315 lines
No EOL
22 KiB
HTML
315 lines
No EOL
22 KiB
HTML
|
|
<!DOCTYPE html>
|
|
|
|
|
|
|
|
|
|
<html lang="en">
|
|
<head>
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
|
|
|
|
<title>4.1. Networked Concurrency — Computer Systems Fundamentals</title>
|
|
|
|
<link rel="stylesheet" href="_static/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous" />
|
|
<link rel="stylesheet" href="_static/css/pygments.css" type="text/css" />
|
|
<link rel="stylesheet" href="_static/css/normalize.css" type="text/css" />
|
|
<link rel="stylesheet" href="../../../JSAV/css/JSAV.css" type="text/css" />
|
|
<link rel="stylesheet" href="../../../lib/odsaMOD-min.css" type="text/css" />
|
|
<link rel="stylesheet" href="_static/css/jquery-1.11.4-smoothness-ui.css" type="text/css" />
|
|
<link rel="stylesheet" href="../../../lib/odsaStyle-min.css" type="text/css" />
|
|
<link rel="stylesheet" href="_static/css/csf.css" type="text/css" />
|
|
|
|
<style>
|
|
.underline { text-decoration: underline; }
|
|
</style>
|
|
|
|
<script type="text/javascript">
|
|
var DOCUMENTATION_OPTIONS = {
|
|
URL_ROOT: './',
|
|
VERSION: '0.4.1',
|
|
COLLAPSE_INDEX: false,
|
|
FILE_SUFFIX: '.html',
|
|
HAS_SOURCE: true
|
|
};
|
|
</script>
|
|
|
|
<script type="text/x-mathjax-config">
|
|
MathJax.Hub.Config({
|
|
tex2jax: {
|
|
inlineMath: [['$','$'], ['\\(','\\)']],
|
|
displayMath: [ ['$$','$$'], ["\\[","\\]"] ],
|
|
processEscapes: true
|
|
},
|
|
"HTML-CSS": {
|
|
scale: "80"
|
|
}
|
|
});
|
|
</script>
|
|
<link rel="shortcut icon" href="_static/favicon.ico"/>
|
|
<link rel="index" title="Index" href="genindex.html" />
|
|
<link rel="search" title="Search" href="search.html" />
|
|
<link rel="index" title="Computer Systems Fundamentals" href="index.html" />
|
|
<link rel="next" title="2. The TCP/IP Internet Model" href="FiveLayer.html" />
|
|
<link rel="prev" title="9. Extended Example: Bash-lite: A Simple Command-line Shell" href="Extended3Bash.html" />
|
|
|
|
</head><body>
|
|
|
|
<nav class="navbar navbar-expand-md navbar-dark navbar-custom fixed-top">
|
|
|
|
<a class="navbar-brand py-0" href="index.html"><img src="_static/CSF-Logo-Square-Text.png" alt="OpenCSF Logo" height="40em" class="py-1 px-2 mb-0 align-center rounded-lg bg-white" /></a>
|
|
<!-- Show a navbar toggler on mobile -->
|
|
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#defaultNavbars" aria-controls="defaultNavbars" aria-expanded="false" aria-label="Toggle navigation">
|
|
<span class="navbar-toggler-icon"></span>
|
|
</button>
|
|
<div class="collapse navbar-collapse" id="defaultNavbars">
|
|
<ul class="navbar-nav mr-auto">
|
|
<li class="nav-item dropdown">
|
|
<a class="nav-link dropdown-toggle jmu-gold rounded" href="SocketsOverview.html#" id="navbarDropdownChapters" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">Contents</a>
|
|
<div class="dropdown-menu scrollable-menu" role="menu" aria-labelledby="navbarDropdownChapters">
|
|
<a class="dropdown-item" tabindex="-1" href="SocketsOverview.html#"><b>Chapter 1</b></a>
|
|
<a class="dropdown-item" href="IntroConcSysOverview.html"> 1.1. Introduction to Concurrent Systems</a>
|
|
<a class="dropdown-item" href="SysAndModels.html"> 1.2. Systems and Models</a>
|
|
<a class="dropdown-item" href="Themes.html"> 1.3. Themes and Guiding Principles</a>
|
|
<a class="dropdown-item" href="Architectures.html"> 1.4. System Architectures</a>
|
|
<a class="dropdown-item" href="StateModels.html"> 1.5. State Models in UML</a>
|
|
<a class="dropdown-item" href="SequenceModels.html"> 1.6. Sequence Models in UML</a>
|
|
<a class="dropdown-item" href="StateModelImplementation.html"> 1.7. Extended Example: State Model Implementation</a>
|
|
<div class="dropdown-divider"></div>
|
|
<a class="dropdown-item disabled"><b>Chapter 2</b></a>
|
|
<a class="dropdown-item" href="ProcessesOverview.html"> 2.1. Processes and OS Basics</a>
|
|
<a class="dropdown-item" href="Multiprogramming.html"> 2.2. Processes and Multiprogramming</a>
|
|
<a class="dropdown-item" href="KernelMechanics.html"> 2.3. Kernel Mechanics</a>
|
|
<a class="dropdown-item" href="Syscall.html"> 2.4. System Call Interface</a>
|
|
<a class="dropdown-item" href="ProcessCycle.html"> 2.5. Process Life Cycle</a>
|
|
<a class="dropdown-item" href="UnixFile.html"> 2.6. The UNIX File Abstraction</a>
|
|
<a class="dropdown-item" href="EventsSignals.html"> 2.7. Events and Signals</a>
|
|
<a class="dropdown-item" href="Extended2Processes.html"> 2.8. Extended Example: Listing Files with Processes</a>
|
|
<div class="dropdown-divider"></div>
|
|
<a class="dropdown-item disabled"><b>Chapter 3</b></a>
|
|
<a class="dropdown-item" href="IPCOverview.html"> 3.1. Concurrency with IPC</a>
|
|
<a class="dropdown-item" href="IPCModels.html"> 3.2. IPC Models</a>
|
|
<a class="dropdown-item" href="Pipes.html"> 3.3. Pipes and FIFOs</a>
|
|
<a class="dropdown-item" href="MMap.html"> 3.4. Shared Memory With Memory-mapped Files</a>
|
|
<a class="dropdown-item" href="POSIXvSysV.html"> 3.5. POSIX vs. System V IPC</a>
|
|
<a class="dropdown-item" href="MQueues.html"> 3.6. Message Passing With Message Queues</a>
|
|
<a class="dropdown-item" href="ShMem.html"> 3.7. Shared Memory</a>
|
|
<a class="dropdown-item" href="IPCSems.html"> 3.8. Semaphores</a>
|
|
<a class="dropdown-item" href="Extended3Bash.html"> 3.9. Extended Example: Bash-lite: A Simple Command-line Shell</a>
|
|
<div class="dropdown-divider"></div>
|
|
<a class="dropdown-item disabled"><b>Chapter 4</b></a>
|
|
<a class="dropdown-item" href="SocketsOverview.html"> 4.1. Networked Concurrency</a>
|
|
<a class="dropdown-item" href="FiveLayer.html"> 4.2. The TCP/IP Internet Model</a>
|
|
<a class="dropdown-item" href="NetApps.html"> 4.3. Network Applications and Protocols</a>
|
|
<a class="dropdown-item" href="Sockets.html"> 4.4. The Socket Interface</a>
|
|
<a class="dropdown-item" href="TCPSockets.html"> 4.5. TCP Socket Programming: HTTP</a>
|
|
<a class="dropdown-item" href="UDPSockets.html"> 4.6. UDP Socket Programming: DNS</a>
|
|
<a class="dropdown-item" href="AppBroadcast.html"> 4.7. Application-Layer Broadcasting: DHCP</a>
|
|
<a class="dropdown-item" href="Extended4CGI.html"> 4.8. Extended Example: CGI Web Server</a>
|
|
<div class="dropdown-divider"></div>
|
|
<a class="dropdown-item disabled"><b>Chapter 5</b></a>
|
|
<a class="dropdown-item" href="InternetOverview.html"> 5.1. The Internet and Connectivity</a>
|
|
<a class="dropdown-item" href="AppLayer.html"> 5.2. Application Layer: Overlay Networks</a>
|
|
<a class="dropdown-item" href="TransLayer.html"> 5.3. Transport Layer</a>
|
|
<a class="dropdown-item" href="NetSec.html"> 5.4. Network Security Fundamentals</a>
|
|
<a class="dropdown-item" href="NetLayer.html"> 5.5. Network Layer: IP</a>
|
|
<a class="dropdown-item" href="LinkLayer.html"> 5.6. Link Layer</a>
|
|
<a class="dropdown-item" href="Wireless.html"> 5.7. Wireless Connectivity: Wi-Fi, Bluetooth, and Zigbee</a>
|
|
<a class="dropdown-item" href="Extended5DNS.html"> 5.8. Extended Example: DNS client</a>
|
|
<div class="dropdown-divider"></div>
|
|
<a class="dropdown-item disabled"><b>Chapter 6</b></a>
|
|
<a class="dropdown-item" href="ThreadsOverview.html"> 6.1. Concurrency with Multithreading</a>
|
|
<a class="dropdown-item" href="ProcVThreads.html"> 6.2. Processes vs. Threads</a>
|
|
<a class="dropdown-item" href="RaceConditions.html"> 6.3. Race Conditions and Critical Sections</a>
|
|
<a class="dropdown-item" href="POSIXThreads.html"> 6.4. POSIX Thread Library</a>
|
|
<a class="dropdown-item" href="ThreadArgs.html"> 6.5. Thread Arguments and Return Values</a>
|
|
<a class="dropdown-item" href="ImplicitThreads.html"> 6.6. Implicit Threading and Language-based Threads</a>
|
|
<a class="dropdown-item" href="Extended6Input.html"> 6.7. Extended Example: Keyboard Input Listener</a>
|
|
<a class="dropdown-item" href="Extended6Primes.html"> 6.8. Extended Example: Concurrent Prime Number Search</a>
|
|
<div class="dropdown-divider"></div>
|
|
<a class="dropdown-item disabled"><b>Chapter 7</b></a>
|
|
<a class="dropdown-item" href="SynchOverview.html"> 7.1. Synchronization Primitives</a>
|
|
<a class="dropdown-item" href="CritSect.html"> 7.2. Critical Sections and Peterson's Solution</a>
|
|
<a class="dropdown-item" href="Locks.html"> 7.3. Locks</a>
|
|
<a class="dropdown-item" href="Semaphores.html"> 7.4. Semaphores</a>
|
|
<a class="dropdown-item" href="Barriers.html"> 7.5. Barriers</a>
|
|
<a class="dropdown-item" href="Condvars.html"> 7.6. Condition Variables</a>
|
|
<a class="dropdown-item" href="Deadlock.html"> 7.7. Deadlock</a>
|
|
<a class="dropdown-item" href="Extended7Events.html"> 7.8. Extended Example: Event Log File</a>
|
|
<div class="dropdown-divider"></div>
|
|
<a class="dropdown-item disabled"><b>Chapter 8</b></a>
|
|
<a class="dropdown-item" href="SynchProblemsOverview.html"> 8.1. Synchronization Patterns and Problems</a>
|
|
<a class="dropdown-item" href="SynchDesign.html"> 8.2. Basic Synchronization Design Patterns</a>
|
|
<a class="dropdown-item" href="ProdCons.html"> 8.3. Producer-Consumer Problem</a>
|
|
<a class="dropdown-item" href="ReadWrite.html"> 8.4. Readers-Writers Problem</a>
|
|
<a class="dropdown-item" href="DiningPhil.html"> 8.5. Dining Philosophers Problem and Deadlock</a>
|
|
<a class="dropdown-item" href="CigSmokers.html"> 8.6. Cigarette Smokers Problem and the Limits of Semaphores and Locks</a>
|
|
<a class="dropdown-item" href="Extended8ModExp.html"> 8.7. Extended Example: Parallel Modular Exponentiation</a>
|
|
<div class="dropdown-divider"></div>
|
|
<a class="dropdown-item disabled"><b>Chapter 9</b></a>
|
|
<a class="dropdown-item" href="ParallelDistributedOverview.html"> 9.1. Parallel and Distributed Systems</a>
|
|
<a class="dropdown-item" href="ParVConc.html"> 9.2. Parallelism vs. Concurrency</a>
|
|
<a class="dropdown-item" href="ParallelDesign.html"> 9.3. Parallel Design Patterns</a>
|
|
<a class="dropdown-item" href="Scaling.html"> 9.4. Limits of Parallelism and Scaling</a>
|
|
<a class="dropdown-item" href="DistTiming.html"> 9.5. Timing in Distributed Environments</a>
|
|
<a class="dropdown-item" href="DistDataStorage.html"> 9.6. Reliable Data Storage and Location</a>
|
|
<a class="dropdown-item" href="DistConsensus.html"> 9.7. Consensus in Distributed Systems</a>
|
|
<a class="dropdown-item" href="Extended9Blockchain.html"> 9.8. Extended Example: Blockchain Proof-of-Work</a>
|
|
<div class="dropdown-divider"></div>
|
|
<a class="dropdown-item disabled"><b>Appendix A</b></a>
|
|
<a class="dropdown-item" href="CLangOverview.html"> A.1. C Language Reintroduction</a>
|
|
<a class="dropdown-item" href="Debugging.html"> A.2. Documentation and Debugging</a>
|
|
<a class="dropdown-item" href="BasicTypes.html"> A.3. Basic Types and Pointers</a>
|
|
<a class="dropdown-item" href="Arrays.html"> A.4. Arrays, Structs, Enums, and Type Definitions</a>
|
|
<a class="dropdown-item" href="Functions.html"> A.5. Functions and Scope</a>
|
|
<a class="dropdown-item" href="Pointers.html"> A.6. Pointers and Dynamic Allocation</a>
|
|
<a class="dropdown-item" href="Strings.html"> A.7. Strings</a>
|
|
<a class="dropdown-item" href="FunctionPointers.html"> A.8. Function Pointers</a>
|
|
<a class="dropdown-item" href="Files.html"> A.9. Files</a>
|
|
</div>
|
|
</li>
|
|
|
|
|
|
|
|
</ul>
|
|
</div>
|
|
|
|
<ul class="navbar-nav flex-row ml-md-auto d-none d-md-flex">
|
|
<li class="nav-item"><a class="nav-link jmu-gold" href="https://w3.cs.jmu.edu/kirkpams/OpenCSF/Books/csf/source/SocketsOverview.rst"
|
|
target="_blank" rel="nofollow">Show Source</a></li>
|
|
|
|
</ul>
|
|
</nav>
|
|
|
|
|
|
<div class="container center">
|
|
«  <a id="prevmod" href="Extended3Bash.html">3.9. Extended Example: Bash-lite: A Simple Command-line Shell</a>
|
|
  ::  
|
|
<a class="uplink" href="index.html">Contents</a>
|
|
  ::  
|
|
<a id="nextmod" href="FiveLayer.html">4.2. The TCP/IP Internet Model</a>  »
|
|
|
|
</div>
|
|
<br />
|
|
|
|
|
|
|
|
<script type="text/javascript" src="_static/js/jquery-2.1.4.min.js"></script>
|
|
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.1/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script>
|
|
<script type="text/javascript" src="_static/js/jquery-1.11.4-ui.min.js"></script>
|
|
<script type="text/javascript" src="_static/js/forge-0.7.0.min.js"></script>
|
|
<script type="text/javascript" src="../../../JSAV/lib/jquery.transit.js"></script>
|
|
<script type="text/javascript" src="../../../JSAV/lib/raphael.js"></script>
|
|
<script type="text/javascript" src="../../../JSAV/build/JSAV-min.js"></script>
|
|
<script type="text/javascript" src="_static/js/config.js"></script>
|
|
<script type="text/javascript" src="../../../lib/odsaUtils-min.js"></script>
|
|
<script type="text/javascript" src="../../../lib/odsaMOD-min.js"></script>
|
|
<script type="text/javascript" src="_static/js/d3-4.13.0.min.js"></script>
|
|
<script type="text/javascript" src="_static/js/d3-selection-multi.v1.min.js"></script>
|
|
<script type="text/javascript" src="../../../lib/dataStructures.js"></script>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
<div class="container">
|
|
|
|
<script>ODSA.SETTINGS.DISP_MOD_COMP = true;ODSA.SETTINGS.MODULE_NAME = "SocketsOverview";ODSA.SETTINGS.MODULE_LONG_NAME = "Networked Concurrency";ODSA.SETTINGS.MODULE_CHAPTER = "Networked Concurrency"; ODSA.SETTINGS.BUILD_DATE = "2021-06-01 15:31:50"; ODSA.SETTINGS.BUILD_CMAP = false;JSAV_OPTIONS['lang']='en';JSAV_EXERCISE_OPTIONS['code']='java';</script><div class="section" id="networked-concurrency">
|
|
<h1>4.1. Networked Concurrency<a class="headerlink" href="SocketsOverview.html#networked-concurrency" title="Permalink to this headline">¶</a></h1>
|
|
<div class="figure mb-2 align-center" style="width: 100%">
|
|
<a class="reference internal image-reference" href="_images/CSF-Timeline.4.png"><img class="p-3 mb-2 align-center border border-dark rounded-lg" alt="Timeline of major CSF topics with Sockets and Networking highlighted" src="_images/CSF-Timeline.4.png" style="width: 90%;" /></a>
|
|
</div>
|
|
<blockquote class="blockquote text-center">
|
|
<p>“The web is more a social creation than a technical one. I designed
|
|
it for a social effect - to help people work together - and not as a technical toy.”
|
|
<footer class="blockquote-footer">Tim Berners-Lee</footer>
|
|
</blockquote><p>Once processes on a single machine were able to exchange data, computer scientists turned their
|
|
attention to bridging the gap between machines. The next step in the evolution of concurrency
|
|
involved adapting the file abstraction to a network interface. Joel M. Winett defined the socket in
|
|
RFC 147 (1971) as unique identifiers for transmitting data to the ARPA network, creating an
|
|
instrumental abstraction that continues to serve as the basis of networked communications programming.</p>
|
|
<div class="topic border border-dark rounded-lg bg-light px-2 mb-3">
|
|
<div class="figure align-left" style="width: 5%">
|
|
<a class="reference internal image-reference" href="_images/CSF-Images-Objectives.png"><img alt="Decorative chapter objectives image" src="_images/CSF-Images-Objectives.png" style="width: 100%;" /></a>
|
|
</div>
|
|
<p class="topic-title first pt-2 mb-1">Chapter Objectives</p><hr class="mt-1" />
|
|
<p>In this chapter, we will address the following instructional objectives:</p>
|
|
<ul class="simple">
|
|
<li>We will define the fundamental building blocks of the TCP/IP Internet model,
|
|
including its structure as a layered architecture.</li>
|
|
<li>We will describe the key components and architectural structures of network
|
|
applications.</li>
|
|
<li>We will examine how the socket API is used to implement network
|
|
applications.</li>
|
|
<li>We will implement of basic features of three protocols (HTTP, DNS, DHCP) that
|
|
demonstrate key features of TCP and UDP socket programming.</li>
|
|
</ul>
|
|
</div>
|
|
<p>IPC provides a communication infrastructure that can be used in two very different ways. Architects
|
|
of complex, interrelated applications can distribute the workload across processes to benefit from
|
|
fault isolation guarantees, while maintaining a centralized means to coordinate the work. One
|
|
example of this approach is a web browser that uses distinct processes for each tab opened; a
|
|
plug-in crash in one tab would not affect any others. On the other hand, developers and users of
|
|
simple applications may leverage IPC to chain these modules together to perform a more complex
|
|
calculation. Linking multiple command-line processes together with a pipe illustrates this approach.</p>
|
|
<p>Both of these approaches benefit from a high degree of reliability, as all of the services are
|
|
running on the same machine. For instance, if one process sends data through a message queue or pipe
|
|
to another process, that data is unlikely to be lost by the kernel. Similarly, if two processes with
|
|
similar privileges are both accessing a file on disk, it is unlikely that one of them will be able
|
|
to read the file while the other cannot. Certainly, in these scenarios, misconfigurations or
|
|
software errors make it possible for the communication to fail, but the system infrastructure itself
|
|
is unlikely to cause such failures.</p>
|
|
<p>We can extend the goals and basic principles of IPC to networked communication between processes on
|
|
different machines, but this extension does not maintain the same levels of reliability as local
|
|
communication. That is, concurrent applications that are designed to run on top of <em>networked
|
|
computer systems</em>—our focus is on the <a class="reference internal" href="Glossary.html#term-internet"><span class="xref std std-term">Internet</span></a> in particular—commonly experience
|
|
intermittent faults that cannot be attributed simply to misconfigurations or software errors. The
|
|
network infrastructure itself introduces an element of volatility that applications must take into
|
|
consideration. Fortunately, the network infrastructure provides services that can help to create
|
|
reliable communication, if the application truly requires it.</p>
|
|
<p>In this chapter, we will introduce the general structure of the networked communication
|
|
infrastructure used in the Internet. Our focus here is on the programming interface—the
|
|
<a class="reference internal" href="Glossary.html#term-socket"><span class="xref std std-term">socket</span></a> API—that software developers can use to communicate with processes running on
|
|
different machines. We will also explore details of three common <a class="reference internal" href="Glossary.html#term-protocol"><span class="xref std std-term">protocols</span></a> that
|
|
highlight key features of socket programming. In the next chapter, we will then focus on the network
|
|
as a system itself.</p>
|
|
</div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
|
|
<div class="container">
|
|
|
|
<div class="mt-4 container center">
|
|
«  <a id="prevmod1" href="Extended3Bash.html">3.9. Extended Example: Bash-lite: A Simple Command-line Shell</a>
|
|
  ::  
|
|
<a class="uplink" href="index.html">Contents</a>
|
|
  ::  
|
|
<a id="nextmod1" href="FiveLayer.html">4.2. The TCP/IP Internet Model</a>  »
|
|
</div>
|
|
|
|
|
|
</div>
|
|
|
|
<br />
|
|
|
|
<div class="row jmu-dark-purple-bg">
|
|
<div class="col-md-12">
|
|
<center>
|
|
<a id="contact_us" class="btn button-link-no-blue jmu-gold" rel="nofollow" href="mailto:webmaster@opencsf.org" role="button">Contact Us</a>
|
|
<a id="license" class="btn button-link-no-blue jmu-gold" rel="nofollow" href="https://w3.cs.jmu.edu/kirkpams/OpenCSF/lib/license.html" target="_blank">License</a>
|
|
</center>
|
|
</div>
|
|
</div>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
<script src="_static/js/popper.js-1.14.7-min.js" integrity="sha384-UO2eT0CpHqdSJQ6hJty5KVphtPhzWj9WO1clHTMGa3JDZwrnQq4sF86dIHNDz0W1" crossorigin="anonymous"></script>
|
|
<script src="_static/js/bootstrap.min.js" integrity="sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM" crossorigin="anonymous"></script>
|
|
</body>
|
|
</html> |