Chapter 6:SNMP Management:SNMPv2 6.2 SNNPv2 System Architecture The SNMPv2 system architecture looks essentially the same as that of version 1,shown in Figure 4.9. However,there are two significant enhancements in the SNMPv2 architecture.First,there are seven messages instead of five (compare Figure 4.9). Second,two manager applications can communicate with each other at peer level.Another message, report message,is missing from Figure 6.2 because, even though it has been defined as a message,the SNMPv2 Working Group did not specify its details. It is left for the implementers to generate the specifications.It is not currently being used
Chapter 6: SNMP Management: SNMPv2 6.2 SNNPv2 System Architecture The SNMPv2 system architecture looks essentially the same as that of version 1, shown in Figure 4.9. However, there are two significant enhancements in the SNMPv2 architecture. First, there are seven messages instead of five (compare Figure 4.9). Second, two manager applications can communicate with each other at peer level. Another message, report message, is missing from Figure 6.2 because, even though it has been defined as a message, the SNMPv2 Working Group did not specify its details. It is left for the implementers to generate the specifications. It is not currently being used
The messages get-request,get-next request,and set-request are the same as in version 1 and are generated by the manager application.The message response is also the same as get-response in version 1, and is now generated by both the agent and the manager applications.It is generated by the agent application in response to a get or set message from the manager application.It is also generated by the manager application in response to an inform-request message from another manager application. An inform-request message is generated by a manager application and transmitted to another manager application.The receiving manager application responds with a response message.This set of communication messages is a powerful enhancement in SNMPv2,because it makes two network management systems interoperable
The messages get-request, get-next request, and set-request are the same as in version 1 and are generated by the manager application. The message response is also the same as get-response in version 1, and is now generated by both the agent and the manager applications. It is generated by the agent application in response to a get or set message from the manager application. It is also generated by the manager application in response to an inform-request message from another manager application. An inform-request message is generated by a manager application and transmitted to another manager application. The receiving manager application responds with a response message. This set of communication messages is a powerful enhancement in SNMPv2, because it makes two network management systems interoperable
Chapter 6:SNMP Management:SNMPv2 The message get-bulk-request is generated by manager application.It is used to transfer large amounts of data from the agent to the manager, especially if it includes retrieval of table data.The retrieval is fast and efficient.The receiving entity generates and fills data for each entry in the request and transmits all the data as a response message to the originator of the request. An SNMPv2-trap event,known as trap in version 1,is generated and transmitted by an agent process when an exceptional situation occurs.The destination to which it is sent is implementation-dependent.The PDU structure has been modified to be consistent with other PDUs
Chapter 6: SNMP Management: SNMPv2 The message get-bulk-request is generated by a manager application. It is used to transfer large amounts of data from the agent to the manager, especially if it includes retrieval of table data. The retrieval is fast and efficient. The receiving entity generates and fills data for each entry in the request and transmits all the data as a response message to the originator of the request. An SNMPv2-trap event, known as trap in version 1, is generated and transmitted by an agent process when an exceptional situation occurs. The destination to which it is sent is implementation-dependent. The PDU structure has been modified to be consistent with other PDUs
6.3 SNMPv2 Structure of Management Information There are several changes to SMI in version 2,as well as enhancements to SMIv2 over that of SMIv1. The SMIv2 [RFC 1902]is divided into three parts: module definitions,object definitions, and notification definitions. The module definitions describe the semantics of an information module and are formally defined by an ASN.1 macro,MODULE-IDENTITY. The OBJECT-TYPE macro is used to define managed objects.OBJECT-TYPE conveys both syntax and semantics of a managed object. Notification in SMIv2 is equivalent to trap in SMIv1.In SMIv1,trap is formally specified by an ASN.1 macro,TRAP-TYPE.In SMIv2,notification is specified by an ASN.1 macro,NOTIFICATION- TYPE,and conveys both its syntax and semantics
6.3 SNMPv2 Structure of Management Information There are several changes to SMI in version 2, as well as enhancements to SMIv2 over that of SMIv1. The SMIv2 [RFC 1902] is divided into three parts: module definitions, object definitions, and notification definitions. The module definitions describe the semantics of an information module and are formally defined by an ASN.1 macro, MODULE-IDENTITY. The OBJECT-TYPE macro is used to define managed objects. OBJECT-TYPE conveys both syntax and semantics of a managed object. Notification in SMIv2 is equivalent to trap in SMIv1. In SMIv1, trap is formally specified by an ASN.1 macro, TRAP-TYPE. In SMIv2, notification is specified by an ASN. 1 macro, NOTIFICATIONTYPE, and conveys both its syntax and semantics
SNMP Manager SNMP Agent SNMP Manager APDU SNMP Agent Application Application isenbe-ing-6 nbeJ-jes isenba-a6 senba-xeu-je6 isenba-ying-e6 isenba-jes den-dwus SNMP SNMP PDU SNMP UDP CLNS IP IP DLC DLC PHY PHY Physical Medium CLNS=Connectionless-Mode Network Service UDP User Datagram Protocol DLC Data Link Control igure 6.3 SNMPv2 Network Management Architecture on Multiple Transport Domains