Exit Zen
12
../../protocols/transport-service.rst:25
English
IPv4 addresses are usually represented by using a dotted decimal representation where each decimal number corresponds to one byte of the address, e.g. `203.0.113.56`. IPv6 addresses are usually represented as a set of hexadecimal numbers separated by semicolons, e.g. `2001:db8:3080:2:217:f2ff:fed6:65c0`. Today, most Internet hosts have one IPv4 address. A small fraction of them also have an IPv6 address. In the future, we can expect that more and more hosts will have IPv6 addresses and that some of them will not have an IPv4 address anymore. A host that only has an IPv4 address cannot communicate with a host having only an IPv6 address. The figure below illustrates two applications that are using the datagram service provided by UDP on hosts that are using IPv4 addresses.
0/7820 · 782
12
../../protocols/udp.rst:54
English
a 16 bits destination port
0/260 · 26
12
../../protocols/wifi.rst:22 • ../../protocols/wifi.rst:24 • ../../protocols/wifi.rst:25
English
2.4 GHz
0/100 · 7
13
../../bibliography.rst:40
English
Chiu, D., Jain, R., `Analysis of the Increase and Decrease Algorithms for Congestion Avoidance in Computer Networks <https://dx.doi.org/10.1016/0169-7552(89)90019-6>`_, Computer Networks and ISDN Systems Vol 17, pp 1-14, 1989
0/2250 · 225
13
../../glossary.rst:50
English
The Advanced Research Project Agency (ARPA) Network is a network that was built by network scientists in USA with funding from the ARPA of the US Ministry of Defense. ARPANET is considered as the grandfather of today's Internet.
0/2280 · 228
13
../../exercises/ex-sharing.rst:260
English
CSMA/CD does not use acknowledgments but instead assumes that each host can detect collisions by listening while transmitting. Consider a 2 kilometers long cable running at 10 Mbps. Show in the figure below the utilization of the communication channel and the collisions that would occur. For this exercise, do not attempt to retransmit the frames that have collided.
0/3670 · 367
13
../../principles/sharing.rst:53
English
A fifth physical organization of a network is the tree. Such networks are typically used when a large number of customers must be connected in a very cost-effective manner. Cable TV networks are often organized as trees.
0/2200 · 220
13
../../principles/security.rst:179
English
As Mallory receives all the packets sent by both Bob and Alice, he can modify them at will. For example, he could modify the commands sent by Alice to the server managed by Bob and change the responses sent by the server. This type of attack is very powerful and sometimes difficult to counter without relying on advanced cryptographic techniques.
0/3470 · 347
13
../../exercises/dns.rst:43
English
What are the nameservers that are responsible for the `info` top-level domain ? Is it possible to use IPv6 to query them ?
0/1220 · 122
13
../../exercises/http.rst:35
English
curl_ supports a huge number of options and parameters that are described in its `man page <https://curl.haxx.se/docs/manpage.html>`_ Some of them allow you to force the utilization of a specific version of HTTP. These include `--http0.9`, `--http1.0`, `--http1.1` and `--http2`. Using the latter, verify whether your favorite website supports HTTP/2.0.
0/3530 · 353
13
../../exercises/ipv6.rst:42
English
router ``R3`` uses address ``2001:db8:1341:34::3`` on its East interface, address ``2001:db8:1341:23::3`` on its North-East interface and address ``2001:db8:1341:13::3`` on its North interface
0/1920 · 192
13
../../exercises/lan.rst:85
English
Consider the network depicted in Fig. 5. Both of the hosts `H0` and `H1` have two interfaces: one connected to the switch `S0` and the other one to the switch `S1`. Will the link between `S0` and `S1` ever be used? If so, under which assumptions? Provide a comprehensive answer.
0/2780 · 278
13
../../exercises/routing-policies.rst:143
English
Consider that the AS stub (`AS456`) shown in the figure below decides to advertise two ``/48`` prefixes instead of its allocated ``/47`` prefix.
0/1440 · 144
13
../../exercises/routing-protocols.rst:186
English
In its output, we see that ``r1`` is attached to two different routers. Finally, the ``show ipv6 ospf6 database`` returns the full OSPFv3 database with all the link state information that was distributed by OSPFv3.
0/2140 · 214
13
../../exercises/tcp-2.rst:65
English
For this first example, we program packetdrill_ to inject the segments that a client would send. The first step is thus to prepare a :manpage:`socket` that can be used to accept this connection. This socket can be created by using the four system calls below.
0/2590 · 259
13
../../exercises/trace.rst:82
English
wireshark_ is more recent than tcpdump_. It evolved from the ethereal packet trace analysis software. It can be used as a text tool like tcpdump_. For a TCP connection, wireshark_ can provide almost the same output as tcpdump_. The main advantage of wireshark_ is that it also includes a graphical user interface that allows performing various types of analysis on a packet trace.
0/3800 · 380
13
../../protocols/bgp.rst:53
English
A simple Internet with peering relationships
0/440 · 44
13
../../protocols/congestion.rst:46
English
Most TCP implementations update the congestion window when they receive an acknowledgment. If we assume that the receiver acknowledges each received segment and the sender only sends MSS sized segments, the TCP congestion control scheme can be implemented using the simplified pseudo-code [#fwrap]_ below. This pseudocode includes the optimization proposed in :rfc:`3042` that allows a sender to send new unsent data upon reception of the first or second duplicate acknowledgment. The reception of each of these acknowledgment indicates that one segment has left the network and thus additional data can be sent without causing more congestion. Note that the congestion window is *not* increased upon reception of these first duplicate acknowledgments.
0/7520 · 752
13
../../protocols/dnssec.rst:158
English
DNSSEC defines four new types of DNS records that are used together to authenticate the information distributed by the DNS.
0/1230 · 123
13
../../protocols/email.rst:63
English
Email messages are entirely composed of lines of ASCII characters. Each line can contain up to 998 characters and is terminated by the `CR` and `LF` control characters :rfc:`5322`. The lines that compose the `header` appear before the message `body`. An empty line, containing only the `CR` and `LF` characters, marks the end of the `header`. This is illustrated in the figure below.
0/3830 · 383