/mcpmark. The post-processing applications can later retrieve the buffered historical data to re-get any lost, corrupted, or missing data. The CDRM feature, which is not aware of the flat file format, does not manipulate the file contents. The CDRM feature handles CDR files and CMR files in the same manner. Note CDRM comprises two default services, the CDR Agent and the CDR Repository Manager, and one activate service, CDR onDemand Service. CDR Agent As part of the CDRM feature, a resident component on the server or node within a Unified Communications Manager installation acts as the CDR Agent. On the server or nodes were both Unified Communications Manager and the CDR Agent are running, Unified Communications Manager writes the CDRs into CDR flat files in comma separated value (CSV) format. A special control character (“_”) that is prefixed to the filename by the call processing module that indicates that the file is not available for transfer. If this control character is not present, the system assumes that the file is available for transfer, and the CDR Agent then SFTPs those files to the designated CDR repository node. Upon a successful transfer, the system deletes the local copy of the file. Reliability gets the highest priority for the CDRM feature. CDRs comprise important financial data, so the goal of this feature is to guarantee that no CDR is lost. The Unified Communications Manager continuously writes CDRs to flat files, closes existing flat files, and opens new ones. The number of records that are written varies by the type of call and the significant changes that occur during a call: such as, ending the call, transferring the call, redirecting the call, splitting the call, or joining the call. On Linux platforms, the CDR Agent collects the CDR/CMR flat files that the Unified Communications Manager generates and sends these files to the publisher through SFTP. The Windows versions of do not support SFTP. On Windows platforms, the CDR Agent copies the files directly from the subscriber disk to the shared publisher disk. Note CDR Repository Manager Within a Unified Communications Manager server or cluster, one instance of the CDR Repository Manager runs on the CDR Repository server or node. It manages CDR files that are received from the Unified Communications Manager nodes and periodically sends the files to the specified customer/third-party billing servers via FTP/SFTP. When the file arrives on the CDR Repository server or node, the CDR Repository Manager detects it. The system archives the file in a directory that is dedicated to the date that is indicated by the UTC timestamp that was placed in the filename when the file was created. If any external billing server is specified in the CDRM configuration, the system creates an empty file in each of the corresponding folders for CAR and the billing servers, if CAR or the corresponding billing server is activated. The CDR Agent monitors new CDR/CMR files that are generated on CallManager servers or nodes by the call processing component. It sends the files to the CDR Repository node and then deletes the local copy after the file is pushed out. The file sender component of the CDR Repository Manager detects these Call Reporting and Billing Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs 204 CDR Records CDR Agent