Fixed wired network: Traditional distributed computing.
Fixed wireless network: Wireless computing.
Wireless network: Mobile Computing.
Vertical : tracking , point of sales
Horizontal : mail application , filter information provision
new massive markets in conjunction with the Web
Mobile Information Appliances - combining personal computing and consumer electronics
Mobile and Wireless Computing & applications
Mobile Computing Architecture Infrastructure-based mobile platform A general architecture of an infrastructure-based mobile platform high-speed wired network Base Station Base Station Base Station Wireless LAN Cell 2kbps - 15 mbps Wireless Radio Cell 9kbps-14 kbps Wireless Ethernet Cell Mbps - Gbps
Mobile Ad-Hoc Network (MANET):
In a MANET , mobile units do not need to communicate via a fixed network such as Bluetooth.
In a MANET , mobile units are responsible for routing their own data
MANET must be robust enough to handle changes in network topology.
Such as arrival or departure of mobile unites.
Sample applications for MANET application
Battle information sharing
Characteristics of (MANET):
Frequent network partitions.
Centralized control is difficult .
Mobile Computing Architecture: Infrastructure-less Mobile Platform (MANET )
MANET can fall under Peer-to-Peer architecture .
Peer-to-Peer : means that mobile units is simultaneously a client and server .
Kinds of Peer-to –Peer :
Hybrid P2P Network : Central server can provide the information to all peers (Napster)
Fully p2p network : No central servers
First generation : routing and querying through broadcasting ,
Causing flooding in the network .
Second generation : routing and querying are based on distributed hash tables
Mobile Computing Architecture:
Query & Transaction processing
Hardware problems are more difficult.
Limited & intermittent of Connectivity .
Battery Life .
Changes in network topology.
Wireless Transmission Speed.
Characteristics of Mobile Environments
High communication latency
Increases the time to service each client request
The server can handle fewer clients.
broadcasting data whenever possible
Intermittent wireless connectivity
unIntentional :signals cannot reach,
intentional :takeoff of an airplane prerogatives
limited battery life
Changing client location
Characteristics of Mobile Environments cont
To compensate for high latencies and unreliable connectivity
Caching frequently used data on the mobile device.
Increasing data availability and response time
Organize data by using the Cluster
A client may be unreachable because handoff
Proxies for unreachable (proxy can cache updates intended for the server
Proxy automatically forwards these cached updates to their ultimate destination
MDB can be distributed under two possible scenarios:
The entire database is distributed mainly among the wired components
A base station or fixed host manages its own database
query and transaction management of mobile environments.
The database is distributed among wired and wireless components
Data management responsibility is shared among BS or FH and mobile units.