- Cabletron IP Router Reference Guide

Introduction
1-7
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
ErrorStatus
1
. 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.