SNMPV1PDUVarBindList-alistofVariableIDandVariable Value:VariableIDVariableValueVariableIDObiectldentifierofthevariable defined in SMl specificationVariableValueactual value,whichcouldbe integer,iP address,etcCOMP4690,byDrXiaowen Chu,HKBU
COMP4690, by Dr Xiaowen Chu, HKBU SNMPv1 PDU ⚫ VarBindList ⎯ a list of Variable ID and Variable Value: ⚫ Variable ID ⎯ Object Identifier of the variable defined in SMI specification ⚫ Variable Value ⎯ actual value, which could be integer, IP address, etc. Variable ID Variable Value
SNMP CommandsSNMPv1 commands (numbered 0 thru 4)Get-Requestrequest value(s)from agent MIBGet-Next-Reguestrequestnext MiB element(basedon objectidentifier)inlexicographic orderCan use this to“walk"the MB treeGet-ResponseresponsefromagentSet-Requestwrite a value in agent's MIBTrap -unsolicited message from agent, to inform themanaging entity of exceptional eventsSNMPv2 has two more commands:Get-Bulk-Requestget values in largeblock of dataInform-Requestusedbyamanaging entityto notifyanother managing entity of MiB informationCOMP4690,byDrXiaowenChu,HKBU
COMP4690, by Dr Xiaowen Chu, HKBU SNMP Commands ⚫ SNMPv1 commands (numbered 0 thru 4) ⚫ Get-Request ⎯ request value(s) from agent MIB ⚫ Get-Next-Request ⎯ request next MIB element (based on object identifier) in lexicographic order ⚫ Can use this to “walk” the MIB tree ⚫ Get-Response ⎯ response from agent ⚫ Set-Request ⎯ write a value in agent’s MIB ⚫ Trap ⎯ unsolicited message from agent, to inform the managing entity of exceptional events ⚫ SNMPv2 has two more commands: ⚫ Get-Bulk-Request ⎯ get values in large block of data ⚫ Inform-Request ⎯ used by a managing entity to notify another managing entity of MIB information
SNMP TrapTrap PDU is of the formAgentGenericSpecificTimeVarBindListEnterpriseTrapTrapStampAddressNumberNumberEnterprise Obiect ldentifier for device thatcreated trap messageAgent address IP address of device Generic trap number 7 categories Specific trap number code numberTime stamp - time since device initializedVarBindListsame as defined previouslyCOMP4690,byDrXiaowen Chu,HKBU
COMP4690, by Dr Xiaowen Chu, HKBU SNMP Trap ⚫ Trap PDU is of the form ⚫ Enterprise ⎯ Object Identifier for device that created trap message ⚫ Agent address ⎯ IP address of device ⚫ Generic trap number ⎯ 7 categories ⚫ Specific trap number ⎯ code number ⚫ Time stamp ⎯ time since device initialized ⚫ VarBindList ⎯ same as defined previously Enterprise Agent Generic Specific Time VarBindList Address Trap Trap Stamp Number Number