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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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../../principles/security.rst:401
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Another interesting property of public key cryptography is its ability to compute `signatures` that can be used to authenticate a message. This capability comes from the utilization of two different keys that are linked together. If Alice wants to sign a message `M`, she can compute :math:`SM=E_p(A_{priv},M)`. Anyone who receives this signed messaged can extract its content as :math:`D_p(A_{pub},SM)=D_p(A_{pub},E_p(A_{priv},M))=M`. Everyone can use :math:`A_{pub}` to check that the message was signed by using Alice's private key (:math:`A_{priv}`). Since this key is only known by Alice, the ability to decrypt `SM` is a proof that the message was signed by Alice herself.
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../../exercises/ipv6.rst:433
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What do you think about the proposed configuration?
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../../exercises/routing-protocols.rst:510
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The script ends by launching the full topology. The entire script is available from :download:`/exercises/ipmininet_scripts/ebgp-simple.py`.
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../../exercises/tcp-2.rst:546
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Another interesting scenario is when the loss happens early in the data transfer. This is shown in the script below where the second segment is lost. We observe that by triggering transmissions of unacknowledged data, the :rfc:`3042` rule speeds up the recovery since a fast retransmit happens. This script is available from :download:`/exercises/packetdrill_scripts/slow-start-frr2.pkt`.
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../../protocols/bgp.rst:129
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As explained earlier, BGP relies on incremental updates. This implies that when a BGP session starts, each router first sends BGP `UPDATE` messages to advertise to the other peer all the exportable routes that it knows. Once all these routes have been advertised, the BGP router only sends BGP `UPDATE` messages about a prefix if the route is new, one of its attributes has changed or the route became unreachable and must be withdrawn. The BGP `UPDATE` message allows BGP routers to efficiently exchange such information while minimizing the number of bytes exchanged. Each `UPDATE` message contains :
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../../protocols/congestion.rst:209
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More detailed models and the analysis of simulations have shown that a first order model of the TCP throughput when losses occur was :math:`Throughput \approx \frac{k \times MSS}{rtt \times \sqrt{p}}`. This is an important result which shows that :
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../../protocols/email.rst:213
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`image`. The message part contains a binary representation of an image. The subtype indicates the format of the image such as `gif <http://en.wikipedia.org/wiki/Graphics_Interchange_Format>`_, `jpg <http://en.wikipedia.org/wiki/Jpeg>`_ or `png <http://en.wikipedia.org/wiki/Portable_Network_Graphics>`_.
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