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39 ../../principles/reliability.rst:189
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — All the functions related to the physical transmission or information through a wire (or a wireless link) are usually known as the `physical layer`. The physical layer allows thus two or more entities that are directly attached to the same transmission medium to exchange bits. Being able to exchange bits is important as virtually any information can be encoded as a sequence of bits. Electrical engineers are used to processing streams of bits, but computer scientists usually prefer to deal with higher level concepts. A similar issue arises with file storage. Storage devices such as hard-disks also store streams of bits. There are hardware devices that process the bit stream produced by a hard-disk, but computer scientists have designed filesystems to allow applications to easily access such storage devices. These filesystems are typically divided into several layers as well. Hard-disks store sectors of 512 bytes or more. Unix filesystems group sectors in larger blocks that can contain data or `inodes` representing the structure of the filesystem. Finally, applications manipulate files and directories that are translated in blocks, sectors and eventually bits by the operating system. 1200/10000 · 1200
39 ../../principles/transport.rst:101
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Besides character strings, some applications also need to exchange 16 bits and 32 bits fields such as integers. A naive solution would have been to send the 16- or 32-bits field as it is encoded in the host's memory. Unfortunately, there are different methods to store 16- or 32-bits fields in memory. Some CPUs store the most significant byte of a 16-bits field in the first address of the field while others store the least significant byte at this location. When networked applications running on different CPUs exchange 16 bits fields, there are two possibilities to transfer them over the transport service : 613/10000 · 613
39 ../../principles/security.rst:396
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The Rivest Shamir Adleman (RSA) algorithm [#frsa]_ proposed in [RSA1978]_ that relies on modular exponentiation with large integers. 132/10000 · 132
39 ../../exercises/ipv6.rst:399
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — on router ``R4`` 16/10000 · 16
39 ../../exercises/routing-protocols.rst:454
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The `addDaemon` method adds a BGP daemon on each router and configures it to advertise the IPv6 prefix allocated to this AS. We then create all the links and manually assign one IPv6 subnet to each link and one IPv6 address to each interface. For the interdomain links, we use an IPv6 prefix that belongs to one of the attached ASes. 333/10000 · 333
39 ../../exercises/tcp-2.rst:459
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Some TCP clients use delayed acknowledgments and send a TCP acknowledgment after after second in-sequence segment. This behavior is illustrated in the script below. This script is available from :download:`/exercises/packetdrill_scripts/slow-start-delayed.pkt`. 261/10000 · 261
39 ../../protocols/bgp.rst:126
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — `UPDATE`: this message is used to advertise new or modified routes or to withdraw previously advertised routes. 111/10000 · 111
39 ../../protocols/congestion.rst:203
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — However, given the regular losses that we consider, the number of segments that are sent between two losses (i.e. during a cycle) is by definition equal to :math:`\frac{1}{p}`. Thus, :math:`W=\sqrt{\frac{8}{3 \times p}}=\frac{k}{\sqrt{p}}`. The throughput (in bytes per second) of the TCP connection is equal to the number of segments transmitted divided by the duration of the cycle : 385/10000 · 385
39 ../../protocols/email.rst:210
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The `Content-Type:` header can also be used inside a MIME part. In this case, it indicates the type of data placed in this part. Each data type is specified as a type followed by a subtype. A detailed description may be found in :rfc:`2046`. Some of the most popular `Content-Type:` header lines are : 301/10000 · 301
39 ../../protocols/ethernet.rst:176
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Two multi-mode optical fiber, 2 km maximum 42/10000 · 42
39 ../../protocols/http.rst:159
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — the `Content-Type:` header is the :term:`MIME` header that indicates the type of the attached MIME document. HTML pages use the `text/html` type. 145/10000 · 145
39 ../../protocols/http2.rst:266
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Footnotes 9/10000 · 9
39 ../../protocols/ipv6.rst:130
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — IPv6 supports unicast, multicast and anycast addresses. An IPv6 unicast address is used to identify one datalink-layer interface on a host. If a host has several datalink layer interfaces (e.g. an Ethernet interface and a WiFi interface), then it needs several IPv6 addresses. In general, an IPv6 unicast address is structured as shown in the figure below. 356/10000 · 356
39 ../../protocols/ethernet.rst:162
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — In the late 1980s, 10 Mbps became too slow for some applications and network manufacturers developed several LAN technologies that offered higher bandwidth, such as the 100 Mbps FDDI LAN that used optical fibers. As the development of 10Base5, 10Base2 and 10BaseT had shown that Ethernet could be adapted to different physical layers, several manufacturers started to work on 100 Mbps Ethernet and convinced IEEE to standardize this new technology that was initially called `Fast Ethernet`. `Fast Ethernet` was designed under two constraints. First, `Fast Ethernet` had to support twisted pairs. Although it was easier from a physical layer perspective to support higher bandwidth on coaxial cables than on twisted pairs, coaxial cables were a nightmare from deployment and maintenance perspectives. Second, `Fast Ethernet` had to be perfectly compatible with the existing 10 Mbps Ethernet to allow `Fast Ethernet` technology to be used initially as a backbone technology to interconnect 10 Mbps Ethernet networks. This forced `Fast Ethernet` to use exactly the same frame format as 10 Mbps Ethernet. This implied that the minimum `Fast Ethernet` frame size remained at 512 bits. To preserve CSMA/CD with this minimum frame size and 100 Mbps instead of 10 Mbps, the duration of the `slot time` was decreased to 5.12 microseconds. 1329/10000 · 1329
39 ../../protocols/routing.rst:132
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Each router must exchange HELLOs and link state packets with all the other routers on the LAN. This increases the number of OSPF packets that are sent and processed by each router. 180/10000 · 180
39 ../../protocols/rpc.rst:138
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The `id` field, which is present in the request and the response plays the same role as the identifier field in the DNS message. It allows the caller to match the response with the request that it sent. This `id` is very important when JSON-RPC is used over the connectionless transport service which is unreliable. If a request is sent, it may need to be retransmitted and it is possible that a callee will receive twice the same request (e.g. if the response for the first request was lost). In the DNS, when a request is lost, it can be retransmitted without causing any difficulty. However with remote procedure calls in general, losses can cause some problems. Consider a method which is used to deposit money on a bank account. If the request is lost, it will be retransmitted and the deposit will be eventually performed. However, if the response is lost, the caller will also retransmit its request. This request will be received by the callee that will deposit the money again. To prevent this problem from affecting the application, either the programmer must ensure that the remote procedures that it calls can be safely called multiple times or the application must verify whether the request has been transmitted earlier. In most deployments, the programmers use remote methods that can be safely called multiple times without breaking the application logic. 1371/10000 · 1371
39 ../../protocols/ssh.rst:296
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — For some of the algorithms, it is possible to negotiate the utilization of no algorithm. This happens frequently for the compression algorithm that is not always used. For this, both the client and the server must announce ``null`` in their ordered list of supported algorithms. 278/10000 · 278
39 ../../protocols/tcp.rst:121
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — the `acknowledgment number` set to the `sequence number` of the received `SYN` segment incremented by 1 :math:`\pmod{2^{32}}`. When a TCP entity sends a segment having `x+1` as acknowledgment number, this indicates that it has received all data up to and including sequence number `x` and that it is expecting data having sequence number `x+1`. As the `SYN` flag was set in a segment having sequence number `x`, this implies that setting the `SYN` flag in a segment consumes one sequence number. 495/10000 · 495
39 ../../protocols/tls.rst:167
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — `Extensions` : TLS supports various extensions in the ``ClientHello`` message. These extensions :rfc:`6066` are important to allow the protocol to evolve, but many of them go beyond the scope of this chapter. 208/10000 · 208
39 ../../protocols/wifi.rst:99
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — 802.11 data frame format 24/10000 · 24