Exit Zen
6
../../protocols/transport-service.rst:15
English
The connectionless transport service allows networked application to exchange messages. Several networked applications may be running at the same time on a single host. Each of these applications must be able to exchange SDUs with remote applications. To enable these exchanges of SDUs, each networked application running on a host is identified by the following information :
0/3760 · 376
6
../../protocols/udp.rst:17
English
Compared to the connectionless network layer service, the main advantage of the UDP service is that it allows several applications running on a host to exchange SDUs with several other applications running on remote hosts. Let us consider two hosts, e.g. a client and a server. The network layer service allows the client to send information to the server, but if an application running on the client wants to contact a particular application running on the server, then an additional addressing mechanism is required other than the IP address that identifies a host, in order to differentiate the application running on a host. This additional addressing is provided by `port numbers`. When a server using UDP is enabled on a host, this server registers a `port number`. This `port number` will be used by the clients to contact the server process via UDP.
0/8570 · 857
6
../../protocols/wifi.rst:19
English
Standard
0/100 · 8
7
../../bibliography.rst:20
English
Abramson, N., `THE ALOHA SYSTEM: another alternative for computer communications <http://doi.acm.org/10.1145/1478462.1478502>`_. In Proceedings of the November 17-19, 1970, Fall Joint Computer Conference (Houston, Texas, November 17 - 19, 1970). AFIPS '70 (Fall). ACM, New York, NY, 281-285.
0/2910 · 291
7
../../glossary.rst:17
English
a transmission mode where an information is sent from one source to `one` receiver that belongs to a specified group
0/1160 · 116
7
../../exercises/ex-sharing.rst:92
English
Consider the following scenario for the ALOHA medium access control algorithm. Three hosts are attached to a one-kilometer long cable and transmit 1000 bits frames at 1 Mbps. Each arrow represents a request to transmit a frame on the corresponding host. Each square represents 250 microseconds in the figure. Represent all the transmitted frames and list the frames that collide.
0/3790 · 379
7
../../principles/transport.rst:25
English
Networked applications do not exchange random messages. In order to ensure that the server is able to understand the queries sent by a client, and also that the client is able to understand the responses sent by the server, they must both agree on a set of syntactical and semantic rules. These rules define the format of the messages exchanged as well as their ordering. This set of rules is called an application-level `protocol`.
0/4320 · 432
7
../../principles/sharing.rst:28
English
The second possible physical organization, which is also used inside computers to connect different extension cards, is the bus. In a bus network, all hosts are attached to a shared medium, usually a cable through a single interface. When one host sends an electrical signal on the bus, the signal is received by all hosts attached to the bus. A drawback of bus-based networks is that if the bus is physically cut, then the network is split into two isolated networks. For this reason, bus-based networks are sometimes considered to be difficult to operate and maintain, especially when the cable is long and there are many places where it can break. Such a bus-based topology was used in early Ethernet networks.
0/7140 · 714
7
../../principles/security.rst:64
English
When analyzing security issues in computer networks, it is useful to reason about the capabilities of the attacker who wants to exploit some breach in the security of the network. There are different types of attackers. Some have generic capabilities, others are specific to a given technology or network protocol. In this section, we discuss some important threats that a network architect must take into account.
0/4140 · 414
7
../../exercises/dns.rst:33
English
where
0/100 · 5
7
../../exercises/email.rst:16
English
Use your preferred email tool to send an email message to yourself containing a single line of text. Most email tools have the ability to show the `source` of the message, use this function to look at the message that you sent and the message that you received. Can you find an explanation for all the lines that have been added to your single line email ?
0/3560 · 356
7
../../exercises/http.rst:23
English
Can you explain the different headers found in the response ?
0/610 · 61
7
../../exercises/ipv6.rst:33 • ../../exercises/ipv6.rst:142
English
Consider the network shown in the figure below. In this network, the following addresses are used.
0/980 · 98
7
../../exercises/lan.rst:56
English
Many enterprise networks are organized with a set of backbone devices interconnected by using a full mesh of links as shown in Fig.2. In this network, what are the benefits and drawbacks of using Ethernet switches and IP routers running OSPF ?
0/2430 · 243
7
../../exercises/routing-policies.rst:60
English
from `AS4` to `AS1`
0/190 · 19
7
../../exercises/routing-protocols.rst:94
English
Finally, we can start the IPMininet_ topology and launch the daemons. The entire script is available from :download:`/exercises/ipmininet_scripts/ospf6.py`.
0/1560 · 156
7
../../exercises/tcp-2.rst:22
English
packetdrill_ executes a system call and verifies its return value
0/650 · 65
7
../../exercises/trace.rst:35
English
A first solution to analyze this trace is to use tcpdump_ on the command line. The `-n` disables the reverse DNS lookups that tcpdump_ does by default for all IP addresses. The `-r` argument is the name of the file contained the captured packets. The trace starts with the DNS request. This request was sent over IPv4 which is the default on this host. tcpdump_ indicates the query and the response returned by the local DNS resolver.
0/4340 · 434
7
../../protocols/bgp.rst:27
English
Interconnection of two domains via a private peering link
0/570 · 57
7
../../protocols/congestion.rst:24
English
`mild congestion`. TCP considers that the network is lightly congested if it receives three duplicate acknowledgments and performs a fast retransmit. If the fast retransmit is successful, this implies that only one segment has been lost. In this case, TCP performs multiplicative decrease and the congestion window is divided by `2`. The slow-start threshold is set to the new value of the congestion window.
0/4080 · 408