prepaid Clients
Step 1 Use aregcmd to add the PCO-Parse-Client-Outgoing outgoing script under /Radius/Scripts:
Step 2 Set the language to tcl.
Step 3 Set the filename to PCO-parse.client-outgoing.tcl.
set filename PCO-parse.client-outgoing.tcl
Step 4 Set the EntryPoint to PCO-parse-client-outgoing.
set EntryPoint PCO-parse-client-outgoing
Step 1 Use aregcmd to add the PPI-Parse-Prepaid-Incoming script under /Radius/Scripts.
add PPI-Parse-Prepaid-Incoming
Step 2 Set the language to tcl.
Step 3 Set the filename to PPI-Parse-Prepaid-Incoming.tcl.
set filename PPI-Parse-Prepaid-Incoming.tcl
Step 4 Set the EntryPoint to PPO-Parse-Prepaid-Outgoing.
set EntryPoint PPO-Parse-Prepaid-Outgoing
Setting Up a Prepaid Outgoing Script
To set up a prepaid outgoing script:
Step 1 Use aregcmd to add the PPO-Parse-Prepaid-Outgoing outgoing script under /Radius/Scripts:
Step 2 Add the PPO-Parse-Prepaid-Outgoing outgoing script under /Radius/Scripts.
add PPO-Parse-Prepaid-Outgoing
Step 3 Set the language to tcl.
Step 4 Set the filename to PPO-Parse-Prepaid-Outgoing.tcl.
set filename PPO-Parse-Prepaid-Outgoing.tcl
Step 5 Set the EntryPoint to PPO-Parse-Prepaid-Outgoing.
set EntryPoint PPO-Parse-Prepaid-Outgoing
Step 1 Use aregcmd to add the prepaid clients under /Radius/Clients.
A RADIUS client has the following properties:
Step 2 Set the IPAddress property to the client IP address.
Step 4 Set the to PCO-Parse-Client-Outgoing.
set out PCO-Parse-Client-Outgoing
Generic Call Flow
This section describes the generic call flow for the Prime Access Registrar CRB prepaid billing. The call flow is controlled by the AAA client. The Prime Access Registrar server converts VSAs into calls to the billing server. For information about call flows and attributes for IS835C, see IS835C Prepaid Billing.
The packet flows presented in Figure 8-1 are specific to the Prime Access Registrar CRB prepaid billing only. The headlines in the packet flows are general and do represent all data transferred. The letters c, s, and b in Figure 8-1 designate the packet’s source of client, server, or billing server, respectively.
Figure 8-1 Generic Call Flow Diagram
Access-Request (Authentication)
Flow 1c shows the client sending the Access-Request to AAA Server, part of a normal authentication request. The exact nature of the message contents is dictated by the access technology, be it be CDMA1X-RTT, GPRS, or another. The Access-Request might involve other messages such as PAP/CHAP or another form of authentication.
The Flow 1c Access-Request might contain a prepaid specific VSA, CRB_AUTH_REASON. Table 8-4 lists the attributes included in the authentication Access-Request. This tells the Prime Access Registrar server to authenticate the subscriber with the Prepaid server as well. If the value is CRB_AR_INIT_AUTHENTICATE, the initial quota must be obtained for a single service prepaid solution. If this VSA is not present, the Prime Access Registrar server will not authenticate with the Prepaid billing server.
In Flow 1s, the Prime Access Registrar server sends a call to the billing server to authenticate the prepaid user and possibly determine more information about the subscriber’s account. The Prime Access Registrar server can be configured to generate this packet flow, using a subscriber profile parameter, if the request is from a prepaid subscriber.
Access-Accept (Authentication)
Flow 2b shows the billing server returning the authentication result. The billing server returns a failure if the prepaid subscriber has an inadequate balance.
Flow 2s shows the Prime Access Registrar server sending the Access-Accept to the AAA client. This message flow contains at least one prepaid billing-specific VSA (listed in Table 8-5 ) and might contain other access technology-specific attributes.
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Access-Request (Authorization)
In Flow 3c, the AAA client sends another Access-Request, this time to authorize the subscriber. Table 8-6 lists the attributes required by the Prime Access Registrar server to authorize the subscriber. The session key ID used must be specified using a prepaid VSA pointing to the RADIUS attribute (standard or VSA).
.In Flow 3s, the Prime Access Registrar server sends the Prepaid billing server to obtain a quota. The quota might contain several values depending on the number of measurement parameters chosen.
Access-Accept (Authorization)
Flow 4b shows the billing server returning the quota array for the subscriber.
In Flow 4s, the Prime Access Registrar server converts the quota array received into VSAs and sends an Access-Accept with the assembled VSAs to the AAA client. Table 8-7 lists the prepaid-specific VSAs that might be included in the Access-Accept response message sent to the AAA client. For more detailed information about the VSAs, see Vendor-Specific Attributes.
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Flows 3c through 4s are repeated for every service started or restarted by the AAA client.
However, if the return parameters indicate that the authorization is rejected, an Access-Accept message is generated and sent to the client as shown in Table 8-8 . When this type of error condition occurs, no other VSA is included in the Access-Accept message.
Accounting-Start
In Flow 5c, the AAA client sends the Accounting-Start. In Flow 6s, the Prime Access Registrar server replies with the Accounting-Response.
Data Flow
At this point, the data transfer begins. The AAA client monitors the subscriber’s allocated quotas for metering parameters. A subscriber’s Reauthorization request is generated when a quota for at least one of the metering parameters, is depleted.
Access-Request (Quota Depleted)
Flow 7c shows the client sending an Access-Request to the Prime Access Registrar server because at least one quota has been depleted. The Access-Request includes different measurements of how much of the quotas were used in VSA format. This enables the billing server to account for the usage and manage the subscriber’s balance before assigning a new quota. Table 8-9 lists the attributes returned to the Prime Access Registrar server:
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Accept-Accept (Quota Depleted)
Flow 7s shows the Prime Access Registrar server returning the used quota array to the billing server. The call includes aaa_ebs_reauthoriz(). The billing server sends an updated quota array for the next period to the Prime Access Registrar server.
In Flow 8s, the Prime Access Registrar server converts the quota array into VSAs and sends them to the AAA client.
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Accounting Stop (Session End)
In Flow 9c, the client sends an Accounting-Stop to the Prime Access Registrar server to end the session. The Accounting-Stop message includes an updated quota array with the usage adjustments since the previous authorization in the VSA form.
Table 8-11 lists the attributes included in the Accounting-Stop message set to the Prime Access Registrar server and forwarded to the billing server.
Accounting Response (Final Status)
In Flow 9s, the Prime Access Registrar server sends the used quota array to the billing server in an Accounting-Stop message. Any values returned by the billing server in Flow 10b are discarded.
Flow 10s shows the Prime Access Registrar server sending final Accounting-Response message to the AAA client.
Vendor-Specific Attributes
Vendor-specific attributes are included in specific RADIUS packets to communicate prepaid user balance information from the Prime Access Registrar server to the AAA client, and actual usage, either interim or total, between the NAS and the Prime Access Registrar Server.
Table 8-12 lists the VSAs that will be defined in the API. Table 8-12 also lists the string to be used with Cisco-AVPair below the VSA.
Note VSAs that start with CRB are used for Cisco Radius Billing prepaid service.
Implementing the Prepaid Billing API
A shared library must implement the API functions to perform the various tasks given in the description of each of the function. This needs to be compiled as a shared library and then specified as part of the remote server configuration at the Filename property. See Setting Up a Prepaid Billing RemoteServer or Setting Up a Prepaid Billing RemoteServer.
At startup, Prime Access Registrar loads the library dynamically and registers the API functions, then calls out the library initialization API once at startup. The call to initialize functions initializes various data structures and connections with the billing server, as required.
Note Cisco works with you to develop the prepaid billing service and implement the API. For more information, contact your Cisco systems engineer.
At various times, according to the call flow described in the Prepaid Call Flow Specification (CRB or IS835C), Prime Access Registrar calls out appropriate API functions present in the shared library. The values for the arguments passed to these API calls are purely derived from the incoming RADIUS packet and Prime Access Registrar does not maintain any dynamic information related to the call flow. It is up to the API function to make use of the information passed to it as C structures to contact the Billing server, get appropriate data, and return the same to Prime Access Registrar using the designated arguments.
Note See the API specifications for more details pertaining to the arguments and return values of the API.
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