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../../principles/sharing.rst:402
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[KT1975]_ analyzes in detail the performance of several CSMA variants. Under some assumptions about the transmission channel and the traffic, the analysis compares ALOHA, slotted ALOHA, persistent and non-persistent CSMA. Under these assumptions, ALOHA achieves a channel utilization of only 18.4% of the channel capacity. Slotted ALOHA is able to use 36.6% of this capacity. Persistent CSMA improves the utilization by reaching 52.9% of the capacity while non-persistent CSMA achieves 81.5% of the channel capacity.
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../../principles/security.rst:951
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Alice chooses a secret integer : :math:`a=8` and sends :math:`A= g^{a} \mod p= 5^{8} \mod 23=16` to Bob
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../../exercises/ipv6.rst:808
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Another interesting mininet_ command is ``pingall`` it allows to check that any host can reach any other host inside the network. It executes a ping from any host to any other host inside the network topology.
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../../exercises/routing-protocols.rst:1272
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Let us now consider another example, also implemented using an IPMininet_ script. The network contains eight ASes with one host per AS. This small Internet is shown below and the script is available from :download:`/exercises/ipmininet_scripts/ebgp-bug-3.py`.
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../../protocols/bgp.rst:346
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Sometimes, the `local-pref` attribute is used to prefer a `cheap` link compared to a more expensive one. For example, in the network below, `AS1` could wish to send and receive packets mainly via its interdomain link with `AS4`.
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../../protocols/email.rst:242 • ../../protocols/email.rst:244
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5
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../../protocols/ethernet.rst:357
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20000
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../../protocols/ipv6.rst:337
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`Next Header` : this 8-bit field indicates the type [#fianaprotocol]_ of header that follows the IPv6 header. It can be a transport layer header (e.g. `6` for TCP or `17` for UDP) or an IPv6 option.
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../../protocols/ethernet.rst:331
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The switches exchange `BPDUs` to build the spanning tree. Intuitively, the spanning tree is built by first selecting the switch with the smallest `identifier` as the root of the tree. The branches of the spanning tree are then composed of the shortest paths that allow all of the switches that compose the network to be reached. The `BPDUs` exchanged by the switches contain the following information :
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../../protocols/tcp.rst:263
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the current state of the TCP FSM
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../../protocols/tls.rst:482
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On the web, TLS clients use certificates to authenticate servers but the clients are not authenticated. However, there are environments such as enterprise networks where servers may need to authenticate clients as well. A popular deployment is to authenticate remote clients who wish to access the enterprise network through a Virtual Private Network service. Some of these services run above TLS (or more precisely a variant of TLS named DTLS that runs above UDP [MoR2004]_ but is outside the scope of this chapter). In such services, each client is authenticated thanks to a public key and a certificate that is trusted by the servers. To establish a TLS session, such a client needs to prove that it owns the public key associated with the certificate. This is done by the server thanks to the CertificateRequest message. The TLS handshake becomes the following one:
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../../glossary.rst:146
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Intermediate System- Intermediate System. A link-state intradomain routing that was initially defined for the ISO CLNP protocol but was extended to support IP v4 and IP v6. IS-IS is often used in ISP networks. It is defined in [ISO10589]_
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../../principles/network.rst:365
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For example, consider the `label forwarding table` of a network node below.
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../../principles/reliability.rst:306
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In this section, we develop a reliable datalink protocol running above the physical layer service. To design this protocol, we first assume that the physical layer provides a perfect service. We will then develop solutions to recover from the transmission errors.
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../../principles/sharing.rst:407
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Carrier Sense Multiple Access with Collision Detection
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../../principles/security.rst:953
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Bob chooses a secret integer : :math:`b=13` and sends :math:`B= g^{b} \mod p=5^{13} \mod 23=21` to Alice
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../../exercises/ipv6.rst:819
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When debugging a network, it can be interesting to capture packets using tcpdump_ on specific links to check that they follow the expect. If you use tcpdump_ without any filter, you will capture the packets generated by xterm. To capture packets, you need to specify precise filters that will match the packets of interest. For traceroute6, you need to match the IPv6 packets that contain UDP segments and some ICMPv6 packets. The script below provides a simple filter that you can reuse. It takes one argument: the name of the interface on which tcpdump_ needs to run.
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../../exercises/routing-protocols.rst:1312
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The network does not provide a full connectivity. The hosts attached to ``AS5`` cannot ping the hosts attached to ``AS8``.
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../../protocols/bgp.rst:352
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How to prefer a cheap link over an more expensive one ?
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../../protocols/email.rst:242
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F
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