| Description | A registration table for element types managed by this
system.
The Element Type Registration table allows the manager to
learn what element types are being managed by the system and
to register new types, if necessary. An element type is
registered by providing the OID of an SNMP object (i.e.,
without the instance). Each SNMP instance that exists under
that object is a distinct element. The index of the element is
the index part of the discovered OID. This index will be
supplied to policy conditions and actions so that this code
can inspect and configure the element.
For example, this table might contain the following entries.
The first three are agent-installed, and the 4th was
downloaded by a management station:
OIDPrefix MaxLatency Description StorageType
ifEntry 100 mS interfaces - builtin readOnly
0.0 100 mS system element - builtin readOnly
frCircuitEntry 100 mS FR Circuits - builtin readOnly
hrSWRunEntry 60 sec Running Processes volatile
Note that agents may automatically configure elements in this
table for frequently used element types (interfaces, circuits,
etc.). In particular, it may configure elements for whom
discovery is optimized in one or both of the following ways:
1. The agent may discover elements by scanning internal data
structures as opposed to issuing local SNMP requests. It is
possible to recreate the exact semantics described in this
table even if local SNMP requests are not issued.
2. The agent may receive asynchronous notification of new
elements (for example, 'card inserted') and use that
information to instantly create elements rather than
through polling. A similar feature might be available for
the deletion of elements.
Note that the disposition of agent-installed entries is
described by the pmPolicyStorageType object. |