Initialisation
References
- Definition
- SOS is assigned the OID: 1.3.6.1.4.1.24723
- explanation: iso(1) identified-organization(3) dod(6) internet(1) private(4) enterprise(1) 24723
- see http://oid-info.com/get/1.3.6.1.4.1.24723
Resources
- Articles
- Network Management and SMTP
- Microsoft Technet Article: How SNMP works
- Downloads
Prerequisites
- Each message transferred by SNMP has to be assigned a respective OID that is an extension to the SOS assigned OID
- OIDs used for a product such as JobScheduler, YADE would be assigned a product extension.
- For a specific product the OID is further extended for use by messages for that product.
- OIDs of all SOS products are collected into one MIB.
Component Architecture
- Presentation: JobScheduler_SNMP_Support.pptx
- Document: JobScheduler_SNMP_Support.pdf
Implementation
Prerequisites
- Implementation for SNMPv3
- No previous versions are supported
SNMP Messages
SNMP Message Types
- Communication makes use of a set of predefined message types.
- Excerpt extracted from chapter SNMP Message Types in http://technet.microsoft.com/en-us/library/cc783142(v=ws.10).aspx#w2k3tr_snmp_how_oqdv:
| SNMP Message | From / To | Message Description |
|---|---|---|
Get | Manager / Agent | Accesses and retrieves the current value of one or more MIB objects on an SNMP agent. |
GetResponse | Agent / Manager | Replies to a Get, GetNext, or Set operation. |
GetNext | Manager / Agent | Browses the entire tree of MIB objects, reading the values of variables in the MIB sequentially. Typically, you use GetNext to obtain information from selected columns from one or more rows of a table. GetNext is especially useful for browsing dynamic tables, such as an internal IP route table or an ARP table, reading through the table one row at a time. |
GetBulk
| Manager / Agent | Retrieves data in units as large as possible within the given constraints on the message size. GetBulk, which accesses multiple values at one time without using a GetNext message, minimizes the number of protocol exchanges required to retrieve a large amount of information. |
Set | Manager / Agent | Changes the current value of a MIB object. In order to update a MIB value on the SNMP agent, the SNMP manager must have write access to the object. Set is used infrequently, because most MIB objects are read-only by default, so that unauthorized changes cannot be made. |
Trap | Agent / Manager | Notifies the specified SNMP manager (the trap destination) when an unexpected event occurs locally on the managed host. You can use traps for limited security checking (such as notifying the trap destination if the agent receives an information request from an SNMP manager that it does not recognize) or for troubleshooting (such as notifying the trap destination if the WINS service fails). |
- Addiitional message types are used for acknowledgement:
| SNMP Message | From / To | Message Description |
|---|---|---|
Inform | Manager / Agent | This command is similar to the Trap initiated by the Agent, additionally Inform includes confirmation from the SNMP Manager on receiving the message |
| Response | Agent / Manager | It is the command used to carry back the value(s) or signal of actions directed by the SNMP Manager |
SNMP Trap Types
- Communication makes use of a set of predefined trap types.
- Excerpt extracted from chapter SNMP Trap Types in http://technet.microsoft.com/en-us/library/cc783142(v=ws.10).aspx#w2k3tr_snmp_how_oqdv:
| Trap Type | Trap Name | Description |
|---|---|---|
0 | ColdStart | The SNMP agent initialized its configuration tables. |
1 | WarmStart | The SNMP agent re-initialized its configuration tables. |
2 | LinkDown | The state of a network adapter on the SNMP agent changed from up to down. |
3 | Linkup | The state of a network adapter on the SNMP agent changed from down to up. |
4 | authenticationFailure | The SNMP agent received a message from an SNMP manager, but the message contained an invalid community name. |
5 | egpNeighborLoss | The SNMP agent could not communicate with its Exterior Gateway Protocol (EGP) peer. |
6 | enterpriseSpecific | Reserved for vendor-defined error conditions and error codes. |
Communication
- UDP is the only protocol being used.
- By default SNMP uses port 161 for request / response.
- Commands for Trap and Inform use port 162 for communication.
Implementation Architecture
- JobScheduler Monitoring Interface
- is moved from operation as a job to operation in a servlet container
- works independently from JobScheduler
- uses the JobScheduler database as exclusive source of information
- JobScheduler SNMP Agent
- is implemented as a concurrent process in the JobScheduler Monitoring Interface