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This document discusses problems with HTTP and HTML for mobile devices and proposes solutions. HTTP was designed for high-bandwidth, low-delay connections and results in large headers, uncompressed content transfers, and overhead from separate TCP connections for each page item. Caching is also often disabled on dynamic pages. HTML assumes desktop computers rather than mobile constraints. Solutions proposed include image scaling, content extraction, new protocols, push technologies, and enhanced caching through client and network proxies.
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- 2. World wide web ● ● Problems encounters the web applications used in a mobile and wireless environment. Basic intro about HTTP – It is a stateless , lightweight , application level protocol for data transfer between servers and clients. – HTTP transaction consists of HTTP request issued by the client and and HTTP response from a server
- 3. HTTP ● ● ● ● It supported only simple caching mechanisms to avoid unnecessary retransmission. Caches may be located anywhere between server and client. Each client maintains a cache locally to minimize delay when jumping back and forth on web page. Application must not cache page beyond expiration.
- 4. HTTP problems ● Bandwidth and delay – It is designed with high bandwidth/low delay connections in mind. – HTTP header is quite large and redundant. – Server transfer content uncompressed. – TCP connection is used for each item on web page, huge overhead with each item.(three way handshack and four way disconnection) – Requires an additional request for DNS.
- 5. HTTP problems ● Caching – It is usefull in many cases, often disabled by content provider (number of clicks on a page). – Present-day pages contain dynamic objects that cannot be cached. – Page often created dynamically depending on the type of browser,client harware,client location etc. – Can't merge static content with dynamic remainder page.
- 6. HTML ● ● ● ● It is designed for standard desktop computers connected witht a fixed wire. Having high-resolution, mouse,sound system and large hard disk. Wireless devices having low-resolution, limited user interference, low performance CPUs Pages are degined for nice presentation of content, not for efficient transfer of this content.
- 7. HTTP and HTML solutions ● Image scaling – ● Scale down to fewer colors, lower resolution or just title of picture. User decide to zoom or download. Content transformtion – – ● Many application documents availabe is certain format (pdf, post script etc.) Convert and transfer. Content extraction/semantic compression – Headline or keyword extracted from a document
- 8. HTTP and HTML solutions ● Special language and protocols – – ● Replace HTML Like introduction of Handheld Device Transport Protocol (HDTP) and the Handheld Device Markup Language (HDML) Push technologies – Instead of pulling content from server , the server could push content to a client. – Avoid overhead of connection on each object
- 9. System Architecture ● Integrated browser enhancement – – ● Integration of caching into web browser. Does't perform pre-fatching of pages but stores already transferred contents. Additional application support browsing – ● Pre-fatching of content, caching and disconnected service Client proxy as browser support – Browser access the web server through the client proxy. – Proxy can perform pre-fetch and cache content.
- 10. System Architecture ● Network proxy as browser support – – ● proxy support mobile client on the network side Further enhancement using ITCP. Client and network proxy as browser support – ● Combined client and n/w proxy Client and nerwork proxy with special transmission protocol – Client , n/w proxy with special transmission protocol
- 11. Wireless Application Protocol(version 1.x) ● ● ● WAP Forum was founded in June 1997 by Ericsson, Motorola, Nokia and Unwired Planet In 2002, the WAP forum together with open mobile architecture forum formed open mobile alliance. Objective – To bring diverse internet content and other data services to digital cellular phones and other wireless, mobile terminals
- 12. Design Consideration ● ● ● Interoperable – alowing terminals and s/w from different vendors to communicate with n/w from different providers. Scaleable – should scale with customers needs and number of customers Efficient – provision of QoS suited to the wirless and mobile n/w ● Reliable ● Secure
- 13. Architecture