Mumbai University > Electronics and Telecommunication > Sem8 > Wireless Networks

Marks: 10 M

Year: Dec 2013, Dec 2014

1. imode

i. It is a proprietary mobile ISP and portal service from NTT Do Co Mo, Japan, with about 50 million subscribers.

ii. It allows application/content providers to distribute software to cellular phones and also permits users to download applets.(e.g. games)

iii. It uses cHTML(compact HTML) as page description language. The structure of cHTML means that the user can view traditional HTML and imode sites can be inspected with ordinary web browsers.

iv. It uses ‘Personal Digital Cellular-Packet (PDC-P)’ and subset of HTML3.0 for content description.

2. Packet switching in imode

i. imode uses packet-switched technology for wireless part of communication. Wired part is carried over TCP/IP.

ii. The messages are divided in small blocks called packets. Header is added which contain address and control information.

iii. This allows multiple communications to be carried on a single channel with low cost.

iv. Dopa, Do Co Mo’s dedicated data communications service, offer connections to LAN and ISPs.

v. The users are charged per packet of downloaded information.

3. Imode network configuration

i. PDC is digital system for portable and automobile telephones. imode has packet communications functions added and integrated into PDC.

ii. Do Co Mo has developed a data transmission protocol specific to imode which is used wih PDC-P System.

iii. The PDC-P network includes a ‘mobile message packet gateway (M-PGW)’ to handle conversions between two protocol formats.

iv. imode server is a regular web server which can reside at NTT Do Co Mo or at enterprise.

4. Security

i. imode relies on Internet security as provided by SSL/TLS.

ii. Imode phones are pre-configured with root collision avoidance keys from public key infrastructure.

iii. This allows server side authenticated SSL session between imode device and imode server hosted by enterprise.

iv. But there is no capability of handling client-side certificates which means non- repudiation is not possible.

Fig4. imode wireless networking environment