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diff --git a/share/doc/smm/18.net/2.t b/share/doc/smm/18.net/2.t new file mode 100644 index 00000000000..f5048897cba --- /dev/null +++ b/share/doc/smm/18.net/2.t @@ -0,0 +1,85 @@ +.\" Copyright (c) 1983, 1986, 1993 +.\" The Regents of the University of California. All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. All advertising materials mentioning features or use of this software +.\" must display the following acknowledgement: +.\" This product includes software developed by the University of +.\" California, Berkeley and its contributors. +.\" 4. Neither the name of the University nor the names of its contributors +.\" may be used to endorse or promote products derived from this software +.\" without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" @(#)2.t 8.1 (Berkeley) 6/8/93 +.\" +.nr H2 1 +.\".ds RH Overview +.br +.ne 2i +.NH +\s+2Overview\s0 +.PP +If we consider +the International Standards Organization's (ISO) +Open System Interconnection (OSI) model of +network communication [ISO81] [Zimmermann80], +the networking facilities +described here correspond to a portion of the +session layer (layer 3) and all of the transport and +network layers (layers 2 and 1, respectively). +.PP +The network layer provides possibly imperfect +data transport services with minimal addressing +structure. +Addressing at this level is normally host to host, +with implicit or explicit routing optionally supported +by the communicating agents. +.PP +At the transport +layer the notions of reliable transfer, data sequencing, +flow control, and service addressing are normally +included. Reliability is usually managed by +explicit acknowledgement of data delivered. Failure +to acknowledge a transfer results in retransmission of +the data. Sequencing may be handled by tagging +each message handed to the network layer by a +\fIsequence number\fP and maintaining +state at the endpoints of communication to utilize +received sequence numbers in reordering data which +arrives out of order. +.PP +The session layer facilities may provide forms of +addressing which are mapped into formats required +by the transport layer, service authentication +and client authentication, etc. Various systems +also provide services such as data encryption and +address and protocol translation. +.PP +The following sections begin by describing some of the common +data structures and utility routines, then examine +the internal layering. The contents of each layer +and its interface are considered. Certain of the +interfaces are protocol implementation specific. For +these cases examples have been drawn from the Internet [Cerf78] +protocol family. Later sections cover routing issues, +the design of the raw socket interface and other +miscellaneous topics. |