Making the Internet Mobile Challenges & Pit Falls(difficult)

          The major technology challenges making specific reference to those that, the largest abstraction for deploying application in wireless environment. The TCP/IP support fir connection to the internet. Today average cellular phone user jump into the mobile internet.

          The wireless communication type difficult to make statement they will apply to thai network. For example : Packet base network have connection characteristics the differ from those of cir-cute switch network.

Wireless Network Characteristics:

• Latency
• bandwidth  run time cost
• Error rate and unreliability.  

 Latency :

     The amount of time requirement for a message to travel between two points in the network. Wireless network type have considerably longer latency time then their lower connection. The message deliver via SMS over the GSM system has been know to take several minutes.

     The transport protocol some apple will lost packet and to need to re-transmit. 

     The effect of the latency on application :

              Calculation of the expected response time for an application behavior. The wire line network most pocket arrive in order. But wireless. network some packet will lost.

The effect of latency on transport protocol :

=> The wireless network latency also effect for transfer protocol such as TCP/IP.

=> The major error recovery protocol implemented in TCP.

      1. TCP behavior with high latency environment.The TCP sends two basic acknowledgement to received.

           => ACK - The data deliver correctly in sequence order.

          =>  DUPACK - Data deliver correctly but not sequence order. 

Improving TCP Behavior:

       Major implementation of TCP stacks in the market place.The specific protocol solution for the mobile environment will be required.

Bandwidth & Run-time Cost :

=> The bandwidth is the speed of the data network measure bit per second.

=> The higher the network band with greater the protocol of more data in a different period.

=> The digital network proved to be much more reliable network and must fast data rate have been achived.

The following digital Network : 

Network                                             Data service rate 

GSM                                                     9600 bps.

CDMA                                                 14400 bps

GPRS                                                   115 kbps.

EDGE                                                   384 kbps.

UMTS                                                   2 mbps. 

=> The measuring of the cost will be amount of time and amount of data transferring content.

Error Rate & Unreliability :

1. Bit Error Rate : 

    The ratio of corrupted bit to total bit transmitted. The mobile internet usually involve both wire and wireless links.The application and rate from both media.

2. Communication Error :

    => Data performance over the wireless network is also affected by the connectivity from network operator to the internet. 

   => The user is mobile a car moving at 100 km/hr. In that case the data may be disturbed and arriving the inform different time interval.

   => The network transport protocol correct these error.

3. User Error:

   => More relevant source of error include those that result from a user action.

         For example: Closing application cleanly in unnatural to a own user, simply hang up and turn off the phone.So application should to be this into the account.

  => The re-engineering this application times responsible algorithm and policy loop need to be employed.

Security Implementation for wireless devices:

Service Requirement :

                 To build wireless application developer must consider as follows :

1. Scalability : 

2. Roaming and network services

1.Scalability:

     The PC environment may expect client server ratio of 100 of client to one sever.The wireless device is a mobile phone, the ratio to scallop to millions of client for each server. This scal implies the need for larger faster content server network router wireless network environment. The scalability is particularly significant for the application written when considering managing & controlling the client environment.

2. Roaming and network services :

     The wireless network service provided control the available facility and services to different service provider. Roaming may differ romantically from those available in some places. The user may transparently swap service provider the issue must be consider by application developer. The W3C define standard for passing about capable from parties.