Transport services and protocols o provide logical communication lication between app processes running on different hosts data link networ data link o transport protocols run in end systems o send side: breaks app network data link messages into segments physical passes to network layer o rcv side: reassembles segments into messages application passes To app layer networ data link o more than one transport protocol available to apps o Internet: tcp and UDP Transport Layer 3-4Transport Layer 3-4 Transport services and protocols  provide logical communication between app processes running on different hosts  transport protocols run in end systems  send side: breaks app messages into segments, passes to network layer  rcv side: reassembles segments into messages, passes to app layer  more than one transport protocol available to apps  Internet: TCP and UDP application transport network data link physical application transport network data link physical network data link physical network data link physical network data link physical network data link network physical data link physical