Sistem distribuit (SD): sistem ale carui componente se afla pe
calculatoare
interconectate in retea, comunica si se coordoneaza prin transfer
de
mesaje.
? Caracteristici: concurenta componentelor, lipsa unui ceas
global, erori
(defecte, caderi, engl.failures) independente ale
componentelor.
? Andrew Tanenbaum: A distributed system is a collection of
independent
computers that appears to its users as a single coherent
system
The Internet system consists of a number of interconnected packet
networks supporting
communication among host computers using the Internet protocols.
These protocols include
the Internet Protocol (IP), the Internet Control Message Protocol
(ICMP), the Internet Group
Management Protocol (IGMP), and a variety transport and
application protocols that depend
upon them.
All Internet protocols use IP as the basic data transport
mechanism. IP is a datagram, or
connectionless, internetwork service and includes provision for
addressing, type-of-service
specification, fragmentation and reassembly, and security. ICMP
and IGMP are considered
integral parts of IP, although they are architecturally layered
upon IP. ICMP provides error
reporting, flow control, first-hop router redirection, and other
maintenance and control
functions. IGMP provides the mechanisms by which hosts and
routers can join and leave IP
multicast groups.