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../../protocols/email.rst:128
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the `Received:` header line is used when an email message is processed by several servers before reaching its destination. Each intermediate email server adds a `Received:` header line. These header lines are useful to debug problems in delivering email messages.
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../../protocols/ethernet.rst:169
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Standard
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../../protocols/http.rst:116
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a `method`, that indicates the type of request, a URI, and the version of the HTTP protocol used by the client
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../../protocols/http2.rst:167
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Consider now that the first object is 12500 bytes long and the second 125 bytes long. With a 1 Mbps connection, this object will use the underlying connection during 100 milliseconds. The client will thus need to wait 100 milliseconds to retrieve the second object. This is the `Head of Line` (HoL) blocking problem that affects the performance of many web services. If the short web object is a javascript code that requests other web objects, its retrieval may be critical to display the retrieved web page.
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../../protocols/ipv6.rst:111
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It is sometimes necessary to write IPv6 addresses in text format, e.g. when manually configuring addresses or for documentation purposes. The preferred format for writing IPv6 addresses is ``x:x:x:x:x:x:x:x``, where the ``x`` 's are hexadecimal digits representing the eight 16-bit parts of the address. Here are a few examples of IPv6 addresses :
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../../protocols/ethernet.rst:72
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The transport and datalink layers usually chose different strategies to place their CRCs or checksums. Transport layer protocols usually place their CRCs or checksums in the segment header. Datalink layer protocols sometimes place their CRC in the frame header, but often in a trailer at the end of the frame. This choice reflects implementation assumptions, but also influences performance :rfc:`893`. When the CRC is placed in the trailer, as in Ethernet, the datalink layer can compute it while transmitting the frame and insert it at the end of the transmission. All Ethernet interfaces use this optimization today. When the checksum is placed in the header, as in a TCP segment, it is impossible for the network interface to compute it while transmitting the segment. Some network interfaces provide hardware assistance to compute the TCP checksum, but this is more complex than if the TCP checksum were placed in the trailer [#ftso]_.
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../../protocols/routing.rst:84
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OSPF areas
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../../protocols/rpc.rst:104
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`params`: a structure that contains the values of the parameters that are passed to the method
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../../protocols/ssh.rst:211
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It is common practice among designers of security protocols to never use the same key for different purposes. For example, allowing the client and the server to use the same key to encrypt data could enable an attacker to launch a replay attack by sending to the client data that it has itself encrypted.
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../../protocols/tcp.rst:53
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the `PSH` flag is used as a notification from the sender to indicate to the receiver that it should pass all the data it has received to the receiving process. However, in practice TCP implementations do not allow TCP users to indicate when the `PSH` flag should be set.
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../../protocols/tls.rst:84
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A TLS session is divided in two phases: the handshake and the data transfer. During the handshake, the client and the server negotiate the security parameters and the keys that will be used to secure the data transfer. During the second phase, all the messages exchanged are encrypted and authenticated with the negotiated algorithms and keys.
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../../protocols/udp.rst:90
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This limitation is due to the fact that the network layer cannot transport packets that are larger than 64 KBytes. As UDP does not include any segmentation/reassembly mechanism, it cannot split a SDU before sending it. The UDP header consumes 8 bytes and the IPv6 header 60. With IPv4, the IPv4 header only consumes 20 bytes and thus the maximum UDP payload size is 65507 bytes.
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../../protocols/wifi.rst:25
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19 Mbps
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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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