Plug-and-play technologies have made our use of personal computers easier. These technologies simplify the installation of new electronic components and input/output devices: adding a new disk drive, LAN card or printer has been automated through autodetection of the new equipment and easy-to-follow procedures for driver installation. Now service-discovery technologies extend the notion of plug-and-play to the network. Reaching beyond the install process, service discovery allows an office service to find and then bind with network-attached office equipment.
Service-discovery technologies provide a standard method for applications, services and devices to describe their capabilities to others and to determine the capabilities of the networked office products they encounter. Service discovery also enables applications, services and devices to search for other networked office products that provide a particular capability. Advanced service-discovery offerings request and establish interoperable sessions with office products that they find, allowing for the utilization of discovered capabilities.
The Salutation architecture is one such technology that supports print, fax and scan device types. Users can locate input/output devices, providing access to networked digital office equipment. A computer user can locate a device that meets specific requirements and then start a process that uses that device to monitor the job's progress. For example, the user may need a print device that supports high-resolution color, multiple input sources and document finishing. Implementations of Salutation can locate a network printer that supports those needed functions and then bind to that printer, directing a print job to it. Salutation can also notify the user if at any time manual intervention is needed at the print device.
Tools track paper
Essentially, Salutation addresses office fax machines, scanners, printers, multiple-output copiers (for which the neologism "mopier" has been fabricated) and multifunction office equipment with a single protocol. Those devices become integral tools for tracking paper on the information highway. Providing support for single-function and multifunction hard-copy devices, those solutions extend document management to the information worker.
The architecture was created to solve the problems of service discovery and utilization among a broad set of appliances and equipment and in an environment of widespread connectivity and mobility. It provides a standard method for applications, services and devices to describe and to advertise their capabilities to other applications, services and devices and to find out their capabilities. And, it enables applications, services and devices to search other applications, services or devices for a particular capability and to request and establish interoperable sessions with them to utilize their capabilities.
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Given the diverse nature of target appliances and equipment in an environment of widespread connectivity, the architecture is independent of processor, OS and communication protocol and allows for scalable implementations, even in very low-price devices.
Basically, the Salutation architecture defines an entity called the Salutation Manager that functions as a service broker for applications, services and devices called a networked entity. The Salutation Manager allows networked entities to discover and utilize the capabilities of other networked entities.
A networked entity may be a service provider. The service registers its capability with a Salutation Manager. A networked entity may be a service user, called a client. The client discovers services and requests to use them through a Salutation Manager. A networked entity may serve as a client or a service or both.
Service-discovery technologies need to provide four primary functions. These include service discovery, an availability response, device-driver retrieval and service session management. Service discovery needs to provide for the discovery of networked products through a client-server model. In this model, the client sends a request to the network with a definition of the service capabilities that it needs. Servers compare that request with the services they provide and respond accordingly. Clients can make the request at several levels.
A request may be structured to determine all the capabilities of a service. This is useful for a network directory. The directory may automatically discover the capabilities of new equipment and build the appropriate directory records. That technique can automate the installation process for new equipment, easing the requirements on the network administrator and reducing the time between plugging the device into the network and actually being able to use it.
In addition, a request may be structured to discover services of a specific class. A print server may use that technique to locate all printing devices and determine their functionality. Functions such as supported page size, document finishing and print resolution may be logged and jobs routed appropriately. A request may also be structured to find a service matching a specific set of capabilities.
Once a client has found the service it needs, the service-discovery protocol needs to determine if the service is ready for use. That saves users from attempting to use printers that are low on toner or are down for preventive maintenance.
Using Salutation architecture, the availability check is structured around a timed-based required response. The client instructs the server to respond within a certain time period. If the server does not, the client assumes the server is unavailable and may use session management to determine the reason.
Advanced service-discovery technologies provide common message-management and job control, allowing for consistency across diverse network environments. Although that function is not needed if the client supports the form and format of the service, it needs to be available when a mismatch occurs.
The architecture's "Find-and-Bind" technology allows a device or network server to internally store its device drivers. Find-and-Bind also allows the drivers to be automatically located by and downloaded to a user's Salutation-enabled computer or information appliance. That eliminates the need to manually find the media on which the device driver was originally shipped and it completely automates the device-driver installation process.
Mobile technologies increase the need for service discovery that is not tied to a specific environment or platform. As mobile workers roam into geographically and technologically different network environments, their mobile information appliances such as laptops, handheld PCs and PDAs will have to be able to discover and gain access to the services provided by those various information networks. Likewise, with a compatible and adequately proficient service-discovery technology at the office server, the server can determine the characteristics of the mobile information appliance that has entered the network environment. The server can tailor interactions with the appliance based on the mobile computer's display size, color resolution and graphic characteristics. If desired, applications that are suitable for the mobile device's processor and operating system can be downloaded to it. User-interface characteristics can also be altered to meet the device's characteristics.
To complement existing office automation products that utilize Salutation, the Salutation Consortium is developing examples of service-discovery implementations for Windows CE, PalmOS and Java. Initially running over Infrared protocol, those examples are readily portable to other protocols. Products currently using the Salutation service-discovery techniques have been shipping for over two years.