Exit Zen
14
../../protocols/rpc.rst:36
English
For basic data types, :rfc:`1832` simply maps their representation into a sequence of bytes. For example a 32 bits integer is transmitted as follows (with the most significant byte first, which corresponds to big-endian encoding).
0/2300 · 230
14
../../protocols/ssh.rst:121
English
This negotiation of the cryptographic algorithms allows the implementations to evolve when new algorithms are proposed. If a client is upgraded, it can announce a new algorithm as its preferred one even if the server is not yet upgraded.
0/2370 · 237
14
../../protocols/tcp.rst:39
English
the address of the client
0/250 · 25
14
../../protocols/tls.rst:44
English
993
0/100 · 3
14
../../protocols/transport-service.rst:49
English
It is sometimes necessary to write IPv6 addresses in text format, e.g. when manually configuring addresses or for documentation purposes. The preferred format for writing IPv6 addresses is `x:x:x:x:x:x:x:x`, where the `x` 's are hexadecimal digits representing the eight 16-bit parts of the address. Here are a few examples of IPv6 addresses :
0/3430 · 343
14
../../protocols/udp.rst:56
English
a 16 bits checksum
0/180 · 18
14
../../protocols/wifi.rst:22
English
2 Mbps
0/100 · 6
15
../../bibliography.rst:51
English
Cohen, D., `On Holy Wars and a Plea for Peace`, IEN 137, April 1980, http://www.ietf.org/rfc/ien/ien137.txt
0/1070 · 107
15
../../glossary.rst:14
English
The American Standard Code for Information Interchange (ASCII) is a character-encoding scheme that defines a binary representation for characters. The ASCII table contains both printable characters and control characters. ASCII characters were encoded in 7 bits and only contained the characters required to write text in English. Other character sets such as Unicode have been developed later to support all written languages.
0/4270 · 427
15
../../exercises/ex-sharing.rst:316
English
An important part of the CSMA/CD algorithm is the exponential backoff. To illustrate the operation of this algorithm, let us consider a cable that has a length of one kilometer. The bandwidth of the network is set to 10 Mbps. Assume that when a collision occurs, host A always selects the highest possible random delay according to the exponential backoff algorithm while host B always selects the shortest one. In this network, the slot time is equal to the time required to transmit 100 bits. We further assume that a host can detect collision immediately (i.e. as soon as the other frame arrives).
0/6000 · 600
15
../../principles/transport.rst:41
English
Such a conversation succeeds if both Alice and Bob speak the same language. If Alice meets Tchang who only speaks Chinese, she won't be able to ask him the current time. A conversation between humans can be more complex. For example, assume that Bob is a security guard whose duty is to only allow trusted secret agents to enter a meeting room. If all agents know a secret password, the conversation between Bob and Trudy could be as follows :
0/4430 · 443
15
../../principles/sharing.rst:62
English
Sharing bandwidth
0/170 · 17
15
../../principles/security.rst:198
English
In practice, there is a possibility of denial of service attacks as soon as there is a limited resource somewhere in the network. This resource can be the bandwidth of a link, but it could also be the computational power of a server, its memory or even the size of tables used by a given protocol implementation. Defending against real DoS attacks can be difficult, especially if the attacker controls a large number of sources that are used to launch the attacks. In terms of bandwidth, DoS attacks composed of a few Gbps to a few tens of Gbps of traffic are frequent on the Internet. In 2015, `github.com <http://www.github.com>`_ suffered from a distributed DoS that reached a top bandwidth of 400 Gbps according to some `reports <http://www.techworld.com/news/security/worlds-largest-ddos-attack-reached-400gbps-says-arbor-networks-3595715/>`_.
0/8480 · 848
15
../../exercises/dns.rst:48
English
When run without any parameter, `dig` queries one of the root DNS servers and retrieves the list of the names of all root DNS servers. For technical reasons, there are only 13 different root DNS servers. This information is also available as a text file from http://www.internic.net/zones/named.root. What are the IPv6 addresses of all these servers?
0/3500 · 350
15
../../exercises/ipv6.rst:45
English
The forwarding paths used in a network depend on the forwarding tables installed in the network nodes. Sometimes, these forwarding tables must be configured manually.
0/1660 · 166
15
../../exercises/lan.rst:93
English
Most commercial Ethernet switches are able to run the Spanning tree protocol independently on each VLAN. What are the benefits of using per-VLAN spanning trees ?
0/1610 · 161
15
../../exercises/routing-policies.rst:153
English
How is the reachability of these addresses affected when link `R1`-`R3` fails ?
0/790 · 79
15
../../exercises/routing-protocols.rst:241
English
The first packet that this router received his a Hello packet that was sent by router ``r2``. There are several interesting points to note about this packet. First, its source address is the link-local address (``fe80::68bc:b4ff:fe19:42b7``) of router ``r2`` on this interface. The destination address of the packet is reserved IPv6 multicast address for OSPFv3, i.e. ``ff02::5``. The Hop Limit of the packet is set to 1 and OSFPv3 uses a next header of type 89.
0/4620 · 462
15
../../exercises/tcp-2.rst:86
English
Each line of a packetdrill_ script starts with a `timing` parameter that indicates at what time the event specified on this line should happen. packetdrill_ supports absolute and relative timings. An absolute timing is simply a number that indicates the delay in seconds between the start of the script and the event. A relative timing is indicated by using ``+`` followed by a number. This number is then the delay in seconds between the previous event and the current line. Additional information may be found in [CCB+2013]_.
0/5280 · 528
15
../../exercises/trace.rst:94
English
The wireshark_ window is divided in three parts. The top part of the window is a summary of the first packets from the trace. By clicking on one of the lines, you can show the detailed content of this packet in the middle part of the window. The middle of the window allows you to inspect all the fields of the captured packet. The bottom part of the window is the hexadecimal representation of the packet, with the field selected in the middle window being highlighted.
0/4700 · 470