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18 ../../principles/referencemodels.rst:133
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The network layer enables hosts to reach each others. However, different communication flows can take place between the same hosts. These communication flows might have different needs (some require reliable delivery, other not) and need to be distinguished. Ensuring an identification of a communication flow between two given hosts is the task of the `transport layer`. `Transport layer` entities exchange `segments`. A segment is a finite sequence of bytes that are transported inside one or more packets. A transport layer entity issues segments (or sometimes part of segments) as `Data.request` to the underlying network layer entity. 639/10000 · 639
19 ../../exercises/ex-sharing.rst:399
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Suppose now that host A uses a window of three segments and sends these three segments immediately. The segments will be queued in the router before being transmitted on the output link and delivered to their destination. The destination will reply with a short acknowledgment segment. A possible visualization of this exchange of packets is represented in the figure below. We assume for this figure that the router marks the packets to indicate congestion as soon as its buffer is non-empty when its receives a packet on its input link. In the figure, a `(c)` sign is added to each packet to indicate that it has been explicitly marked. 638/10000 · 638
19 ../../exercises/sockets.rst:171
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Depending on the socket address family, the operating system might implicitly assign an address to an unbound socket upon a call to ``write``, ``send`` or ``sendto``. While this is a useful behavior, describing it precisely is out of the scope of this section. 260/10000 · 260
19 ../../principles/naming.rst:112
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — the nameserver(s) that are responsible for any direct sub-domain of domain `dom` (i.e. `sdom1.dom` and `sdom2.dom` in the figure above, but not `z.sdom1.dom`) 158/10000 · 158
19 ../../principles/network.rst:101
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — the network layer address of the destination host 49/10000 · 49
19 ../../principles/reliability.rst:54
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — 1 Tbps 6/10000 · 6
19 ../../exercises/network.rst:141 • ../../exercises/network.rst:163 • ../../exercises/network.rst:193 • ../../exercises/network.rst:225
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Consider the network shown in the figure below. 47/10000 · 47
19 ../../glossary.rst:216
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Asynchronous Transfer Mode 26/10000 · 26
19 ../../exercises/transport.rst:145
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — A reliable connection-oriented protocol can provide a message-mode service or a byte stream service. Which of the following usages of the sequence numbers is the best suited for each of these services ? 202/10000 · 202
19 ../../principles/sharing.rst:182
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Besides the link bandwidth, the buffers on the network nodes are the second type of resource that needs to be shared inside the network. The node buffers play an important role in the operation of the network because that can be used to absorb transient traffic peaks. Consider again the example above. Assume that on average host `A` and host `B` send a group of three packets every ten seconds. Their combined transmission rate (0.6 packets per second) is, on average, lower than the network capacity (1 packet per second). However, if they both start to transmit at the same time, node `R1` will have to absorb a burst of packets. This burst of packets is a small `network congestion`. We will say that a network is congested, when the sum of the traffic demand from the hosts is larger than the network capacity :math:`\sum{demand}>capacity`. This `network congestion` problem is one of the most difficult resource sharing problem in computer networks. `Congestion` occurs in almost all networks. Minimizing the amount of congestion is a key objective for many network operators. In most cases, they will have to accept transient congestion, i.e. congestion lasting a few seconds or perhaps minutes, but will want to prevent congestion that lasts days or months. For this, they can rely on a wide range of solutions. We briefly present some of these in the paragraphs below. 1378/10000 · 1378
19 ../../principles/transport.rst:65
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Alice : `3.1415` 16/10000 · 16
19 ../../protocols/dns.rst:64
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — `CNAME` (or canonical names) are used to define aliases. For example `www.example.com` could be a `CNAME` for `pc12.example.com` that is the actual name of the server on which the web server for `www.example.com` runs. 218/10000 · 218
19 ../../principles/security.rst:261
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The security of the Caesar cipher depends on the confidentiality of the algorithm, but experience has shown that it is impossible to assume that an algorithm will remain secret, even for military applications. Instead, cryptographic techniques must be designed by assuming that the algorithm will be public and known to anyone. However, its behavior must be controlled by a small parameter, known as the key, that will only be known by the users who need to communicate secretly. This principle is attributed to Auguste Kerckhoff, a French cryptographer who first documented it : 579/10000 · 579
19 ../../exercises/dns.rst:54
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Continue until you find the server responsible for `www.root-servers.org` 73/10000 · 73
19 ../../exercises/http.rst:57
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — There are probably very few websites that only support IPv6 and not IPv4. If you find one, let us know by submitting a pull-request to change this exercise. 156/10000 · 156
19 ../../exercises/ipv6.rst:150 • ../../exercises/ipv6.rst:228
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — router ``R2`` uses address ``2001:db8:1341:12::2`` on its West interface, and address ``2001:db8:1341:24::2`` on its South interface 132/10000 · 132
19 ../../exercises/lan.rst:193
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The ``addSwitch`` method creates an Ethernet switch. It assigns a random MAC address to each switch and we can configure it with a priority that is used in the high order bits of the switch identifier. We add one IP address to each switch so that we can connect to them on mininet_. In practice, IPMininet_ configures the :manpage:`brtcl(8)` software that implements the Spanning Tree protocol on Linux. We can then create the links, configure their cost if required and launch tcpdump_ to capture the Ethernet frames that contain the messages of the Spanning Tree protocol. 574/10000 · 574
19 ../../exercises/routing-policies.rst:165
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — On recent routers, a lookup in the forwarding table for a destination address returns a set of outgoing interfaces. How would you design an algorithm that selects the outgoing interface used for each packet, knowing that to avoid reordering, all segments of a given TCP connection should follow the same path ? 310/10000 · 310
19 ../../exercises/routing-protocols.rst:257
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Router ``r2`` reacts to this updated Database description packet by requesting the link state information that it does not already know. For this, it sends a `LS Request` packet. 178/10000 · 178
19 ../../exercises/tcp-2.rst:105
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The :manpage:`accept` system call returns a new file descriptor, in this case value ``4``. At this point, packetdrill_ can write data on the socket or inject packets. 166/10000 · 166