All MIBs › CISCO-CEF-MIB › cefLMPrefixSpinLock
cefLMPrefixSpinLock
Module: CISCO-CEF-MIB
OID (symbolic): CISCO-CEF-MIB::cefLMPrefixSpinLock
OID (numeric): 1.3.6.1.4.1.9.9.492.1.1.3
Node type: OBJECT-TYPE
Type: TestAndIncr
Access: read-write
Description: An advisory lock used to allow cooperating SNMP Command Generator applications to coordinate their use of the Set operation in creating Longest Match Prefix Entries in cefLMPrefixTable.
When creating a new longest prefix match entry, the value of cefLMPrefixSpinLock should be retrieved. The destination address should be determined to be unique by the SNMP Command Generator application by consulting the cefLMPrefixTable. Finally, the longest prefix entry may be created (Set), including the advisory lock.
If another SNMP Command Generator application has altered the longest prefix entry in the meantime, then the spin lock's value will have changed, and so this creation will fail because it will specify the wrong value for the spin lock.
Since this is an advisory lock, the use of this lock is not enforced, but not using this lock may lead to conflict with the another SNMP command responder application which may also be acting on the cefLMPrefixTable.
What is cefLMPrefixSpinLock?
This is an advisory spin-lock object that cooperating SNMP management applications read and increment-on-write to coordinate creating new longest-match prefix search entries without colliding with each other. Because multiple management stations could otherwise try to create a lookup entry with the same index simultaneously, this lock is the specific mechanism that lets one manager claim the right to create the next entry, preventing race conditions in what is otherwise a shared, mutable table. A management application would read this object's current value, then include that same value in its Set request creating a new cefLMPrefixTable row; if another manager's Set had already incremented the lock in between, the create request would fail, telling the first manager to retry with the new value.
Examples
Walk all instances (SNMPv2c):
snmpwalk -v2c -c public <target> 1.3.6.1.4.1.9.9.492.1.1.3 snmpwalk -v2c -c public <target> CISCO-CEF-MIB::cefLMPrefixSpinLock
Get a specific instance (index 1):
snmpget -v2c -c public <target> 1.3.6.1.4.1.9.9.492.1.1.3.1 snmpget -v2c -c public <target> CISCO-CEF-MIB::cefLMPrefixSpinLock.1
Set instance 1 (SNMPv2c):
snmpset -v2c -c private <target> 1.3.6.1.4.1.9.9.492.1.1.3.1 s <value>
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OID Breakdown
Upper-level ancestors (8 from the standard OID tree / other modules)
| Numeric OID | Name | Module |
|---|---|---|
| 1 | iso | LANART-AGENT |
| 1.3 | org | AirPair-MIB |
| 1.3.6 | dod | AirPair-MIB |
| 1.3.6.1 | internet | AirPair-MIB |
| 1.3.6.1.4 | private | AirPair-MIB |
| 1.3.6.1.4.1 | enterprises | AirPair-MIB |
| 1.3.6.1.4.1.9 | cisco | CAT2600-MIB |
| 1.3.6.1.4.1.9.9 | ciscoMgmt | CISCO-SMI |
| Numeric OID | Name | Module |
|---|---|---|
| 1.3.6.1.4.1.9.9.492 | ciscoCefMIB | CISCO-CEF-MIB |
| 1.3.6.1.4.1.9.9.492.1 | ciscoCefMIBObjects | CISCO-CEF-MIB |
| 1.3.6.1.4.1.9.9.492.1.1 | cefFIB | CISCO-CEF-MIB |
| 1.3.6.1.4.1.9.9.492.1.1.3 | cefLMPrefixSpinLock | CISCO-CEF-MIB |