UDP:User Datagram Protocol [RFC768] INTERNET STANDARD RFC 768 J.Postel ISI 28 August 1980 User Datagram Protocol Introduction This User Datagram Protocol (UDP)is defined to make available a datagram mode of communication in the environment of protocol that the Internet underiying protocol. This protocol provides a procedure for application programs to send suarantond.co devero with a minimu of The streams of data should use the Transmission Control Protocol (TCP)[2]. Format 78 15162324 31 Source Destination Port Port Length Checksum data octet5·· Transport Layer:3-26
UDP: User Datagram Protocol [RFC 768] Transport Layer: 3-26
UDP:Transport Layer Actions SNMP client SNMP server application application 工 transport transport (UDP) (UDP) network(IP) network(IP) link link physical physical Transport Layer:3-27
SNMP server SNMP client transport (UDP) physical link network (IP) application UDP: Transport Layer Actions transport (UDP) physical link network (IP) application Transport Layer: 3-27
UDP:Transport Layer Actions SNMP client SNMP server UDP sender actions: application is passed an application- ap SNMP msg layer message transport determines UDP segment UDP SNMP msg (UDP) header fields values UDP network (IP) ■creates UDP segment network(IP) link ■passes segment to IP link physical physical Transport Layer:3-28
SNMP server SNMP client transport (UDP) physical link network (IP) application transport (UDP) physical link network (IP) application UDP: Transport Layer Actions UDP sender actions: ▪ is passed an application- SNMP msg layer message ▪ determines UDP segment header fields values ▪ creates UDP segment ▪ passes segment to IP UDPhh SNMP msg Transport Layer: 3-28
UDP:Transport Layer Actions SNMP client SNMP server UDP receiver actions: application receives segment from IP application ■checks UDP checksum transport SNMP msg header value P extracts application-layer (UDP) UDP SNMP msg message network(IP) demultiplexes message up link to application via socket link physical physical Transport Layer:3-29
SNMP server SNMP client transport (UDP) physical link network (IP) application transport (UDP) physical link network (IP) application UDP: Transport Layer Actions UDP receiver actions: SNMP msg ▪ extracts application-layer message ▪ checks UDP checksum header value ▪ receives segment from IP UDPh SNMP msg ▪ demultiplexes message up to application via socket Transport Layer: 3-29
UDP segment header 32 bits source port dest port length checksum application length,in bytes of data UDP segment, (payload) including header data to/from UDP segment format application layer Transport Layer:3-30
UDP segment header source port # dest port # 32 bits application data (payload) UDP segment format length checksum length, in bytes of UDP segment, including header data to/from application layer Transport Layer: 3-30