WIRELESS TRANSACTION PROTOCOL WTP By Pathfinders WHAT IS

WIRELESS TRANSACTION PROTOCOL (WTP) By Pathfinders

WHAT IS WAP? § Wireless Application Protocol § Standard created by wireless and Internet companies § Enables internet access from a cellular phone Enables applications to scale across variety of transport options and device types §

PROTOCOL STACK FOR WAP Application Layer (WAE) Other Services And Applications Session Layer (WSP) Transaction Layer (WTP) Security Layer (WTLS) Transport Layer (WDP) SMS USSD CSD IS-136 CDMA CDPD PDC-P Etc

WAP ARCHITECTURE WAP Gateway WMLScript WTAI Etc. Web Server WML Encoder WSP/WTP WMLScript Compiler Protocol Adapters HTTP CGI Scripts etc. Content WML Decks with WML-Script Client

WHAT IS WTP? § Light weight transaction oriented protocol § Runs on top of datagram service § Chops data packets into lower level datagram's § Concatenates received datagram's into useful data Operates above WDP to provide simple protocol suitable for low bandwidth mobile station §

HOW IT IS DESIGNED FORWIRELESS ENVIRONMENT § no explicit connection setup or tear down §optimized setup (data carried in first packet of protocol exchange) § seeks to reduce 3 -way handshake on initial request supports User acknowledgement or Stack acknowledgement option [acks may be forced from the WTP user (upper layer) default is stack ack] §

WTP TRANSACTION SERVICES WTP offers 3 classes of transactions services: • Unreliable one-way request (Class 0) • Reliable one-way request (Class 1) • Reliable two-way request/response (Class 2)

OPERATION OF CLASS 0 Initiator TR-Invoke/ Request Responder Invoke PDU (TID=N, TG, C=0, …) TR-Invoke/ Indication

BASIC OPERATION OF CLASS 1 Initiator TR-Invoke/ Request Responder Invoke PDU (TID=N, TG, C=1, …) TR-Invoke/ Indication Ack PDU (TID=N*) TR-Invoke/ Confirm

CLASS 1 – WITHU‘ SER’ ACKNOWLEDGEMENT Initiator TR-Invoke/ Request Responder Invoke PDU (TID=N, TG, C=1, …) TR-Invoke/ Indication Ack PDU (TID=N*) TR-Invoke/ Confirm TR-Invoke/ Response

BASIC OPERATION OF CLASS 2 Initiator TR-Invoke/ Request Responder Invoke PDU (TID=N, TG, C=2, …) TR-Invoke/ Indication Result PDU TR-Invoke/ Confirm TR-Invoke/ Request TR-Result/ Indication TR-Result/ Response Ack PDU TR-Result/ Confirm

CLASS 2 - WITH H ‘ OLD ON’ ACKNOWLEDGEMENT Initiator TR-Invoke/ Request Responder Invoke PDU (TID=N, TG, C=2, …) TR-Invoke/ Indication Ack PDU TR-Invoke/ Confirm Result PDU TR-Result/ Indication TR-Result/ Response TR-Invoke/ Request Ack PDU TR-Result/ Confirm

CLASS 2 - WITH U ‘ SER’ ACKNOWLEDGEMENT Initiator TR-Invoke/ Request Responder Invoke PDU (TID=N, TG, C=2, …) TR-Invoke/ Indication Ack PDU TR-Invoke/ Response Result PDU TR-Invoke/ Request TR-Invoke/ Confirm TR-Result/ Indication TR-Result/ Response Ack PDU TR-Result/ Confirm

WTP MANAGEMENT ENTITY § Interface between WTP layer and environment of device § Monitors the state of mobile environment § Deals with all the issues related to § Initialization § Configuration § Resources as they pertain to WTP layer

WTP FEATURES Provides reliable, efficient data transfer based on request/reply paradigm § § Supports selective re-transmission § Message oriented (not stream) § Supports Abort function § Supports concatenation of PDUs

MOBILE WWW

REFERENCES AND RESOURCES § Books - Understanding WAP § Official Website (specifications) - www. wapforum. org

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