2. cnp3-ebook
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21 ../../exercises/network.rst:185
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The network operator uses would like to have the following paths in this network : 82/10000 · 82
21 ../../exercises/reliability.rst:41
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Same question when using selective repeat instead of go-back-n. Note that the answer is not necessarily the same. 113/10000 · 113
21 ../../glossary.rst:155
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The Border Gateway Protocol is the interdomain routing protocol used in the global Internet. 92/10000 · 92
21 ../../exercises/transport.rst:148
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — DATA segments contain a sequence number that is incremented for each DATA segment transmitted 93/10000 · 93
21 ../../principles/sharing.rst:188
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Congestion collapse on the Internet 35/10000 · 35
21 ../../protocols/dns.rst:68
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The DNS is mainly used to find the address that corresponds to a given name. However, it is sometimes useful to obtain the name that corresponds to an IP address. This done by using the `PTR` (`pointer`) `RR`. The `RData` part of a `PTR` `RR` contains the name while the `Name` part of the `RR` contains the IP address encoded in the `in-addr.arpa` domain. IPv4 addresses are encoded in the `in-addr.arpa` by reversing the four digits that compose the dotted decimal representation of the address. For example, consider IPv4 address `192.0.2.11`. The hostname associated to this address can be found by requesting the `PTR` `RR` that corresponds to `11.2.0.192.in-addr.arpa`. A similar solution is used to support IPv6 addresses :rfc:`3596`, but slightly more complex given the length of the IPv6 addresses. For example, consider IPv6 address `2001:1890:123a::1:1e`. To obtain the name that corresponds to this address, we need first to convert it in a reverse dotted decimal notation : `e.1.0.0.1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.a.3.2.1.0.9.8.1.1.0.0.2`. In this notation, each character between dots corresponds to one nibble, i.e. four bits. The low-order byte (`e`) appears first and the high order (`2`) last. To obtain the name that corresponds to this address, one needs to append the `ip6.arpa` domain name and query for `e.1.0.0.1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.a.3.2.1.0.9.8.1.1.0.0.2.ip6.arpa`. In practice, tools and libraries do the conversion automatically and the user does not need to worry about it. 1514/10000 · 1514
21 ../../principles/security.rst:279
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — This principle is important because it remains the basic assumption of all cryptographers. Any system that relies on the secrecy of its algorithm to be considered secure is doomed to fail and be broken one day. 210/10000 · 210
21 ../../exercises/dns.rst:57
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Perform the same analysis for a popular website such as `www.google.com`. What is the lifetime associated to the corresponding IPv6 address ? If you perform the same request several times, do you always receive the same answer ? Can you explain why a lifetime is associated to the DNS replies ? 294/10000 · 294
21 ../../exercises/ipv6.rst:154
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Routers ``R2`` and ``R3`` are buggy in this network. Besides the routes for their local interfaces (not shown in the figure), they only have a default route which is shown in the figure below. 192/10000 · 192
21 ../../exercises/lan.rst:211
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — By using :manpage:`brtcl(8)`, we can easily observe the state of the Spanning Tree protocol on the different switches. Let us start with ``s3``, i.e. the root of the Spanning Tree. 180/10000 · 180
21 ../../exercises/routing-policies.rst:191
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Can you explain why at the eighth, ninth and tenth hopes several IPv6 addresses are reported in the ``traceroute6`` output ? 124/10000 · 124
21 ../../exercises/routing-protocols.rst:265
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — OSPFv3 also includes `LS Acknowledge` packets that acknowledge the correct reception of link state information. 111/10000 · 111
21 ../../exercises/tcp-2.rst:115
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — packetdrill_ can also inject data that will be read by the stack as shown by the lines below. 93/10000 · 93
21 ../../exercises/trace.rst:111
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — the `wireshark wiki <https://wiki.wireshark.org/>` page on `Display filters <https://wiki.wireshark.org/DisplayFilters>`_ 121/10000 · 121
21 ../../protocols/bgp.rst:72
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Finally, the last type of peering relationship is the `sibling`. Such a relationship is used when two domains exchange all their routes in both directions. In practice, such a relationship is only used between domains that belong to the same company. 250/10000 · 250
21 ../../protocols/congestion.rst:110
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The second difficulty is how to allow the receiver to inform the sender of the reception of network packets marked with the `CE` bit. In reliable transport protocols like TCP and SCTP, the acknowledgments can be used to provide this feedback. For TCP, two options were possible : change some bits in the TCP segment header or define a new TCP option to carry this information. The designers of ECN opted for reusing spare bits in the TCP header. More precisely, two TCP flags have been added in the TCP header to support ECN. The `ECN-Echo` (ECE) is set in the acknowledgments when the `CE` was set in packets received on the forward path. 639/10000 · 639
21 ../../protocols/dnssec.rst:196
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The next step is to contact `ns.org`, the `NS` responsible for the `.org` TLD to retrieve the `NS` record for the `example.org` domain. This record is accompanied by a `RRSIG` record that authenticates it. This `RRSIG` record is signed with the key of the `.org` domain. Alice's resolver can retrieve this public key as the `DNSKEY` record for the `.org`, but how can it trust this key since it is distributed by using the DNS and could have been modified by attackers ? DNSSEC solves this problem by using the `DS` record that is stored in the parent zone (in this case, the root zone). This record contains a hash of a public key that is signed with a `RRSIG` signature. Since Alice's resolver's trusts the root key, it can validate the signature of the `DS` record for the `.org` domain. It can then retrieve the `DNSKEY` record for this domain from the DNS and compare the hash of this key with the `DS` record. If they match, the public key of the `.org` domain can be trusted. The same technique is used to obtain and validate the key of the `example.org` domain. Once this key is trusted, Alice's resolver can request the `AAAA` record for `www.example.org` and validate its signature. 1192/10000 · 1192
21 ../../protocols/email.rst:109
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — A simple email message containing the `From:`, `To:`, `Subject:` and `Date:` header lines and two lines of body is shown below. 127/10000 · 127
21 ../../protocols/ethernet.rst:118
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The introduction of the twisted pairs led to two major changes to Ethernet. The first change concerns the physical topology of the network. 10Base2 and 10Base5 networks are shared buses, the coaxial cable typically passes through each room that contains a connected computer. A 10BaseT network is a star-shaped network. All the devices connected to the network are attached to a twisted pair cable that ends in the telecom closet. From a maintenance perspective, this is a major improvement. The cable is a weak point in 10Base2 and 10Base5 networks. Any physical damage on the cable broke the entire network and when such a failure occurred, the network administrator had to manually check the entire cable to detect where it was damaged. With 10BaseT, when one twisted pair is damaged, only the device connected to this twisted pair is affected and this does not affect the other devices. The second major change introduced by 10BaseT was that is was impossible to build a 10BaseT network by simply connecting all the twisted pairs together. All the twisted pairs must be connected to a relay that operates in the physical layer. This relay is called an `Ethernet hub`. A `hub` is thus a physical layer relay that receives an electrical signal on one of its interfaces, regenerates the signal and transmits it over all its other interfaces. Some `hubs` are also able to convert the electrical signal from one physical layer to another (e.g. 10BaseT to 10Base2 conversion). 1474/10000 · 1474
21 ../../protocols/http.rst:100
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — More complex HTML elements can also include optional attributes in the start tag :: 83/10000 · 83