eSNMP API Routines esnmp_register
A subtree is identified by the base MIB name and the corresponding OID number of the node that is the parent of all MIB variables contained in the subtree. For example: The MIB II tcp subtree has an OID of 1.3.6.1.2.1.6. All elements subordinate to this have the same first seven digits and are included in the subtree’s object table. The subtree can also be a single MIB object (a leaf node) or even a specific instance.
By registering a subtree, the subagent indicates that it will process eSNMP requests for all MIB variables (or OIDs) within that subtree’s range. Therefore, a subagent should register the most fully qualified (longest) subtree that still contains its instrumented MIB variables.
The master agent does not permit a subagent to register the same subtree more than once. However, subagents can register subtrees with ranges that overlap the OID ranges of subtrees previously registered, and subagents can also register subtrees registered by other subagents.
For example, TCP/IP Services supports MIB II. In the eSNMP environment, the os_mibs subagent registers the MIB II subtree ip (OID 1.3.6.1.2.1.4).
TCP/IP Services also provides the gated subagent, which registers the ipRouteEntry MIB subtree (OID 1.3.6.1.2.1.4.21.1).
These MIBs are registered at priority 1. Any subagent that registers at a higher priority (greater than 1) overrides these registrations.
A request for IpRouteIfIndex (OID 1.3.5.1.2.1.4.21.1.2) is passed to the gated subagent. Requests for other ip variables, such as ipNetToMediaIfIndex (OID 1.3.5.1.2.1.4.22.1.1) are passed to the os_mibs subagent. If the gated subagent terminates or unregisters the ipRouteEntry subtree, subsequent requests for ipRouteIfIndex will go to the os_mibs subagent. This occurs because the ip subtree, which includes all ipRouteEntry variables, is now the authoritative region of requests for ipRouteIfIndex.
Return Values
SNMP_LIB_OK | The esnmp_register routine has completed |
| successfully. |
ESNMP_LIB_BAD_REG | The esnmp_init routine has not been called, the |
| timeout parameter is invalid, or the subtree has |
| already been queued for registration. |
ESNMP_LIB_LOST_ | The subagent has lost communications with the |
CONNECTION | master agent. |
Note that the return value indicates only the initiation of the request. The actual status returned in the master agent’s response will be returned in a subsequent call to the esnmp_poll routine in the state field.
Example
#include <esnmp.h> |
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#define RESPONSE_TIMEOUT | 0 | /* use the default time set |
|
| in OPEN message */ |
#define REGISTRATION_PRIORITY 10 | /* priority at which subtrees | |
|
| will register */ |
int status;
extern SUBTREE ipRouteEntry_subtree;
