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../../protocols/ipv6.rst:121
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``0:0:0:0:0:0:0:1`` is represented as ``::1``
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../../protocols/ethernet.rst:99
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The first property is a consequence of the utilization of CSMA/CD. The second property is a consequence of the physical organization of the Ethernet network as a shared bus. These two properties are important and all revisions to the Ethernet technology have preserved them.
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../../protocols/routing.rst:101
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On the other hand, consider the prefixes `2001:db8:aaaa:0000::/64` and `2001:db8:aaaa:0001::/64` that are inside `area 1`. Router `RA` is the only area border router that is attached to this area. This router can create two different network summary advertisements :
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../../protocols/rpc.rst:118
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`error`: if the method called does not exist or its execution causes an error, the `result` element will be replaced by an `error` element which contains the following members :
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../../protocols/ssh.rst:246
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Authenticating messages with HMAC
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../../protocols/tcp.rst:111
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A TCP connection is established by using a three-way handshake. The connection establishment phase uses the `sequence number`, the `acknowledgment number` and the `SYN` flag. When a TCP connection is established, the two communicating hosts negotiate the initial sequence number to be used in both directions of the connection. For this, each TCP entity maintains a 32 bits counter, which is supposed to be incremented by one at least every 4 microseconds and after each connection establishment [#ftcpclock]_. When a client host wants to open a TCP connection with a server host, it creates a TCP segment with :
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../../protocols/tls.rst:130
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In a nutshell, the client starts the TLS handshake by proposing a random nonce. The server replies with its random nonce and a certificate that binds its name to a public key. The client generates a MasterSecret that will be used later to derive the session keys and encrypts it with the public key of the server. It also generates a `Finished` message that contains a MAC of all the messages exchanged to allow the server to detect any modification of the messages sent by the client. The server also sends its own `Finished` message. At that point, the client and the server sent encrypted records thanks to the keys derived from the MasterSecret.
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../../protocols/wifi.rst:35
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The architecture of WiFi networks is slightly different from the Local Area Networks that we have discussed until now. There are, in practice, two main types of WiFi networks : `independent` or `adhoc` networks and `infrastructure` networks [#fBSS]_. An `independent` or `adhoc` network is composed of a set of devices that communicate with each other. These devices play the same role and the `adhoc` network is usually not connected to the global Internet. `Adhoc` networks are used when for example a few laptops need to exchange information or to connect a computer with a WiFi printer.
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../../bibliography.rst:107
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Kleinrock, L., Tobagi, F., `Packet Switching in Radio Channels: Part I--Carrier Sense Multiple-Access Modes and their Throughput-Delay Characteristics <https://dx.doi.org/10.1109/TCOM.1975.1092768>`_, IEEE Transactions on Communications, Vol. COM-23, No. 12, pp. 1400-1416, December 1975.
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../../glossary.rst:171
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eBGP
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../../exercises/ex-sharing.rst:630
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Hosts `A` and `B` use the simple congestion control scheme described in the book and router `R1` uses the DECBIT mechanism to mark packets as soon as its buffers contain one packet. Hosts `A` and `B` need to send five segments and start exactly at the same time. How long does each hosts needs to wait to receive the acknowledgment for its fifth segment ?
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../../principles/network.rst:130
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The simplest `control plane` for a network is to manually compute the forwarding tables of all routers inside the network. This simple control plane is sufficient when the network is (very) small, usually up to a few routers.
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../../principles/transport.rst:71
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`line feed` (`LF`) : `0001010b`
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../../principles/sharing.rst:155
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When a network node forwards small packets, its performance is usually limited by the number of lookup operations that it can perform every second. This lookup performance is measured in packets per second. The performance may depend on the length of the forwarded packets. The key performance factor is the number of minimal size packets that are forwarded by the node every second. This rate can lead to a capacity in bits per second which is much lower than the sum of the bandwidth of the node's links.
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../../principles/security.rst:375
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A public key cryptographic scheme is a combination of two functions :
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../../exercises/dns.rst:113
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On a Linux machine, the *Description* section of the `dig` man page tells you where `dig` finds the list of nameservers to query.
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../../exercises/ipv6.rst:330
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The students have configured the following forwarding tables on these six routers.
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../../exercises/routing-protocols.rst:380
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To explore the configuration of BGP, let us consider a network that contains three ASes: ``AS1``, ``AS2`` and ``AS3``. To simplify the tests, we identify one host inside each of these ASes.
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../../exercises/tcp-2.rst:261
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Let us first use packetdrill_ to explore the evolution of the TCP retransmission timeout. The value of this timeout is set based on the measured round-trip-time and its variance. When the retransmission timer expires, TCP doubles the retransmission timer. This exponential backoff mechanism is important to ensure that TCP slowdowns during very severe congestion periods. We use the ``tcpi_rto`` variable from ``TCP_INFO`` to track the evolution of the retransmission timer. This script is available from :download:`/exercises/packetdrill_scripts/rto.pkt`.
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../../protocols/bgp.rst:116
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A BGP peering session between two directly connected routers
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