The pros and cons of fat and thin mobile clients

Assessing the availability of a network connection and computing power required may help with purchasing decisions. by Mukund Balasubramanian

The growing prevalence of wireless networks has fueled an increase in wireless hand-held devices. Market research and analysis firm International Data Corporation (IDC) predicts that worldwide shipments of smart phones will more than double, from 164.7 million units this year to 363.2 million units by 2012.

These mobile hand-held devices typically operate as thin clients or fat clients. Fat and thin client platforms each have advantages and disadvantages, so when choosing between fat and thin clients, desired applications, user experience, performance and return on investment are the key considerations when making a purchasing decision.

Users should first consider where and how the device will be used. Thin clients require a constant connection with the server, since that is their source for updating and obtaining data, while fat clients are capable of storing applications and data on the device when a connection to the server is unavailable.

Fat clients typically have one to three layers of application code and can operate independently from a server. Fat clients support working in a disconnected or occasionally connected mode, with the option of client side application logic and local persistence. Fat client platforms are designed for applications that require in-the-field data collection.

A fat client can accept input and store data until connectivity with the server can be established; the data can be synchronized with the server in a wired or wireless mode later. This allows the user to continue working even if he is out of contact with the server.

Fat client applications are general used for personal information management software (e.g., e-mail, SMS, calendaring, contacts, tasks). An insurance agent, for example, can update photos collected in the field and synchronize it to a server later. A health care professional could log in data during patient visits and synchronize with the server periodically. Workers in the field can log inventory while offline or in areas with no wireless connectivity available.

offline and online use;
reduced over the air (OTA) network costs;
wired and wireless modes;
prolonged battery life due to offline usage;
a wide variety of applications available; and
end-to-end security solutions possible on client and server side.

Some disadvantages of fat client solutions include:

purchasing and maintaining applications on numerous devices increases costs;
some platforms have limited application options;
distribution of latest updates can be difficult to coordinate;
need to create back-end services to support the use of access points specific to a phone or network; and
device and data security is required, since the device stores data.

Thin client devices have become a popular alternative. A thin-client system consists of a server and a client that communicate over a network using a remote display protocol. A thin client approach may be more suitable in the context of accessing Web applications that have a known user base. This often calls for redesigning the presentation layer of existing Web sites to suit hand-held device form factors and download size restrictions.

The use of thin clients in mobile commerce allows digital content to be purchased on the Web, behind a secure enterprise firewall. Thin clients can be used to make mobile payments, enabling users, for example, to use the mobile phone as a wallet, transferring funds securely over the air. Multimedia content (e.g., audio, video, photos, RSS feeds) subscriptions from multiple sources can be streamed and shared from a hosted environment.

The thin client supports the use of location-based services, which allow users to gather information specific to a location in real time. Thin clients also support message-based services using SMS and push alerts for immediate notification.

The thin client design offers a variety of benefits:

supports existing Web sites;
if the device is lost or stolen, it can be disabled remotely;
no software deployment necessary on client side;
updates take place over the air;
all processing and management occurs at the server, so the mobile device has fewer points of contact with processing activity;
offers vendor-neutral, standard integration with third- party Web 2.0 sites (e.g., Flickr, Facebook, MySpace); and
data collected can be uploaded immediately to Web 2.0 communities.

Some of the disadvantages of thin client applications include:

high-performance, scalable servers required;
high bandwidth must be available for multimedia applications;
additional thin clients place more demands on the server;
if the network is down, the thin client cannot access the server and required processing power; and
scaled screens and less robust applications.

Mukund Balasubramanian is CTO of Photon InfoTech, Tamil Nadu, India.

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