2. cnp3-ebook
3. English
4. Zen

149 ../../protocols/wifi.rst:23 • ../../protocols/wifi.rst:25
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — 54 Mbps 7/10000 · 7
149 ../../protocols/tcp.rst:452
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — This retransmission strategy has been refined based on the experience of using TCP on the Internet. The first refinement was a clarification of the strategy used to send acknowledgments. As TCP uses piggybacking, the easiest and less costly method to send acknowledgments is to place them in the data segments sent in the other direction. However, few application layer protocols exchange data in both directions at the same time and thus this method rarely works. For an application that is sending data segments in one direction only, the remote TCP entity returns empty TCP segments whose only useful information is their acknowledgment number. This may cause a large overhead in wide area network if a pure `ACK` segment is sent in response to each received data segment. Most TCP implementations use a `delayed acknowledgment` strategy. This strategy ensures that piggybacking is used whenever possible, otherwise pure `ACK` segments are sent for every second received data segments when there are no losses. When there are losses or reordering, `ACK` segments are more important for the sender and they are sent immediately :rfc:`813` :rfc:`1122`. This strategy relies on a new timer with a short delay (e.g. 50 milliseconds) and one additional flag in the TCB. It can be implemented as follows. 1301/10000 · 1301
149 ../../bibliography.rst:362
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Wessels, D., Fomenkov, M., `Wow, That's a lot of packets <https://www.caida.org/publications/papers/2003/dnspackets/>`_, Passive and Active Network Measurement Workshop (PAM), Apr 2003 185/10000 · 185
149 ../../principles/reliability.rst:508
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Checksums, CRCs,... 19/10000 · 19
150 ../../bibliography.rst:363
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Williams, R. `A painless guide to CRC error detection algorithms`, August 1993, unpublished manuscript, https://web.archive.org/web/20060101004751/http://www.ross.net/crc/download/crc_v3.txt 190/10000 · 190
150 ../../glossary.rst:171
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — router 6/10000 · 6
150 ../../principles/sharing.rst:936
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — no link in the network is congested 35/10000 · 35
150 ../../protocols/email.rst:258
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — v 1/10000 · 1
150 ../../protocols/ipv6.rst:501
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Given the size of the IPv6 header, it can cause huge overhead on low bandwidth links, especially when small packets are exchanged such as for Voice over IP applications. In such environments, several techniques can be used to reduce the overhead. A first solution is to use data compression in the datalink layer to compress all the information exchanged [Thomborson1992]_. These techniques are similar to the data compression algorithms used in tools such as :manpage:`compress(1)` or :manpage:`gzip(1)` :rfc:`1951`. They compress streams of bits without taking advantage of the fact that these streams contain IP packets with a known structure. A second solution is to compress the IP and TCP header. These header compression techniques, such as the one defined in :rfc:`5795` take advantage of the redundancy found in successive packets from the same flow to significantly reduce the size of the protocol headers. Another solution is to define a compressed encoding of the IPv6 header that matches the capabilities of the underlying datalink layer :rfc:`4944`. 1063/10000 · 1063
150 ../../protocols/wifi.rst:23
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — 35/120 6/10000 · 6
150 ../../protocols/tcp.rst:480
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Due to this delayed acknowledgment strategy, during a bulk transfer, a TCP implementation usually acknowledges every second TCP segment received. 145/10000 · 145
150 ../../principles/dv.rst:214
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — At this point, all routers have a routing table allowing them to reach all other routers, except router `A`, which cannot yet reach router `B`. `A` recovers the route towards `B` once router `D` sends its updated distance vector :math:`[A=1,B=2,C=2,D=0,E=1]`. This last step is illustrated in figure below, which shows the routing tables on all routers. 353/10000 · 353
150 ../../principles/reliability.rst:510
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Most of the protocols in the TCP/IP protocol suite rely on the simple Internet checksum in order to verify that a received packet has not been affected by transmission errors. Despite its popularity and ease of implementation, the Internet checksum is not the only available checksum mechanism. Cyclical Redundancy Checks (CRC_) are very powerful error detection schemes that are used notably on disks, by many datalink layer protocols and file formats such as ``zip`` or ``png``. They can easily be implemented efficiently in hardware and have better error-detection capabilities than the Internet checksum [SGP98]_ . However, CRCs are sometimes considered to be too CPU-intensive for software implementations and other checksum mechanisms are preferred. The TCP/IP community chose the Internet checksum, the OSI community chose the Fletcher checksum [Sklower89]_. Nowadays there are efficient techniques to quickly compute CRCs in software [Feldmeier95]_. 957/10000 · 957
150 ../../principles/transport.rst:866
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The first solution to release a transport connection is to define a new control segment (e.g. the `DR` segment for Disconnection Request) and consider the connection to be released once this segment has been sent or received. This is illustrated in the figure below. 266/10000 · 266
151 ../../glossary.rst:173
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — A relay operating in the network layer. 39/10000 · 39
151 ../../principles/dv.rst:295
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Consider now that the link between `D` and `E` fails. The network is now partitioned into two disjoint parts: (`A` , `D`) and (`B`, `E`, `C`). The routes towards `B`, `C` and `E` expire first on router `D`. At this time, router `D` updates its routing table. 259/10000 · 259
151 ../../principles/transport.rst:873
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Abrupt connection release 25/10000 · 25
151 ../../principles/sharing.rst:937
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — the rate allocated to source :math:`j` cannot be increased without decreasing the rate allocated to a source :math:`i` whose allocation is smaller than the rate allocated to source :math:`j` [Leboudec2008]_ . 208/10000 · 208
151 ../../protocols/email.rst:260
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — 14 2/10000 · 2
151 ../../protocols/ipv6.rst:503
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The last type of `IPv6 header extension` is the `Routing` header. The ``type 0`` routing header defined in :rfc:`2460` is an example of an IPv6 option that must be processed by some routers. This option is encoded as shown below. 229/10000 · 229