Q17Mobile Computing
Question
4 marks
What is WAP? Explain the WAP protocol stack in brief.
Answer
A critical mathematical breakdown of the WAP Architecture. Details how the protocol stack violently compresses and optimizes internet data (HTTP/TCP) into lightweight binary protocols (WSP/WTP) to prevent catastrophic battery drain on 2G devices.
WAP is an obsolete but architecturally brilliant protocol designed for the brutal physics of early 2G mobile networks (9.6 kbps bandwidth, massive latency, and phones with 16KB of RAM). Sending raw HTTP over TCP to a Nokia 3310 would mathematically crash the phone. WAP completely reinvented the internet stack specifically for the wireless domain.
The stack mathematically mirrors the OSI model but is aggressively optimized for binary compression.
- WAE (Wireless Application Environment): The absolute top layer. It replaces HTML with WML (Wireless Markup Language) and WMLScript. It dictates how the micro-browser violently renders "Decks" of data on a tiny screen.
- WSP (Wireless Session Protocol): The mathematical replacement for HTTP. It provides a binary-encoded version of HTTP 1.1, violently stripping out massive text headers to crush the payload size. It supports session suspension (if a call interrupts data).
- WTP (Wireless Transaction Protocol): A lightweight, message-oriented protocol. It completely abandons the catastrophic three-way handshake of TCP, providing reliable request/response execution with exactly ONE acknowledgment, slashing latency.
- WTLS (Wireless Transport Layer Security): The mobile equivalent of SSL/TLS. It provides brutal cryptographic encryption (RSA, ECC) but is mathematically optimized to use minimal CPU cycles to save battery.
- WDP (Wireless Datagram Protocol): The adaptation layer. It mathematically interfaces the upper WAP stack with whatever physical bearer network is underneath (GSM, CDMA, CDPD), acting essentially like UDP.