to inline with what is used conven- tionally with SNMP. 18.5 Mapping with SNMP Since the reader is already familiar with SNMP, which was handled in much detail in some of the preceding chapters, the capability of XML protocol is analyzed in this chapter by showing how we can achieve the functions in SNMP using the XML protocol. This is followed by looking at some of the XML-based protocols like SOAP and NETCONF in more detail. To start with mapping of functions for SNMP, the first requirement would be binding with UDP (user datagram protocol). This will not be a problem as XML protocol can bind with UDP and is not coupled to a specific transport protocol (see Figure 18.1). The main difference here is that XML schema is used instead of the ASN.1 structure and the SNMP PDU is replaced with XMLP message envelope. Application layer Port 80 Service access point Transport layer Service access point Network layer Figure 18.1 Protocol binding with UDP. Fundamentals of EMS, NMS and OSS/BSS 18.5.1 Messaging The five basic messages that are used in SNMP and needs to be available in a replacement protocol are GET, GET-NEXT, GET-RESPONSE, SET, and TRAP. The example here is for binding with UDP, SO the connection details needs to be explicitly provided in the namespace of XMLP envelope. 1. GET and GET-NEXT message: In SNMP these messages are used by the manager to request specific information from the agent. The header, which is optional, gives the identification of the sender. The "host" in the header corresponds to where the information needs to be sent. The URI will be used while sending the envelope to the packet network. Header can also be used for authentication and encoding. The body contains the actual request to be performed. In the specific example used here, the "Body" of the envelope is used to query the status of a card in a specific shelf. It can be seen that the XML protocol mes- sage is easier to read and interpret compared to the SNMP message. The tags like <getenvp: Header> and <getenvp:Body> in the message m