.Connection Oriented Transport Protocol Mechanisms Logical connection Establishment Maintenance termination Reliable . TCP .Reliable Sequencing | William Stallings Data and Computer Communications Chapter 17 Transport Protocols Connection Oriented Transport Protocol Mechanisms Logical connection Establishment Maintenance termination Reliable . TCP * Reliable Sequencing Network Service Assume arbitrary length message Assume virtually 100% reliable delivery by network service . reliable packet switched network using . frame relay using LAPF control protocol . IEEE using connection oriented LLC service Transport service is end to end protocol between two systems on same network * Issues in a Simple Transprot Protocol Addressing Multiplexing Flow Control Connection establishment and termination * Addressing Target user specified by: User identification Usually host, port Called a socket in TCP Port represents a particular transport service (TS) user Transport entity identification Generally only one per host If more than one, then usually one of each type Specify transport protocol (TCP, UDP) Host address An | William Stallings Data and Computer Communications Chapter 17 Transport Protocols Connection Oriented Transport Protocol Mechanisms Logical connection Establishment Maintenance termination Reliable . TCP * Reliable Sequencing Network Service Assume arbitrary length message Assume virtually 100% reliable delivery by network service . reliable packet switched network using . frame relay using LAPF control protocol . IEEE using connection oriented LLC service Transport service is end to end protocol between two systems on same network * Issues in a Simple Transprot Protocol Addressing Multiplexing Flow Control Connection establishment and termination * Addressing Target user specified by: User identification Usually host, port Called a socket in TCP Port represents a particular transport service (TS) user Transport entity identification Generally only one per host If more than one, then usually one of each type Specify transport protocol (TCP, UDP) Host address An attached network device In an internet, a global internet address Network number * Finding Addresses Four methods Know address ahead of time . collection of network device stats Well known addresses Name server Sending process request to well known address * Multiplexing Multiple users employ same transport protocol User identified by port number or service access point (SAP) May also multiplex with respect to network services used . multiplexing a single virtual circuit to a number of transport service user charges per virtual circuit connection time * Flow Control Longer transmission delay between transport entities compared with actual transmission time Delay in communication of flow control info Variable transmission delay Difficult to use timeouts Flow may be controlled because: The receiving user can not keep up The receiving transport entity can not keep up Results in buffer filling up * Coping with Flow Control Requirements (1) Do nothing Segments that overflow
