A variety of applications can make use of the ESRO protocol. In this section we mention and provide references to a number of ESRO based applications. Based on the broadness of their usage and intended audience, we categorize them as either ``Horizontal Applications'' or ``Vertical Applications.''
Various efficient horizontal applications have been developed or are being developed using ESRO. These include:
A brief description of each is provided below.
One of the efficient application layers built on top of ESRO is called Efficient Mail Submission & Delivery, or EMSD. EMSD is the component of LEAP that addresses the Mobile Messaging application.
EMSD is highly optimized for the submission and delivery of short (typically 4 kilobytes or less) Internet e-mail messages, and is therefore extremely well suited to the wireless environment. EMSD improves on existing messaging protocols by optimizing the exchange between the server and the end-user device, both in terms of the number of bytes transferred, and in terms of the number of transmissions. For more information on EMSD see the article EMSD: The LEAP E-Mail Component within The LEAP Manifesto, or visit the EMSD website at http://www.emsd.org/.
The Efficient Hyper Text Delivery (EHTD) layer is a hypertext transfer protocol which is optimized for the efficient transfer of short markup pages. EHTD is the component of LEAP which facilitates web browsing. Along with EMSD, EHTD also benefits from the reliable efficient services of ESRO. A multiplicity of efficient markup languages can be used in conjunction with EHTD. Development of the EHTD protocol is currently in progress.
Various other efficient application protocols are either under development, or anticipated for future development. One of these is the Efficient Dictionary protocol, or E-DICT, which will enable efficient access to dictionaries and other lookup data structures. A starting point for the E-DICT protocol is currently being created. In developing E-DICT, we intend to build on the existing work already done in the context of the DICT protocol.
We anticipate that additional protocols will be needed for a variety of future applications, not all of which can be foreseen at this time. These applications will include such things as efficient implementations of ESRO-based instant messaging, chat, white pages, and others.
Various efficient vertical applications have been developed or are being developed using ESRO. These applications include:
There are a set of common architectural characteristics to most of these vertical applications. These common characteristics are illustrated in Figure 1. In this figure, the box labeled ``Thin Reliability Layer'' represents the position of ESRO.
