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76 ../../principles/reliability.rst:261
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — `STX`: `0000010` b 18/10000 · 18
76 ../../principles/sharing.rst:484
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Many improvements to ALOHANet have been proposed since the publication of [Abramson1970]_, and this technique, or some of its variants, are still found in wireless networks today. The slotted technique proposed in [Roberts1975]_ is important because it shows that a simple modification can significantly improve channel utilization. Instead of allowing all terminals to transmit at any time, [Roberts1975]_ proposed to divide time into slots and allow terminals to transmit only at the beginning of each slot. Each slot corresponds to the time required to transmit one fixed size frame. In practice, these slots can be imposed by a single clock that is received by all terminals. In ALOHANet, it could have been located on the central mainframe. The analysis in [Roberts1975]_ reveals that this simple modification improves the channel utilization by a factor of two. 867/10000 · 867
76 ../../principles/transport.rst:364
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Unfortunately, the `message-mode` transfer is not widely used on the Internet. On the Internet, the most popular connection-oriented service transfers SDUs in `stream-mode`. With the `stream-mode`, the service provider supplies a byte stream that links the two communicating users. The sending user sends bytes by using `Data.request` primitives that contain sequences of bytes as SDUs. The service provider delivers SDUs containing consecutive bytes to the receiving user by using `Data.indication` primitives. The service provider ensures that all the bytes sent at one end of the stream are delivered correctly in the same order at the other endpoint. However, the service provider does not attempt to preserve the boundaries of the SDUs. There is no relation enforced by the service provider between the number of `Data.request` and the number of `Data.indication` primitives. The `stream-mode` is illustrated in the figure below. In practice, a consequence of the utilization of the `stream-mode` is that if the users want to exchange structured SDUs, they will need to provide the mechanisms that allow the receiving user to separate successive SDUs in the byte stream that it receives. Application layer protocols often use specific delimiters such as the end of line character to delineate SDUs in a bytestream. 1319/10000 · 1319
76 ../../principles/security.rst:891
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — agree on a way to encrypt the messages that they will exchange 62/10000 · 62
76 ../../exercises/ipv6.rst:696
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — To help students to start using IPMininet, `Mathieu Jadin <https://inl.info.ucl.ac.be/mjadin.html>`_ has created a Vagrant box that launches a Ubuntu virtual machine with all the required software. See https://ipmininet.readthedocs.io/en/latest/install.html for additional information. 285/10000 · 285
76 ../../exercises/routing-protocols.rst:1066
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Draw the network and try to predict how it will react to a shutdown of any of the customer-provider links ? 107/10000 · 107
76 ../../protocols/bgp.rst:298
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The first solution is the most frequent. Advertising routes learned from an intradomain routing protocol is not recommended, this is because if the route flaps [#fflap]_, this would cause a large number of BGP messages being exchanged in the global Internet. 258/10000 · 258
76 ../../protocols/email.rst:238
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — U 1/10000 · 1
76 ../../protocols/ethernet.rst:336
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — the `identifier` of the switch that sent the `BPDU` (`T`) 57/10000 · 57
76 ../../protocols/http.rst:391
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The third and widely adopted solution are HTTP cookies. HTTP cookies were initially developed as a private extension by Netscape_. They are now part of the standard :rfc:`6265`. In a nutshell, a cookie is a short string that is chosen by a server to represent a given client. Two HTTP headers are used : `Cookie:` and `Set-Cookie:`. When a server receives an HTTP request from a new client (i.e. an HTTP request that does not contain the `Cookie:` header), it generates a cookie for the client and includes it in the `Set-Cookie:` header of the returned HTTP response. The `Set-Cookie:` header contains several additional parameters including the domain names for which the cookie is valid. The client stores all received cookies on disk and every time it sends an HTTP request, it verifies whether it already knows a cookie for this domain. If so, it attaches the `Cookie:` header to the HTTP request. This is illustrated in the figure below with HTTP 1.1, but cookies also work with HTTP 1.0. 994/10000 · 994
76 ../../protocols/ipv6.rst:291
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Finally, :rfc:`4291` defines the structure of the IPv6 multicast addresses [#fmultiiana]_. This structure is depicted in the figure below. 138/10000 · 138
76 ../../protocols/ethernet.rst:289
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — From a security perspective, Ethernet hubs have the same drawbacks as the older coaxial cable. A host attached to a hub will be able to capture all the frames exchanged between any pair of hosts attached to the same hub. Ethernet switches are much better from this perspective thanks to the selective forwarding, a host will usually only receive the frames destined to itself as well as the multicast, broadcast and unknown frames. However, this does not imply that switches are completely secure. There are, unfortunately, attacks against Ethernet switches. From a security perspective, the `MAC address table` is one of the fragile elements of an Ethernet switch. This table has a fixed size. Some low-end switches can store a few tens or a few hundreds of addresses while higher-end switches can store tens of thousands of addresses or more. From a security point of view, a limited resource can be the target of Denial of Service attacks. Unfortunately, such attacks are also possible on Ethernet switches. A malicious host could overflow the `MAC address table` of the switch by generating thousands of frames with random source addresses. Once the `MAC address table` is full, the switch needs to broadcast all the frames that it receives. At this point, an attacker will receive unicast frames that are not destined to its address. The ARP attack discussed in the previous chapter could also occur with Ethernet switches [Vyncke2007]_. Recent switches implement several types of defenses against these attacks, but they need to be carefully configured by the network administrator. See [Vyncke2007]_ for a detailed discussion on security issues with Ethernet switches. 1675/10000 · 1675
76 ../../protocols/tcp.rst:245
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The original TCP data transfer mechanisms were defined in :rfc:`793`. Based on the experience of using TCP on the growing global Internet, this part of the TCP specification has been updated and improved several times, always while preserving the backward compatibility with older TCP implementations. In this section, we review the main data transfer mechanisms used by TCP. 375/10000 · 375
76 ../../protocols/tls.rst:403
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — simplify the design by removing unused or unsafe protocol features 66/10000 · 66
77 ../../bibliography.rst:100
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Jain, R., `Congestion control in computer networks : Issues and trends <https://dx.doi.org/10.1109/65.56532>`_, IEEE Network Magazine, May 1990, pp. 24-30 154/10000 · 154
77 ../../glossary.rst:292
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — For DNS servers and resolvers, an inverse query is a query for the domain name that corresponds to a given IP address. 118/10000 · 118
77 ../../principles/network.rst:431
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The first solution to the fragmentation problem presented above suggests the utilization of control packets to inform the source about the reception of a too long packet. This is only one of the functions that are performed by the control protocol in the network layer. Other functions include : 295/10000 · 295
77 ../../principles/reliability.rst:262
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — `ETX`: `0000011` b 18/10000 · 18
77 ../../principles/sharing.rst:490
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Carrier Sense Multiple Access 29/10000 · 29
77 ../../principles/security.rst:893
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Let us first explore how this could be realized by using public-key cryptography. We assume that Alice and Bob have both a public-private key pair and the corresponding certificates signed by a trusted third party : Ted. 220/10000 · 220