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../../principles/network.rst:104
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The figure illustrates some possible forwarding tables in this network. By inspecting the forwarding tables of the different routers, one can find the path followed by packets sent from a source to a particular destination. In the example above, host `A` sends its packet to router `R1`. `R1` consults its forwarding table and forwards the packet towards `R2`. Based on its own table, `R2` decides to forward the packet to `R5` that can deliver it to its destination. Thus, the path from `A` to `J` is `A -> R1 -> R2 -> R5 -> J`.
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../../principles/referencemodels.rst:116
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physical layer entities exchange bits
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../../principles/reliability.rst:66
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every millisecond, record the voltage applied on the electrical wire. If the voltage is set to ``+5V``, record the reception of bit `1`. Otherwise, record the reception of bit `0`
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../../principles/sharing.rst:139
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Congestion collapse on the Internet
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../../principles/transport.rst:60
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Application-layer protocols exchange two types of messages. Some protocols such as those used to support electronic mail exchange messages expressed as strings or lines of characters. As the transport layer allows hosts to exchange bytes, they need to agree on a common representation of the characters. The first and simplest method to encode characters is to use the :term:`ASCII` table. :rfc:`20` provides the ASCII table that is used by many protocols on the Internet. For example, the table defines the following binary representations :
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../../bibliography.rst:93
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ISO, `Intermediate System to Intermediate System intra-domain routeing information exchange protocol for use in conjunction with the protocol for providing the connectionless-mode network service (ISO 8473) <http://standards.iso.org/ittf/PubliclyAvailableStandards/c030932_ISO_IEC_10589_2002(E).zip>`_ , 2002
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../../glossary.rst:131
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Classless Inter Domain Routing is the current address allocation architecture for IP version 4. It was defined in :rfc:`1518` and :rfc:`4632`.
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../../exercises/ex-sharing.rst:564
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When analyzing the reaction of a network using round-robin schedulers, it is sometimes useful to consider that the packets sent by each source are equivalent to a fluid and that each scheduler acts as a tap. Using this analogy, consider the network below. In this network, all the links are 100 Mbps and host `B` is sending packets at 100 Mbps. If A sends at 1, 5, 10, 20, 30, 40, 50, 60, 80 and 100 Mbps, what is the throughput that destination `D` will receive from `A`. Use this data to plot a graph that shows the portion of the traffic sent by host `A` which is received by host `D`.
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../../exercises/sockets.rst:261
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Until now, we learned how to use sockets that were already created. When writing a whole program, you will have to create you own sockets and choose the concrete technology that it will use to communicate with others. In this section, we will create new sockets and allow a program to communicate with processes located on another computer using a network. The most recent standardized technology used to communicate through a network is the :term:`IPv6` network protocol. In the IPv6 protocol, hosts are identified using *IPv6 addresses*. Modern operating systems allow IPv6 network communications between programs to be done using the socket API, just as we did in the previous sections.
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../../principles/naming.rst:128
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if there are many concurrent clients, the load of the server will increase without any possibility of adding another server without changing the server addresses used by the clients
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../../principles/referencemodels.rst:117
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datalink layer entities exchange *frames*
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../../principles/reliability.rst:70
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This transmission scheme has been used in some early networks. We use it as a basis to understand how hosts communicate. From a Computer Science viewpoint, dealing with voltages is unusual. Computer scientists frequently rely on models that enable them to reason about the issues that they face without having to consider all implementation details. The physical transmission scheme described above can be represented by using a `time-sequence diagram`.
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../../principles/sharing.rst:141
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Congestion collapse is unfortunately not only an academic experience. Van Jacobson reports in [Jacobson1988]_ one of these events that affected him while he was working at the Lawrence Berkeley Laboratory (LBL). LBL was two network nodes away from the University of California in Berkeley. At that time, the link between the two sites had a bandwidth of 32 Kbps, but some hosts were already attached to 10 Mbps LANs. "In October 1986, the data throughput from LBL to UC Berkeley ... dropped from 32 Kbps to 40 bps. We were fascinated by this sudden factor-of-thousand drop in bandwidth and embarked on an investigation of why things had gotten so bad." This work lead to the development of various congestion control techniques that have allowed the Internet to continue to grow without experiencing widespread congestion collapse events.
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../../principles/transport.rst:62
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`A` : `1000011b`
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../../bibliography.rst:94
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Jacobson, V., `Congestion avoidance and control <http://doi.acm.org/10.1145/52324.52356>`_. In Symposium Proceedings on Communications Architectures and Protocols (Stanford, California, United States, August 16 - 18, 1988). V. Cerf, Ed. SIGCOMM '88. ACM, New York, NY, 314-329.
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../../glossary.rst:283
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dial-up line
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../../exercises/ex-sharing.rst:582
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Compute the max-min fair bandwidth allocation in the network below.
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../../exercises/network.rst:250
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The network below uses port forwarding tables. It has been running for several hours and all hosts have exchanged packets. What is the content of the port forwarding tables ?
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../../exercises/sockets.rst:264
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A program can use the ``socket`` system call to create a new socket.
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../../principles/network.rst:108
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In a network, a path can be defined as the list of all intermediate routers for a given source destination pair. For a given source/destination pair, the path can be derived by first consulting the forwarding table of the router attached to the source to determine the next router on the path towards the chosen destination. Then, the forwarding table of this router is queried for the same destination... The queries continue until the destination is reached. In a network that has valid forwarding tables, all the paths between all source/destination pairs contain a finite number of intermediate routers. However, if forwarding tables have not been correctly computed, two types of invalid paths can occur.
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