GCC 12n Guía De La Red
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This is treated as a “print job,” so connections must wait until the printer is idle. Once
connected, other print jobs must wait until the telnet connection is closed.
connected, other print jobs must wait until the telnet connection is closed.
The telnet server is intended for administration and debugging, not for printing. Telnet
clients are widely available.
clients are widely available.
Appendix TCP - A: TCP/IP overview
TCP/IP is a mature and widely used set of network protocols designed by network re-
searchers at US universities; the research was funded by the federal government. TCP/IP is
intended primarily to connect significant numbers of cooperating, general-purpose com-
puters across both short and long distances.
searchers at US universities; the research was funded by the federal government. TCP/IP is
intended primarily to connect significant numbers of cooperating, general-purpose com-
puters across both short and long distances.
TCP/IP is closely associated with the UNIX operating system—largely because the Univer-
sity of California at Berkeley has included solid implementations in their UNIX since
4.2BSD in 1984, and Berkeley gives away their source code. Many other implementations
of UNIX and TCP/IP are derived from Berkeley’s. However, TCP/IP software is available
on a wide variety of computers and operating systems, including Apple Macintoshes, PC-
compatibles, most UNIX workstations, Digital Equipment Corporation VAXes running
VMS, and some mainframes.
sity of California at Berkeley has included solid implementations in their UNIX since
4.2BSD in 1984, and Berkeley gives away their source code. Many other implementations
of UNIX and TCP/IP are derived from Berkeley’s. However, TCP/IP software is available
on a wide variety of computers and operating systems, including Apple Macintoshes, PC-
compatibles, most UNIX workstations, Digital Equipment Corporation VAXes running
VMS, and some mainframes.
TCP/IP actually includes a number of cooperating protocols. The core protocols are TCP,
UDP, IP, ICMP, ARP (on Ethernet and similar nets), and one or more routing protocols
(most commonly RIP.) The protocols are, like most sets of network protocols, arranged
hierarchically, where each layer supplies services to the layer above it and uses the layer
below it as a tool.
UDP, IP, ICMP, ARP (on Ethernet and similar nets), and one or more routing protocols
(most commonly RIP.) The protocols are, like most sets of network protocols, arranged
hierarchically, where each layer supplies services to the layer above it and uses the layer
below it as a tool.
The TCP/IP protocol hierarchy, when running on Ethernet, is structured as follows:
Applications (ftp, e-mail, telnet, lpr, etc.)
TCP
UDP
ARP
IP
ICMP
Ethernet
IP (Internet Protocol) supplies unreliable datagrams (messages) among hosts running
TCP/IP across multiple networks connected by routers. (Routers are special-purpose
computers connected to two or more networks, that forward IP datagrams from one
network to another.) IP is the core of the TCP/IP protocols. An IP host is identified by a
TCP/IP across multiple networks connected by routers. (Routers are special-purpose
computers connected to two or more networks, that forward IP datagrams from one
network to another.) IP is the core of the TCP/IP protocols. An IP host is identified by a