networking fundamentals,

Computer Communication Networks
A computer communication network system consists of hardware, software, and humanware. The hardware and software allow the humanware—
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the users—to create, exchange, and use information. The hardware consists
of a collection of nodes that include the end systems, commonly called hosts,
and intermediate switching elements that include hubs, bridges, routers and
gateways. We will collectively call all of these network or computing elements,
or sometimes without loss of generality, just network elements. The software,
all application programs and network protocols, synchronize and coordinate
the sharing and exchange of data among the network elements and the sharing
of expensive resources in the network. Network elements, network software,
and users, all work together so that individual users get to exchange messages
and share resources on other systems that are not readily available locally. The
network elements may be of diverse hardware technologies and the software
may be different, but the whole combo must work together in unison. This
concept that allows multiple, diverse underlying hardware technologies and
different software regimes to interconnect heterogeneous networks and bring
them to communicate is called internetworking technology. Internetworking
technology makes Gibson’s vision a reality; it makes possible the movement
and exchange of data and the sharing of resources among the network elements.
This is achieved through the low- level mechanisms provided by the network
elements and the high- level communication facilities provided by the software
running on the communicating elements. Let us see how this infrastructure
works by looking at the hardware and software components and how they
produce a working computer communication network. We will start with the
hardware components, consisting of network types and network topology.
Later, we will discuss the software components consisting of the transmission
control system.