METHOD OF DOING AN SNMP CANCEL OF A PRINT JOB
Original Publication Date: 1999-Dec-01
Included in the Prior Art Database: 2003-Jun-18
Disclosed is a method for an application to use the SNMP (Simple Network Management Protocol) protocol to cancel print jobs in a secure way. Canceling a print job is normally done using the operator panel of the printer. However, being able to cancel a print job using SNMP would be very useful to the user, as jobs could be canceled remotely, from a workstation, at any time after the job has started to be submitted. For example, a job could be canceled after the job has been fully sent to the printer, which is not possible without either having a cancellation mechanism that is separate from the job submission stream, or having a job submission stream that monopolizes the printer’s attachment until job completion. To cancel using SNMP, the printer must support an entry is some MIB (Management Information Base) for every job submitted. The method used is to define a write-only oid associated with each job. When a value is written to that oid, this is used as a signal to the SNMP agent on the printer that the job should be canceled. In this way, an “out of band” (that is, not part of job submission) cancel can be done on a print job. This can, of course, lead to problems with "malevolent" users canceling jobs by simply writing to that oid. The solution to this is to only do the cancel if the oid is set to a specific value. However, since the network can be sniffed, a fixed specific value can easily be found out and used by such users.