The Call Accounting Manager (CAM) generates Call Detail Records (CDRs) and supports accounting events logging to the SBC Core. The SBC provides the ability to map CDR fields and other input parameters to Remote Authentication Dial In User Service (RADIUS) attributes (standard as well as vendor-specific attributes) and send to the appropriate RADIUS server.
SBC Core supports to configure one remote server per SBC for the purpose of authenticating users from this server using RADIUS protocol. The username and encrypted password are sent to the remote RADIUS server in an ACCESS_REQUEST packet. The user is allowed/denied access to the SBC based on the response from the RADIUS server.
SBC users are currently segregated into the following groups which define the privileges of each user. Access to data/commands is allowed/prevented based on the group of the user who is trying to acquire the access.
Since the RADIUS protocol does not provide a means to assign users to a group, the implementation currently hard codes every RADIUS authenticated user to the Administrator group.
For detailed information on RADIUS authentication, refer to Configuring SBC for RADIUS Authentication.
Viewing Billing Records
As calls traverse the SBC, Call Detail Records (CDRs) are generated and stored in
/var/log/sonus/evlog/evlog directory. You can view these CDR by looking at files with the “.ACT” extension. It is useful to view these ACT logs during call debugging (to get the originating trunk group, calling and called numbers, codec used, etc.).
You may also view billing records (and other logs) from the EMA Platform Mode. Refer to Administration - Accounting and Logs for more information.
When downloading billing records (or other logs), you must use port 2024 to SFTP files off of the SBC.
Call Detail Record Format
This section describes the ASCII and streaming Call Detail Record (CDR) format.
SBC may insert non-ASCII characters in CDRs when messages are parsed in the initial INVITE.
Various Sonus elements such as GSX 9000, PSX, and SBC use many of the same CDR fields. Because of this, some fields in the “Accounting Records” table below do not apply to SBC call details, but instead simply indicate pass-though type messages (for example, ISUP and PSTN fields).
For more information on known limitations, refer to the applicable release notes at SBC Release Information page.
Accounting File Version
The CAM version of SBC release V06.00.00 is 85.00.00 (major CAM version is 85, minor CAM version is 0, special CAM version is 0). The associated hex format of the CAM file version is "00550000" as shown in below header example.
Sonus Networks, Inc.00000000FF600000550000000000000060V06.00.00 00000000000000000000000000000000000ACT2014112715113200000000000000.
Every event log file, including accounting logs, contains a file header. This header consists of a 128-character string terminated by a carriage return. Each field in the event log file header is defined in the following table:
ASCII OEM string, blank padded, (for example "Sonus Networks, Inc.")
Old CAM File Version. Always "FF".
Hex offset to the Event Log Type, or the number of bytes from the beginning of the record to the beginning of the Event Log Type field (in the above example, "60").
New CAM File Version. This value is 00550000, and consists of:
Hex offset to start of data. In this example, "0060".
SBC software revision. In this example, "V06.00.00".
Event Log Type (same as file extension). In this example, "ACT".
File creation time.
Header terminator (carriage return)
The one line footer, below, is appended to each log file (including accounting logs) when the file is closed under controlled conditions.
DDMMYYYY HHMMSS: File administratively closed.
Controlled conditions include CLI commands (for example,
set oam eventLog
acct rolloverAction...) and automatic roll-overs when maximum file size is reached.
When an uncontrolled file closure occurs, such as an SBC switch-over or system failure, this footer may not be present.
How to Set Up SFTP from SBC to a CDR Server
If the CDR server is configured, SBC transfers the files through SFTP to the configured destination.
To create the CDR server, use the following command syntax:
An example to show the CDR server configuration and check the configuration is as follows:
Initially, the accounting field is not set to ftp or automatically roll over. Use the following command to view Rollover setting for accounting (See "acct" row in the example):
To create the accounting file rollover and ftp, use the following command syntax:
An example of the configuration and display of the accounting file rollover and ftp is as follows:
View CDR Server status using the following command:
Verify that the files were transferred to the FTP server by logging in to the CDR server and executing the following command:
Execute the following command to view the successful and failed CDR file transfer:
SBC Standard Attributes
The SBC RADIUS application uses standard attributes from the RADIUS when possible. For CDR fields that cannot be mapped to the standard attributes, vendor-specific attributes are defined. The SBC allows instances of the standard attributes in Accounting request message as per following table:
The IP Address of the SBC generating accounting request.
The configured NAS Identifier for a given SBC. When sending RADIUS accounting messages, the NAS-Identifier field is populated with the corresponding value configured for the RADIUS server to which message is sent.
The type of accounting message sent by the SBC. The SBC uses the appropriate value of Acct-Status-Type corresponding to the CDR type to be generated.
Uniquely identifies accounting records for a given call. It is possible to match all accounting records for a given call when correlating call records.
The number of seconds during which the user received service (duration of the call).
The class of termination cause. This value is derived from the disconnect reasons class value.
SBC accounting records may be sent to three different locations:
- Local hard disk—If accounting is enabled, then ASCII records are always written to the local disk.
- An external server:
- To DSI-L0 server—If configured, the ASCII records are transferred to the external Sonus DSI server through SFTP.
- To external billing server from IMS network via Rf Interface.
- RADIUS server—RADIUS accounting records can be generated and sent to an external RADIUS server.
Accounting File Roll-Over
The SBC application maintains a configurable maximum of up to 1024 accounting files. Once the configured limit of files is reached, the application deletes the oldest files first to accommodate the new files.
When accounting file names reach the maximum value of 1FFFFFF.ACT, the next file name rolls over to 1000001.ACT. Use the “Rename Open Files” flag to rename the most recent accounting file with the ”ACT.OPEN” extension. This flag is accessible from the EMA at “System Configuration” > “CDR and Servers” tab.
Global Charge Reference
The Global Charge Reference (GCR) feature allows correlation of calls across networks where the calls are originated from and terminated at different third-party devices. The GCR field is populated in the CDRs of the SBC if the GCR is received in a gateway protocol message from a GSX9000.
The GSX9000 receives or generates the GCR parameter through an ISUP parameter. The GCR is used in conjunction with SIP call-id’s to associate calls that interwork between SIP and ISUP protocols across multiple network devices.
RADIUS is a standardized protocol for supporting Authentication, Authorization, and Accounting (AAA) management in a distributed client-server architecture. The SBC acting as a RADIUS client can send call-accounting records to an external RADIUS server. For a description of Sonus CDR to RADIUS VSA field mapping, refer to Managing Billing Records.
The following message types are supported by RADIUS protocol:
- Accounting Request
- Accounting Response
The accounting request and its response for a transaction methodology is described below.
- The SBC sends an accounting-request with Accounting-Status-Type value "Accounting-on". At a later time, this transaction informs the server about the new accounting client that will send the accounting messages to the NAS/resource usage by user.
- When the SBC connects the call, the accounting starts. The accounting-request contains the Accounting-Status-Type with the value "Start". The "Start" records contains the following:
- User identification
- Network address
- Point of attachment
- Unique session identifier
- Next, the SBC records the status change by NAS to the RADIUS server for this active session. The accounting-request now contains the Accounting-Status-Type with the value "Interim". The interim record usually conveys the current session duration and information on the current data usage.
- When the user network access is closed, the NAS issues a final Accounting Stop record to the RADIUS server, providing the information on the final usage in the terms of the following:
- Packets transferred
- Data transferred
- Reason for disconnect
- Other information related to the call
The accounting-request contains the Accounting-Status-Type with the value "Stop". The primary purpose of this data is to bill the user. The data is also used for statistical purposes and for general network monitoring.
Renaming Open Accounting Files
The SBC includes the ability to rename a currently-open accounting file using a known suffix to make it easily identifiable by external applications. To activate this feature, simply enable the flag “Rename Open Files” using EMA GUI or CLI.
CLI syntax example:
Once this flag is enabled, on the next accounting file open activity, the suffix .OPEN is appended to the filename using the format <shelf><sequence number>.ACT.OPEN (currently open files are not affected).
For example, as accounting file 1000099 is created with this feature already enabled, the file is named “1000099.ACT.OPEN”.
For configuration details, refer to:
Rf Interface Support
The SBC Core acting as a P-CSCF or IBCF supports Rf interface-based offline billing in compliance with standard IMS as well as file-based and stream-based CDRs. The SBC can select either CDR/streaming-based charging or Rf Interface depending on whether the system-wide flag, enableRfApp, is enabled or not. Refer to Signaling - Global - CLI or Signaling - Diam Sig Controls for configuration details.
The SBC Diameter node supports both Rf application along with the existing Rx application. The Diameter node uses "Route Table" to find peer for outbound request based on destination realm and application.
CDR Server Remote Port Configuration
The SBC supports transferring the call accounting files (.
ACT) to the CDR server through a user configured port. The SBC also supports using the Secure Shell (SSH) public keys instead of password to authenticate with the remote CDR server.
The following parameters are added in CDR server configuration to set remote port and ssh key based authentication:
User can either use the existing username/password or the SSH public key to authenticate with the remote CDR server. The parameter
useSshKeyFile must be enabled to generate the SSH public key.
To generate a new SSH public key, execute the following command:
The generated SSH public key must be installed on CDR server to use ssh key based authentication from SBC. The SSH public key must be copied to the remote CDR server file
/home/<user>/.ssh/authorized_keys. If the private key is compromised, the key must be re-generated. Once the key is re-generated, the CDR server must be updated with the new key.
- The SSH public key generated for the primary CDR server can also be used to authenticate the secondary CDR server. The SSH public key can be installed on both primary and secondary CDR servers.
The configured user must have access to
/home/<user>/.sshfor reading the public key.
Configuring CDR Server Remote Port
Using SSH Public Key for CDR Server Authentication
Use the SSH public key for CDR server authentication to accomplish the following actions:
- Enabling SSH Key Based Authentication
- Generating the SSH Public Key
- Copying and Installing the SSH Public Key to CDR Servers
Enabling SSH Key Based Authentication
To enable SSH key based authentication, execute the following command:
Generating the SSH Public Key
To generate a new SSH public key, execute the following command:
Copying and Installing the SSH Public Key to CDR Servers
The SSH public key is copied to the remote CDR server file
For configuration details, refer to Accounting - CLI.