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../../exercises/sockets.rst:105
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`DATA.indication(message)` is issued by the transport service to deliver a message to the application. In the socket API, this corresponds to the return of the ``recv`` method that is called by the application.
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../../exercises/transport.rst:57
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What are the acknowledgments sent by `Host B`. How does `Host A` react and how does it terminate the connection ?
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../../principles/naming.rst:23
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However, the limitations of a flat naming scheme became clear before the end of the ARPANet and :rfc:`819` proposed a hierarchical naming scheme. While :rfc:`819` discussed the possibility of organizing the names as a directed graph, the Internet opted for a tree structure capable of containing all names. In this tree, the top-level domains are those that are directly attached to the root. The first top-level domain was `.arpa` [#fdnstimeline]_. This top-level name was initially added as a suffix to the names of the hosts attached to the ARPANet and listed in the `hosts.txt` file. In 1984, the `.gov`, `.edu`, `.com`, `.mil` and `.org` generic top-level domain names were added. :rfc:`1032` proposed the utilization of the two letter :term:`ISO-3166` country codes as top-level domain names. Since :term:`ISO-3166` defines a two letter code for each country recognized by the United Nations, this allowed all countries to automatically have a top-level domain. These domains include `.be` for Belgium, `.fr` for France, `.us` for the USA, `.ie` for Ireland or `.tv` for Tuvalu, a group of small islands in the Pacific or `.tm` for Turkmenistan. The set of top-level domain-names is managed by the Internet Corporation for Assigned Names and Numbers (:term:`ICANN`). :term:`ICANN` adds generic top-level domains that are not related to a country and the `.cat` top-level domain has been registered for the Catalan language. There are ongoing discussions within :term:`ICANN` to increase the number of top-level domains.
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../../principles/network.rst:29
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The second type of datalink layer is the one used in Local Area Networks (LAN). Conceptually, a LAN is a set of communicating devices such that any two devices can directly exchange frames through the datalink layer. Both hosts and routers can be connected to a LAN. Some LANs only connect a few devices, but there are LANs that can connect hundreds or even thousands of devices. In this chapter, we focus on the utilization of point-to-point datalink layers. We describe later the organization and the operation of Local Area Networks and their impact on the network layer.
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../../principles/referencemodels.rst:34
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Starting from the bottom, the first layer is the Physical layer. Two communicating devices are linked through a physical medium. This physical medium is used to transfer an electrical or optical signal between two directly connected devices.
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../../principles/reliability.rst:39
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The physical layer
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../../principles/transport.rst:27
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An `application-level protocol` is similar to a structured conversation between humans. Assume that Alice wants to know the current time but does not have a watch. If Bob passes close by, the following conversation could take place :
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../../bibliography.rst:28
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Beech, W., Nielsen, D., Taylor, J., `AX.25 Link Access Protocol for Amateur Packet Radio <http://www.tapr.org/pdf/AX25.2.2.pdf>`_, version 2.2, Revision: July 1998
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../../glossary.rst:119
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Application Programming Interface
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../../index.rst:149
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Appendices
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../../exercises/ex-sharing.rst:150
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In ALOHA, the hosts rely on acknowledgments to detect whether their frame has been received correctly by the destination. Consider a network running at 100 Mbps where the host exchange 1000 bits frames and acknowledgments of 100 bits. Draw the frames sent by hosts A and B in the figure below. Assume that a square corresponds to 10 microseconds and that the cable has a length of 2 kilometers.
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../../exercises/network.rst:94
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In this network, assume that all the link weights are set to 1. What is the paths followed by a packet sent by the router located in `Los Angeles` to reach :
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../../exercises/reliability.rst:26
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a Cyclic Redundancy Check (`CRC`)
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../../exercises/sockets.rst:107
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The `DATA` primitives are exchanged through a service access point. In the socket API, the equivalent to the service access point is the `socket`. A `socket` is a data structure which is maintained by the networking stack and is used by the application every time it needs to send or receive data through the networking stack.
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../../exercises/transport.rst:60
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Consider a reliable connection-oriented transport protocol that provides the bytestream service. In this transport protocol, the sequence number that is placed inside each DATA segment reflects the position of the bytes in the bytestream. Considering the connection shown below, provide the DATA segments that are sent by `Host A` in response to the `DATA.request`, assuming that one segment is sent for each `DATA.request`.
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../../principles/naming.rst:25
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Each top-level domain is managed by an organization that decides how sub-domain names can be registered. Most top-level domain names use a first-come first served system, and allow anyone to register domain names, but there are some exceptions. For example, `.gov` is reserved for the US government, `.int` is reserved for international organizations and names in the `.ca` are mainly `reserved <http://en.wikipedia.org/wiki/.ca>`_ for companies or users that are present in Canada.
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../../principles/sharing.rst:36
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A third organization of a computer network is a star topology. In such networks, hosts have a single physical interface and there is one physical link between each host and the center of the star. The node at the center of the star can be either a piece of equipment that amplifies an electrical signal, or an active device, such as a piece of equipment that understands the format of the messages exchanged through the network. Of course, the failure of the central node implies the failure of the network. However, if one physical link fails (e.g. because the cable has been cut), then only one node is disconnected from the network. In practice, star-shaped networks are easier to operate and maintain than bus-shaped networks. Many network administrators also appreciate the fact that they can control the network from a central point. Administered from a Web interface, or through a console-like connection, the center of the star is a useful point of control (enabling or disabling devices) and an excellent observation point (usage statistics).
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../../principles/transport.rst:29
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Alice : `Hello`
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../../bibliography.rst:35
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Bux, W., `Token-ring local-area networks and their performance <http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=18625>`_, Proceedings of the IEEE, Vol 77, No 2, p. 238-259, Feb. 1989
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../../glossary.rst:268
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ARP
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