By enabling IP accounting, users can see the number of bytes and packets switched through the Cisco IOS? software on a source and destination IP address basis. Only transit IP traffic is measured and only on an outbound basis; traffic generated by the software or terminating in the software is not included in the accounting statistics.
To maintain accurate accounting totals, the software maintains two accounting databases: an active and a checkpointed database. There are two tables in OLD-CISCO-IP-MIB.my, which are lipCkAccountingTable and lipAccountingTable (the active database). The actCheckPoint copies the active database into the checkpoint database. Consequently, the show ip accounting command is cleared.
A network management system (NMS) can use checkpoint MIB variables to analyze stable data in the checkpoint database. The running, or active, database is copied into the checkpoint database. If the checkpoint database already has data obtained previously from the active database, the router appends the latest copy of the active database to the existing data in the checkpoint database. The checkpoint database stores data retrieved from the active database until actCheckPoint is set, or until you delete the contents of this database by using the clear ip accounting [checkpoint] command.