Exit Zen
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../../glossary.rst:15
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anycast
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../../index.rst:37
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Part 1: Principles
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../../exercises/ex-sharing.rst:66
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In a shared medium, a collision may happen if two hosts transmit at almost the same time as shown in the example below.
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../../exercises/network.rst:67
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Routing protocols used in data networks only use positive link weights. What would happen with a distance vector routing protocol in the network below that contains a negative link weight ?
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../../exercises/reliability.rst:22
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A version of the Alternating Bit Protocol supporting variable length frames uses a header that contains the following fields :
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../../exercises/sockets.rst:102
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A detailed discussion of the socket API is outside the scope of this section and the references cited above provide a detailed discussion of all the details of the socket API. As a starting point, it is interesting to compare the socket API with the service primitives that we have discussed in the previous chapter. Let us first consider the connectionless service that consists of the following two primitives :
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../../exercises/transport.rst:38
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Continue the connection so that `Host B` sends `Hello` as data and `Host A` replies by sending `Pleased to meet you`. After having received the response, `Host B` closes the connection gracefully and `Host A` does the same. Discuss on the state that needs to be maintained inside each host.
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../../principles/naming.rst:19
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The first solution that allowed applications to use names was the :term:`hosts.txt` file. This file is similar to the symbol table found in compiled code. It contains the mapping between the name of each Internet host and its associated address [#fhosts]_. It was maintained by SRI International that coordinated the Network Information Center (NIC). When a new host was connected to the network, the system administrator had to register its name and address at the NIC. The NIC updated the :term:`hosts.txt` file on its server. All Internet hosts regularly retrieved the updated :term:`hosts.txt` file from the SRI_ server. This file was stored at a well-known location on each Internet host (see :rfc:`952`) and networked applications could use it to find the address corresponding to a name.
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../../protocols/dns.rst:26
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The DNS header
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../../bibliography.rst:20
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Abramson, N., `THE ALOHA SYSTEM: another alternative for computer communications <http://doi.acm.org/10.1145/1478462.1478502>`_. In Proceedings of the November 17-19, 1970, Fall Joint Computer Conference (Houston, Texas, November 17 - 19, 1970). AFIPS '70 (Fall). ACM, New York, NY, 281-285.
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../../glossary.rst:17
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a transmission mode where an information is sent from one source to `one` receiver that belongs to a specified group
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../../index.rst:54
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Part 2: Protocols
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../../exercises/ex-sharing.rst:92
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Consider the following scenario for the ALOHA medium access control algorithm. Three hosts are attached to a one-kilometer long cable and transmit 1000 bits frames at 1 Mbps. Each arrow represents a request to transmit a frame on the corresponding host. Each square represents 250 microseconds in the figure. Represent all the transmitted frames and list the frames that collide.
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../../exercises/network.rst:86
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When a network specialist designs a network, one of the problems that he needs to solve is to set the metrics the links in his network. In the USA, the Abilene network interconnects most of the research labs and universities. The figure below shows the topology of this network in 2009.
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../../exercises/reliability.rst:24
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a `number` (0 or 1)
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../../exercises/sockets.rst:104
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`DATA.request(destination,message)` is used to send a message to a specified destination. In this socket API, this corresponds to the ``send`` method.
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../../exercises/transport.rst:40
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A transport connection that provides a message-mode service has been active for some time and all data has been exchanged and acknowledged in both directions. As in the exercise above, the sequence number is incremented after the transmission of each segment. At this time, `Host A` sends two DATA segments as shown in the figure below.
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../../principles/naming.rst:21
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A :term:`hosts.txt` file can be used when there are up to a few hundred hosts on the network. However, it is clearly not suitable for a network containing thousands or millions of hosts. A key issue in a large network is to define a suitable naming scheme. The ARPANet initially used a flat naming space, i.e. each host was assigned a unique name. To limit collisions between names, these names usually contained the name of the institution and a suffix to identify the host inside the institution (a kind of poor man's hierarchical naming scheme). On the ARPANet few institutions had several hosts connected to the network.
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../../principles/network.rst:26
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There are two main types of datalink layers. The simplest datalink layer is when there are only two communicating systems that are directly connected through the physical layer. Such a datalink layer is used when there is a point-to-point link between the two communicating systems. These two systems can be hosts or routers. PPP (Point-to-Point Protocol), defined in :rfc:`1661`, is an example of such a point-to-point datalink layer. Datalink layer entities exchange `frames`. A datalink :term:`frame` sent by a datalink layer entity on the left is transmitted through the physical layer, so that it can reach the datalink layer entity on the right. Point-to-point datalink layers can either provide an unreliable service (frames can be corrupted or lost) or a reliable service (in this case, the datalink layer includes retransmission mechanisms).
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../../principles/referencemodels.rst:32 • ../../principles/referencemodels.rst:49
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The Physical layer
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