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184 ../../principles/reliability.rst:951
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — `Selective repeat` is a better strategy to recover from losses. Intuitively, `selective repeat` allows the receiver to accept out-of-sequence frames. Furthermore, when a `selective repeat` sender detects losses, it only retransmits the frames that have been lost and not the frames that have already been correctly received. 324/10000 · 324
184 ../../principles/linkstate.rst:88
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — This comparison takes into account the modulo :math:`2^{6}` arithmetic used to increment the sequence numbers. Intuitively, the comparison divides the circle of all sequence numbers into two halves. Usually, the sequence number of the received LSP is equal to the sequence number of the stored LSP incremented by one, but sometimes the sequence numbers of two successive LSPs may differ, e.g. if one router has been disconnected for some time. The comparison above worked well until October 27, 1980. On this day, the ARPANET crashed completely. The crash was complex and involved several routers. At one point, LSP `40` and LSP `44` from one of the routers were stored in the LSDB of some routers in the ARPANET. As LSP `44` was the newest, it should have replaced LSP `40` on all routers. Unfortunately, one of the ARPANET routers suffered from a memory problem and sequence number `40` (`101000` in binary) was replaced by `8` (`001000` in binary) in the buggy router and flooded. Three LSPs were present in the network and `44` was newer than `40` which is newer than `8`, but unfortunately `8` was considered to be newer than `44`... All routers started to exchange these three link state packets forever and the only solution to recover from this problem was to shutdown the entire network :rfc:`789`. 1307/10000 · 1307
184 ../../principles/sharing.rst:1522
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Some networking technologies allow to adjust dynamically the bandwidth of links. For example, some devices can reduce their bandwidth to preserve energy. We ignore these technologies in this basic course and assume that all links used inside the network have a fixed bandwidth. 277/10000 · 277
184 ../../protocols/email.rst:297
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — F A \= \= 17/10000 · 17
184 ../../protocols/ipv6.rst:641
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — some multiplexing information to indicate the network layer protocol that is responsible for the payload of the frame 117/10000 · 117
184 ../../protocols/wifi.rst:154
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The second important utilization of the management frames is to allow a WiFi station to be associated with an access point. When a WiFi station starts, it listens to beacon frames to find the available SSIDs. To be allowed to send and receive frames via an access point, a WiFi station must be associated to this access point. If the access point does not use any security mechanism to secure the wireless transmission, the WiFi station simply sends an `Association request` frame to its preferred access point (usually the access point that it receives with the strongest radio signal). This frame contains some parameters chosen by the WiFi station and the SSID that it requests to join. The access point replies with an `Association response frame` if it accepts the WiFI station. 783/10000 · 783
184 ../../protocols/tcp.rst:621
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — A detailed presentation of all standardization documents concerning TCP may be found in :rfc:`4614` 99/10000 · 99
185 ../../glossary.rst:295
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Transport Layer Security, defined in :rfc:`5246` is a cryptographic protocol that is used to provide communication security for Internet applications. This protocol is used on top of the transport service but a detailed description is outside the scope of this book. 266/10000 · 266
185 ../../principles/sharing.rst:1524
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — This name should not be confused with the duration of a transmission slot in slotted ALOHA. In CSMA/CD networks, the slot time is the time during which a collision can occur at the beginning of the transmission of a frame. In slotted ALOHA, the duration of a slot is the transmission time of an entire fixed-size frame. 319/10000 · 319
185 ../../principles/reliability.rst:953
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — A `selective repeat` receiver maintains a sliding window of `W` frames and stores in a buffer the out-of-sequence frames that it receives. The figure below shows a five-frame receive window on a receiver that has already received frames `7` and `9`. 249/10000 · 249
185 ../../principles/linkstate.rst:90
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Current link state routing protocols usually use 32 bits sequence numbers and include a special mechanism in the unlikely case that a sequence number reaches the maximum value (with a 32 bits sequence number space, it takes 136 years to cycle the sequence numbers if a link state packet is generated every second). 314/10000 · 314
185 ../../protocols/email.rst:303
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — 0x14b9 6/10000 · 6
185 ../../protocols/ipv6.rst:643
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — LANs also provide a broadcast and a multicast service. The broadcast service enables a device to send a single frame to all the devices attached to the same LAN. This is done by reserving a special broadcast MAC address (typically all bits of the address are set to one). To broadcast a frame, a device simply needs to send a frame whose destination is the broadcast address. All devices attached to the datalink network will receive the frame. 445/10000 · 445
185 ../../protocols/wifi.rst:158
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The 802.11 working group defined the `basic service set (BSS)` as a group of devices that communicate with each other. We continue to use `network` when referring to a set of devices that communicate. 200/10000 · 200
185 ../../protocols/tcp.rst:623
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Several researchers have analyzed the utilization of TCP and UDP in the global Internet. Most of these studies have been performed by collecting all the packets transmitted over a given link during a period of a few hours or days and then analyzing their headers to infer the transport protocol used, the type of application, ... Recent studies include http://www.caida.org/research/traffic-analysis/tcpudpratio/, https://research.sprintlabs.com/packstat/packetoverview.php or http://www.nanog.org/meetings/nanog43/presentations/Labovitz_internetstats_N43.pdf 559/10000 · 559
186 ../../glossary.rst:87
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — UDP 3/10000 · 3
186 ../../principles/reliability.rst:959
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The receiving window with selective repeat 42/10000 · 42
186 ../../principles/linkstate.rst:92
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — To deal with the memory corruption problem, link state packets contain a checksum or CRC. This checksum is computed by the router that generates the LSP. Each router must verify the checksum when it receives or floods an LSP. Furthermore, each router must periodically verify the checksums of the LSPs stored in its LSDB. This enables them to cope with memory errors that could corrupt the LSDB as the one that occurred in the ARPANET. 435/10000 · 435
186 ../../principles/sharing.rst:1526
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — In this section, we focus on congestion control mechanisms that regulate the transmission rate of the hosts. Other types of mechanisms have been proposed in the literature. For example, `credit-based` flow-control has been proposed to avoid congestion in ATM networks [KR1995]_. With a credit-based mechanism, hosts can only send packets once they have received credits from the routers and the credits depend on the occupancy of the router's buffers. 451/10000 · 451
186 ../../protocols/email.rst:305
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — 00010100 11111011 18/10000 · 18