Introduction
1.6 USER FUNCTIONS
The SNMP primitives may be used to accomplish the following functions:
•Obtain the ELS10-26’s current value of certain parameters - the NMS uses the GetRequest or GetNextRequest PDU, and the ELS10-26 responds with a GetResponse PDU. If the NMS issues
a GetRequest for an unsupported parameter, the ELS10-26 sends a GetResponse with a noSuchName ErrorStatus1. If the NMS issues a GetNextRequest for an unsupported parameter, the ELS10-26 skips to the next object.
•Change the ELS10-26’s value of certain parameters - the NMS uses the SetRequest PDU, and the ELS10-26 responds with a GetResponse PDU. The ELS10-26 will change both its current value and its local default to be used when the ELS10-26 reboots, unless noted otherwise.
•Obtain the current value of certain parameters and simultaneously change the value of other parameters - the NMS uses the SetRequest PDU, and the ELS10-26 responds with a GetResponse PDU. For the parameters which are being obtained rather than changed, the NMS must use the ASN.1 NULL value with the SetRequest PDU.
•Provide notification of significant events - the ELS10-26 uses the Trap PDU and/or the GetResponse PDU. The NMS uses the SetRequest PDU to control the frequency that the ELS10-26 may send Trap PDUs.
1.If implementing the parameter is required, it might seem more reasonable to return a GetResponse with no error and the ASN.1 NULL value as the parameter’s value; however, leading authorities such as Marshall T. Rose (author of The Simple Book) suggest that noSuchName be returned, because many existing SNMP management stations do not handle NULL values correctly.
