2. cnp3-ebook
3. English
4. Zen

20 ../../protocols/routing.rst:67
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Link-state routing protocols are used in IP networks. Open Shortest Path First (OSPF), defined in :rfc:`2328`, is the link state routing protocol that has been standardized by the IETF. The last version of OSPF, which supports IPv6, is defined in :rfc:`5340`. OSPF is frequently used in enterprise networks and in some ISP networks. However, ISP networks often use the IS-IS link-state routing protocol [ISO10589]_ , which was developed for the ISO CLNP protocol but was adapted to be used in IP :rfc:`1195` networks before the finalization of the standardization of OSPF. A detailed analysis of ISIS and OSPF may be found in [BMO2006]_ and [Perlman2000]_. Additional information about OSPF may be found in [Moy1998]_. 719/10000 · 719
20 ../../protocols/rpc.rst:86
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — This object has one field named `Image`. It has five attributes. The first one, `Width`, is an integer set to 800. The third one is a string. The fourth attribute, `Thumbnail` is also an object composed of three different attributes, one string and two integers. JSON can also be used to encode arrays or lists. In this case, square brackets are used as delimiters. The snippet below shows an array which contains the prime integers that are smaller than ten. 459/10000 · 459
20 ../../protocols/ssh.rst:173
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The second point is that the server authenticates not only the result of the Diffie Hellman exchange but also a hash of all the information sent and received during the exchange. This is important to prevent `downgrade attacks`. A `downgrade attack` is an attack where an active attacker modifies the messages sent by the communicating hosts (typically the client) to request the utilization of weaker encryption algorithms. Consider a client that supports two encryption schemes. The preferred one uses 128 bits secret keys and the second one is an old encryption scheme that uses 48 bits keys. This second algorithm is kept for backward compatibility with older implementations. If an attacker can remove the preferred algorithm from the list of encryption algorithms supported by the client, he can force the server to use a weaker encryption scheme that will be easier to break. Thanks to the hash that covers all the messages exchanged by the server, the downgrade attack cannot occur against ``ssh``. Algorithm agility is a key requirement for security protocols that need to evolve when encryption algorithms are broken by researchers. This agility cannot be used without care and signing a hash of all the messages exchanged is a technique that is frequently used to prevent downgrade attacks. 1301/10000 · 1301
20 ../../protocols/tcp.rst:46
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — the flags field contains a set of bit flags that indicate how a segment should be interpreted by the TCP entity receiving it : 126/10000 · 126
20 ../../protocols/tls.rst:46
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — 443 3/10000 · 3
20 ../../protocols/transport-service.rst:59
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — `ff01:0:0:0:0:0:0:101` is represented as `ff01::101` 54/10000 · 54
20 ../../protocols/udp.rst:69
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Computation of the UDP checksum 31/10000 · 31
20 ../../protocols/wifi.rst:23
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — 35/120 6/10000 · 6
20 ../../exercises/sockets.rst:175
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — While the provided examples show the usage of a `char` array as the data buffer, implementers should **never** assume that it contains a string. C programs rely on the `char` type to refer to a 8-bit long value, and arbitrary binary values can be exchanged over the network (i.e., the ``\0`` value does not delimit the end of the data). 336/10000 · 336
20 ../../principles/sharing.rst:186
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — If `R1` has enough buffers, it will be able to absorb the load without having to discard packets. The packets sent by hosts `A` and `B` will reach their final destination `C`, but will experience a longer delay than when they are transmitting alone. The amount of buffering on the network node is the first parameter that a network operator can tune to control congestion inside his network. Given the decreasing cost of memory, one could be tempted to put as many buffers [#fbufferbloat]_ as possible on the network nodes. Let us consider this case in the network above and assume that `R1` has infinite buffers. Assume now that hosts `A` and `B` try to transmit a file that corresponds to one thousand packets each. Both are using a reliable protocol that relies on go-back-n to recover from transmission errors. The transmission starts and packets start to accumulate in `R1`'s buffers. The presence of these packets in the buffers increases the delay between the transmission of a packet by `A` and the return of the corresponding acknowledgment. Given the increasing delay, host `A` (and `B` as well) will consider that some of the packets that it sent have been lost. These packets will be retransmitted and will enter the buffers of `R1`. The occupancy of the buffers of `R1` will continue to increase and the delays as well. This will cause new retransmissions, ... In the end, only one file will be delivered (very slowly) to the destination, but the link `R1-R2` will transfer much more bytes than the size of the file due to the multiple copies of the same packets. This is known as the `congestion collapse` problem :rfc:`896`. Congestion collapse is the nightmare for network operators. When it happens, the network carries packets without delivering useful data to the end users. 1793/10000 · 1793
21 ../../exercises/ex-sharing.rst:491
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — In general, the links have a non-zero delay. This is illustrated in the figure below where a delay has been added on the link between `R` and `C`. 146/10000 · 146
21 ../../exercises/sockets.rst:177
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Using this code, the program will read and print an arbitrary message received from an arbitrary peer who knows the program's socket address. If we want to know the address of the peer that sent us the message, we can use the ``recvfrom`` system call. This is what a modified version of ``bind_and_receive_from_peer`` is doing below. 333/10000 · 333
21 ../../principles/naming.rst:116
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Each root nameserver maintains the list [#froot]_ of all the nameservers that are responsible for each of the top-level domain names and their addresses [#frootv6]_. All root nameservers cooperate and provide the same answers. By querying any of the root nameservers, a DNS client can obtain the nameserver that is responsible for any top-level-domain name. From this nameserver, it is possible to resolve any domain name. 422/10000 · 422
21 ../../principles/network.rst:103
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — the information to be sent 26/10000 · 26
21 ../../principles/referencemodels.rst:168
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The upper layer of our architecture is the `Application layer`. This layer includes all the mechanisms and data structures that are necessary for the applications. We will use Application Data Unit (ADU) or the generic Service Data Unit (SDU) term to indicate the data exchanged between two entities of the Application layer. 325/10000 · 325
21 ../../principles/reliability.rst:59
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — To understand some of the principles behind the physical transmission of information, let us consider the simple case of an electrical wire that is used to transmit bits. Assume that the two communicating hosts want to transmit one thousand bits per second. To transmit these bits, the two hosts can agree on the following rules : 330/10000 · 330
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