1. Department of Information Engineering 1 M-commerce Wireless Application Protocol (WAP) –http://www.webproforum.com/wap/index.html –provides web-like services in wireless domain To operators –improving existing services better interface to voice mail –new value-added services banking, stock info, entertainment info

2. Department of Information Engineering 2 M-commerce To content providers –Using the same model as the Internet –Applications are written in tag-based wireless markup language (WML), which is a subset of extensible markup language (XML) –100 million WAP To end users –easy access to information and services such as stock prices, news, weather, and travel information through their mobile devices

3. Department of Information Engineering 3 M-commerce –expects to have an even far reaching impact to society than Internet Why? –Because not everybody can use a computer to access Internet –but everybody know how to use a mobile phone mobile phone has the potential to capture 75% of the population

4. Department of Information Engineering 4 M-commerce WAP –is a global standard for mobile network –founded in 1997 by companies like Ericsson, Nokia, and Motorola –similar to the Internet model, the wireless device contains a microbrowser, while content and applications are hosted on servers. –applications are written in tag-based wireless markup language (WML)

5. Department of Information Engineering 5 M-commerce WAP is similar to HTTP/TCP/IP –but TCP is inefficient over mobile networks –so WAP has its own transport layer (like TCP) WAP phone cannot be connected to web directly! –similar to HTTP/TCP/IP only in concept, it has different implementation !!

6. Department of Information Engineering 6 M-commerce Because WAP uses different format for its data, packet sent by WAP will not be understandable by TCP/IP based machines –it is like document produced by Microsoft and Apple, the formats are different using the same analogy, if Microsoft Word wants to read a document in Apple format, it needs to translate the document format

7. Department of Information Engineering 7 M-commerce WAP phone users can only access Internet via a WAP Gateway –basically a machine that translate the WAP packet format to IP format The incompatibility is probably by design !! –less competition! –Operators cannot use IP-based routing equipment, they must buy it from Ericsson, Nokia, Motorola,... For end users –currently can only access network provided by their service providers

8. Department of Information Engineering 8 M-commerce Competition for WAP protocols –subscriber identity module (SIM) toolkit use of SIMs or smart cards Windows CE –from Microsoft JavaPhone –Sun Microsystems –embedded in a Java virtual machine on the handset NTT Docomo –huge customer base in Japan –support IP, can access to Internet directly

9. Department of Information Engineering 9 Future Third generation mobile communication W-CDMA (wideband CDMA) –1.5 M bits per second Applications –mobile multimedia –phone may attach a video camera video conferencing sends picture to home while you are traveling

10. Department of Information Engineering 10 Not everything is rosy Satellite phone Different from mobile –uses a large number of satellite to cover the entire world –can make call anywhere as long as there is a satellite above you top of Everest In contrast, cellular phone –uses a large number of base stations to cover a city –can only make call when there is a base station nearby

11. Department of Information Engineering 11 Recent disaster Satellite phone –One of the biggest blunder ever !! Demise of Motorola Iridium project –a satellite network 66 low-order satellite covers the entire globe –only in operation for one year DON’T buy those satellite phone in Mong Kok –easily identifiable by its large size

12. Department of Information Engineering 12 Lab session - application protocol Hyper Text Transfer Protocol (HTTP) telnet www.cuhk.edu.hk 80 GET http://www.ie.cuhk.edu.hk/index.html HTTP/1.0

13. Department of Information Engineering 13 SMTP (Simple Mail Transfer Protocol) SMTP - an ASCII protocol for transferring emails from host to destination`s mail server, e.g., to send a mail to me: > telnet ie.cuhk.edu.hk 25 ;TCP connection to mail daemon 220 eng.ie.cuhk.edu.hk ESMTP ;reply from ie mail server MAIL FROM: abc@tom.com 250 abc@cse.cuhk.edu.hk... Sender OK ;server reply RCPT TO: mchang@ie.cuhk.edu.hk 250 mchang@ie.cuhk.edu.hk... Recipient ok DATA 354 Enter mail, end with ``.`` on a line by itself... email body. QUIT

14. Department of Information Engineering 14 SMTP (Simple Mail Transfer Protocol) Mail bomb –large volume of junk mails intended to flood the buffer space of the mail server –sender's name is easy to disguise mail server does not verify the sender address “MAIL FROM: “ field, you can put it anything you like –it is still possible to trace the IP address of the sender`s station from the system's log

15. Department of Information Engineering 15 POP3 (Post Office Protocol) (RFC1225) To fetch mail from a remote mailbox –incoming mails are stored in the mail server –> telnet ie.cuhk.edu.hk 110 +OK QUALCOMM Pop server ready user mchang +OK Password required for mchang pass ******** +OK mchang has 2 message(s) (1351 octets)

16. Department of Information Engineering 16 POP3 (Post Office Protocol) (RFC1225) list +OK 2 messages (1351 octets) 1 869 2 482 retr 1 +OK 869 octets Received: from...... dele 1 +OK Message 1 has been deleted quit