10. Lic. Jorge Guerra G . Sistemas distribuidos Un sistema distribuido es una colección de computadoras independientes que aparecen ante los usuarios del sistema como una única computadora Tanenbaum Un sistema distribuido es aquel en el que los componentes localizados en computadores, conectados en red, comunican y coordinan sus acciones únicamente mediante el paso de mensajes Coulouris Otras definiciones
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13. Lic. Jorge Guerra G . Sistemas distribuidos Características de los Sistemas Distribuidos
39. Paradigma Cliente-Servidor Lic. Jorge Guerra G . Client Server know-how Servidor tiene todo: el know-how, el procesador y los recursos Cliente necesita inteligencia para descubrir al servidor que provee el servicio que se necesita.
41. Paradigma Código-por-demanda Lic. Jorge Guerra G . Server know-how Client Cliente tiene el procesador y los recursos. No tiene el know-how Servidor envía el know-how sobre el cliente .
44. Paradigma Código-por-demanda Lic. Jorge Guerra G . Server Client know-how know-how Java Applets son un buen ejemplo de este paradigma.
45. Paradigma Agente Móvil Lic. Jorge Guerra G . Host Host Cada host en esta red tiene un alto grado de flexibilidad en poseer el know-how, los recursos y los procesadores
47. Paradigma Agente Móvil Lic. Jorge Guerra G . Host Host Know-how en la forma de agentes móviles no esta unido a un único host pero esta disponible en toda la red Agente know-how
78. Arquitectura I-MODE Lic. Jorge Guerra G . Sistemas distribuidos Packet Network (PDC-P) Communication Network (PDC) iMode Server Groupware Server PSTN Info. Provider HTTP/TCP/IP Leased Line Internet Info. Provider Info. Provider PC PC HTTP/TCP/IP
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80. Arquitectura WAP Lic. Jorge Guerra G . Sistemas distribuidos Wireless Telephony Application Interface Web Server CGI Scripts, Etc... WML Decks with WML Script HTTP WTP Content WAP Gateway WML Encoder WML Script Compiler Protocol Conversion Client WML WML Script WTAI
This figure shows the architecture for the iMode network. You’ll notice there are several main functional entities here. Firstly, there are the connection endpoints. The iMode cellular phone is responsible for presenting a user interface to allow the user to easily navigate content on the iMode network. It also runs a simple network stack to encapsulate user data into network packets. The Information providers are responsible for producing and serving content. Secondly, there are the networks that provide transport. The NTT Docomo Communication Network is responsible for routing voice calls and possibly providing transit to the PSTN. The Packet network is responsible for transporting data packets between the iMode server and the iMode phones. Thirdly, the iMode server acts as a proxy to allow communication between the Packet Network and Internet resources. The iMode server can forward packets out over the internet, or over leased lines directly connected to information providers. This architecture allows for easy expansion of services. An example application is shown here. A company wishes to allow its employees to schedule meetings via their mobile phones. The company deploys a server behind the company firewall, which runs iMode compatible groupware.