eir own usage and semantics to work with "Report" PDU in SNMPv2. SNMPv2 mainly supports five transport services for transferring management information. This association of SNMPv2 with a transport service is referred to as snmpDomains and is described in RFC 1906. The domains are: snmpDomain Description snmpUDPDomain This corresponds to SNMPv2 over UDP (User Datagram protocol). For telecom management purpose UDP is the most popular transport service used with SNMP. snmpCLNSDomain This corresponds to SNMPv2 over OSI (open systems interconnection). This domain uses a ConnectionLess Network Service (CLNS). snmpCONSDomain This corresponds to SNMPv2 over OSI, similar to snmpCLNSDomain. This domain uses a Connection Oriented Network Service (CONS). snmpDDPDomain This domain corresponds to SNMPv2 over DDP (datagram delivery protocol). DDP is AppleTalk equivalent of UDP (and IP). snmplPXDomain This domain corresponds to SNMPv2 over IPX (Internetwork Packet Exchange) protocol. Mapping of SNMP over IPX is used in Novell NetWare environments. Fundamentals of EMS, NMS and OSS/BSS In-spite of several advantages of the SNMPv2 over its predecessor SNMPv1, there still were few unmet goals on security and administrative framework in its recommendations that resulted in SNMPv3. The major drawback of SNMPv2 was the lack of confidentiality. The request message from the origin and the response message from the destination were both not encrypted before transmission. Any third-party application could intercept the message and decode it. Introduction of encryption and several other security features is discussed in the next section. 14.4 SNMPv3 The five most important RFCs of SNMP Version 3 are: 1. RFC 3411: An architecture for describing SNMP management frameworks: This document is intended to provide details of the SNMPv3 management framework. It clarifies most of the terms that are used in the RFC docu- ments for SNMPv3. It provides an introduction to multiple logical con- texts and defines the user as an identity. The RFC also incl