- Top Results
Answer
This article explains briefly the basics of SNMP. Declares the basic terms of the protocol. It also explains what part of the protocol is supported by Bosch cameras.
Basics of SNMP and terms.
Simple Network Management Protocol (SNMP) is a common protocol to monitor the health status of a system. Such a monitoring system typically has a central management server that collect all the data from the system’s compatible components and devices. SNMP provides two methods to gain the system health status:
- The network management server can poll the health status of a device via SNMP requests.
- Devices can actively notify the network management server about their system health status in case of error or alarm conditions through sending SNMP traps to the SNMP server. Such traps must be configured inside the device.
Basic terms:
- MIB Management Information Base, is an ASCII text file that describes SNMP network elements. It is the dictionary of the SNMP language — every object referred to in an SNMP message must be listed in the MIB. Each element in the MIB is given an object identifier, or OID.
- An OID is a number that uniquely identifies an element in the SNMP universe. Each OID is associated with a human-readable text label. When your SNMP device sends a Trap or a GetResponse, it transmits a series of OIDs, paired with their current values.
Example (from bvip_snmp.mib) – OID -- 1.3.6.1.4.1.3967.1.5.1.1 mac-address
- SNMP manager collects and organizes SNMP information from managed devices (agents). It uses the MIB as a codebook for translating the OID numbers into a human-readable display.
- PDU (Protocol Data Units): In the second section of this article, there are examples of PDU types Trap and GetRequest. For more information on the existing PDUs (that are different in different SNMP versions), please refer to SNMP documentation.
SNMP also allows configuration of some variables inside devices and components. The information, which messages a device supports and which traps it can send, is derived from the Management Information Base, the so-called MIB file, a file that is delivered with a product for easy integration into a network monitoring system. There are three different version of the SNMP protocol:
–SNMP version 1
SNMP version 1 (SNMPv1) is the initial implementation of the SNMP protocol. It is widely used and has become the de facto standard protocol for network management and monitoring. But SNMPv1 has become under threat due to its lack of security features. It only uses ‘community strings’ as a kind of passwords, which are transmitted in clear text.Thus, SNMPv1 shall only be used when it can be assured that the network is physically protected against unauthorized access.
–SNMP version 2
SNMP version 2 (SNMPv2) included improvements in security and confidentiality, amongst others, and introduced a bulk request to retrieve large amounts of data in a single request. However, its security approach was considered way too complex,hindering its acceptance. Thus, it was soon pushed out by version SNMPv2c, which equals SNMPv2 but without its controversial security model, reverting to the community-based method from SNMPv1instead, similarly lacking security.
–SNMP version 3
SNMP version 3 (SNMPv3) mainly adds security and remote configuration enhancements. These include improvements on confidentiality by encryption of packets, message integrity and authentication. It also addresses large-scale deployment of SNMP.
-MIB and MIB II
A management information base (MIB) is a formal description of a set of network objects that can be managed using the Simple Network Management Protocol (SNMP). MIB-I refers to the initial MIB definition and MIB-II refers to the current definition.
-Standard MIB
Standard MIB objects are designed for a wide variety of technologies and network devices. These MIB objects cover a large range of performance monitoring parameters that are valid for any network device in general.
-Private MIB
Private MIB extentions are created in order to cover vendor-specific performance monitoring parameters.
Bosch cameras SNMP and MIB
To check what SNMP version does a particular camera support, check the data sheet of the device. (Find it under your device in the product catalogue - https://www.boschsecurity.com/xc/en/product-catalog/)
- since FW 6.40 onwards Bosch devices support:
- SNMP v1 legacy with MIB II (The term legacy is used in some documents to note that this is SNMP v1 and there is Bosch private MIB II extention )
- and SNMP v3 basic integration. This means that there is no Bosch private MIB file and only the standard system MIB file can be used. There is no trap support for SNMP v3 implementation.
- up to FW 6.40 Bosch devices support SNMP v1 with Bosch MIB II extention.
Recent platforms CPP13 and CPP14 provide a full private MIB integration for both SNMP v1 and v3, including trap support.
Structure of the MIB (bvip_snmp.mib)
- The file starts with description in form of comments (comment starts with --)
- List of the traps
- All Commands – Object Types, data you can read and sometimes write. To read and write the SNMP manager sends to the agent commands (ex. GetRequest and SetRequest) encapsulated in PDUs.
- The body of the MIB file is a tree of all MIB Object - all characteristics of the device that are controlable via SNMP
Fig. Object Type structure
- Access - the most important entry in an object-type description. This controls whether you can read and write the data described in the object-type. There are three access settings:
- read-only - request the data in with GetRequest, GetNext, Walk, etc
- read-write- retrieve the data in a GetRequest and write new data for the object-type in a SetRequest.
- not-accessible - you can’t request the data or write new data
Details how to configure Bosch camera to send SNMP traps:
