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../../protocols/congestion.rst:205
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:math:`Throughput=\frac{area \times MSS}{time} = \frac{ \frac{3 \times W^2}{8}}{\frac{W}{2} \times rtt}` or, after having eliminated `W`, :math:`Throughput=\sqrt{\frac{3}{2}} \times \frac{MSS}{rtt \times \sqrt{p}}`
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../../protocols/email.rst:212
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`text`. The message part contains information in textual format. There are several subtypes : `text/plain` for regular ASCII text, `text/html` defined in :rfc:`2854` for documents in :term:`HTML` format or the `text/enriched` format defined in :rfc:`1896`. The `Content-Type:` header line may contain a second parameter that specifies the character set used to encode the text. `charset=us-ascii` is the standard ASCII character table. Other frequent character sets include `charset=UTF8` or `charset=iso-8859-1`. The `list of standard character sets <http://www.iana.org/assignments/character-sets>`_ is maintained by :term:`IANA`.
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../../protocols/ethernet.rst:177
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1000Base-CX
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../../protocols/http.rst:160
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the `Content-Encoding:` header indicates how the :term:`MIME document` has been encoded. For example, this header would be set to `x-gzip` for a document compressed using the gzip_ software.
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../../protocols/http2.rst:267
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See https://en.wikipedia.org/wiki/HTTP_pipelining for additional information.
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../../protocols/ipv6.rst:153
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An IPv6 unicast address is composed of three parts :
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../../protocols/ethernet.rst:164
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The evolution of Ethernet did not stop. In 1998, the IEEE published a first standard to provide Gigabit Ethernet over optical fibers. Several other types of physical layers were added afterwards. The `10 Gigabit Ethernet <http://en.wikipedia.org/wiki/10_gigabit_Ethernet>`_ standard appeared in 2002. Work is ongoing to develop `standards <http://www.ieee802.org/3/ba/public/index.html>`_ for 40 Gigabit and 100 Gigabit Ethernet and some are thinking about `Terabit Ethernet <http://www.networkworld.com/news/2009/042009-terabit-ethernet.html>`_. The table below lists the main Ethernet standards. A more detailed list may be found at http://en.wikipedia.org/wiki/Ethernet_physical_layer.
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../../protocols/routing.rst:133
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Remote routers, when looking at the topology distributed by OSPF, consider that there is a full-mesh of links between all the LAN routers. Such a full-mesh implies a lot of redundancy in case of failure, while in practice the entire LAN may completely fail. In case of a failure of the entire LAN, all routers need to detect the failures and flood link state packets before the LAN is completely removed from the OSPF topology by remote routers.
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../../protocols/rpc.rst:146
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ONC-RPC uses a more complex method to allow a caller to reach the callee. On a host, server processes can run on different ports and given the limited number of port values (:math:`2^{16}` per host on the Internet), it is impossible to reserve one port number for each method. The solution used in ONC-RPC :rfc:`1831` is to use a special method which is called the `portmapper` :rfc:`1833`. The `portmapper` is a kind of directory that runs on a server that hosts methods. The `portmapper` runs on a standard port (`111` for ONC-RPC :rfc:`1833`). A server process that implements a method registers its method on the local `portmapper`. When a caller needs to call a method on a remote server, it first contacts the `portmapper` to obtain the port number of the server process which implements the method. The response from the portmapper allows it to directly contact the server process which implements the method.
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../../protocols/ssh.rst:302
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For example, :rfc:`4255` describes a DNS record that can be used to associate an ``ssh`` fingerprint to a DNS name.
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../../protocols/tcp.rst:124
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This segment is often called a `SYN+ACK` segment. The acknowledgment confirms to the client that the server has correctly received the `SYN` segment. The `sequence number` of the `SYN+ACK` segment is used by the server host to verify that the `client` has received the segment. Upon reception of the `SYN+ACK` segment, the client host replies with a segment containing :
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../../protocols/tls.rst:173
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The ``Server Name Indication (SNI)``
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../../protocols/wifi.rst:102
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The first part of the 802.11 header is the 16 bit `Frame Control` field. This field contains flags that indicate the type of frame (data frame, RTS/CTS, acknowledgment, management frames, etc), whether the frame is sent to or from a fixed LAN, etc [IEEE802.11]_. The `Duration` is a 16 bit field that is used to reserve the transmission channel. In data frames, the `Duration` field is usually set to the time required to transmit one acknowledgment frame after a SIFS delay. Note that the `Duration` field must be set to zero in multicast and broadcast frames. As these frames are not acknowledged, there is no need to reserve the transmission channel after their transmission. The `Sequence control` field contains a 12 bits sequence number that is incremented for each data frame and a 4 bits fragment number.
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../../bibliography.rst:127
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McQuillan, J.M., Richer, I., Rosen, E., `The New Routing Algorithm for the ARPANET <https://dx.doi.org/10.1109/TCOM.1980.1094721>`_ Communications, IEEE Transactions on , vol.28, no.5, pp.711,719, May 1980
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../../glossary.rst:327
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The most widely used LAN technology.
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../../exercises/ex-sharing.rst:648
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the host stops to listen and waits for a random time before sensing again the communication channel to check whether it is free.
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../../exercises/network.rst:360
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Routes on C
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../../exercises/sockets.rst:328
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Besides character strings, some applications also need to exchange 16 bits and 32 bits fields such as integers. A naive solution would have been to send the 16- or 32-bits field as it is encoded in the host's memory. Unfortunately, there are different methods to store 16- or 32-bits fields in memory. Some CPUs store the most significant byte of a 16-bits field in the first address of the field while others store the least significant byte at this location. When networked applications running on different CPUs exchange 16 bits fields, there are two possibilities to transfer them over the transport service :
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../../principles/referencemodels.rst:148
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Compared to the five layers reference model explained above, the :term:`OSI` reference model defined in [X200]_ is divided in seven layers. The four lower layers are similar to the four lower layers described above. The OSI reference model refined the application layer by dividing it in three layers :
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../../principles/reliability.rst:184
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Computer networks use a similar approach. Each layer provides a service that is built above the underlying layer and is closer to the needs of the applications. The datalink layer builds upon the service provided by the physical layer. We will see that it also contains several functions.
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