tructure 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 make it possible for third-party parsers to be used in processing the XML protocol message. GET Message with XML: <getenvp getenvp to= 'host' xmlns=`reqinfo:client' xmlns: getenvp= <getenvp: Header> <getenvp:getenvp from=`host' 'stream-id' kmlns=`reqinfo:client' xmlns: getenvp= </getenvp: Header> <getenvp: Body> <iq type='get to='mib@host id=`query-id'> <query xmlns=`reqinfo:iq:shelf-6.card-2.status'/> </iq> </getenvp : Body> </ getenvp getenvp > GET-NEXT message with XML: <getenvp getenvp to='host' xmlns=`reqinfo:client' xmlns getenvp= - URI , <getenvp: Header> <getenvp:getenvp from=`host' 'stream-id' xmlns=`reqinfo:client' xmlns:getenvp= URI </getenvp: Header> <getenvp:Body> <iq type='get-next to= 'mib@host' id= 'query-id'> <query xmlns=`reqinfo