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152 ../../protocols/tcp.rst:486
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The first extension that was proposed is the fast retransmit heuristic. This extension can be implemented on TCP senders and thus does not require any change to the protocol. It only assumes that the TCP receiver is able to buffer out-of-sequence segments. 256/10000 · 256
152 ../../principles/reliability.rst:555
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Unfortunately, retransmission timers alone are not sufficient to recover from losses. Let us consider, as an example, the situation depicted below where an acknowledgment is lost. In this case, the sender retransmits the data frame that has not been acknowledged. However, as illustrated in the figure below, the receiver considers the retransmission as a new frame whose payload must be delivered to its user. 410/10000 · 410
153 ../../glossary.rst:204
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Several types of remote procedure calls have been defined. The RPC mechanism defined in :rfc:`5531` is used by applications such as NFS 135/10000 · 135
153 ../../principles/dv.rst:299
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Unfortunately, if the distance vector sent to `A` is lost or if `A` sends its own distance vector ( :math:`[A=0,D=1,B=3,C=3,E=2]` ) at the same time as `D` sends its distance vector, `D` updates its routing table to use the shorter routes advertised by `A` towards `B`, `C` and `E`. After some time `D` sends a new distance vector : :math:`[D=0,A=1,E=3,C=4,B=4]`. `A` updates its routing table and after some time sends its own distance vector :math:`[A=0,D=1,B=5,C=5,E=4]`, etc. This problem is known as the `count to infinity problem` in the networking literature. 566/10000 · 566
153 ../../principles/reliability.rst:586
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — To solve this problem, datalink protocols associate a `sequence number` to each data frame. This `sequence number` is one of the fields found in the header of data frames. We use the notation `D(x,...)` to indicate a data frame whose sequence number field is set to value `x`. The acknowledgments also contain a sequence number indicating the data frames that it is acknowledging. We use `OKx` to indicate an acknowledgment frame that confirms the reception of `D(x,...)`. The sequence number is encoded as a bit string of fixed length. The simplest reliable protocol is the Alternating Bit Protocol (ABP). 606/10000 · 606
153 ../../principles/transport.rst:879
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The second method to release a transport connection is to release independently the two directions of data transfer. Once a user of the transport service has sent all its SDUs, it performs a `DISCONNECT.req` for its direction of data transfer. The transport entity sends a control segment to request the release of the connection *after* the delivery of all previous SDUs to the remote user. This is usually done by placing in the `DR` the next sequence number and by delivering the `DISCONNECT.ind` only after all previous `DATA.ind`. The remote entity confirms the reception of the `DR` segment and the release of the corresponding direction of data transfer by returning an acknowledgment. This is illustrated in the figure below. 733/10000 · 733
153 ../../principles/sharing.rst:941
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — To visualize the different rate allocations, it is useful to consider the graph shown below. In this graph, we plot on the `x-axis` (resp. `y-axis`) the rate allocated to host `B` (resp. `A`). A point in the graph :math:`(r_B,r_A)` corresponds to a possible allocation of the transmission rates. Since there is a `2 Mbps` bottleneck link in this network, the graph can be divided into two regions. The lower left part of the graph contains all allocations :math:`(r_B,r_A)` such that the bottleneck link is not congested (:math:`r_A+r_B<2`). The right border of this region is the `efficiency line`, i.e. the set of allocations that completely utilize the bottleneck link (:math:`r_A+r_B=2`). Finally, the `fairness line` is the set of fair allocations. 753/10000 · 753
153 ../../protocols/email.rst:260
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — 31 2/10000 · 2
153 ../../protocols/ipv6.rst:512
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — The type 0 routing option was intended to allow a host to indicate a loose source route that should be followed by a packet by specifying the addresses of some of the routers that must forward this packet. Unfortunately, further work with this routing header, including an entertaining demonstration with scapy_ [BE2007]_ , revealed severe security problems with this routing header. For this reason, loose source routing with the type 0 routing header has been removed from the IPv6 specification :rfc:`5095`. 510/10000 · 510
153 ../../protocols/wifi.rst:24
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — 11 Mbps 7/10000 · 7
153 ../../protocols/tcp.rst:488
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — From a performance point of view, one issue with TCP's `retransmission timeout` is that when there are isolated segment losses, the TCP sender often remains idle waiting for the expiration of its retransmission timeouts. Such isolated losses are frequent in the global Internet [Paxson99]_. A heuristic to deal with isolated losses without waiting for the expiration of the retransmission timeout has been included in many TCP implementations since the early 1990s. To understand this heuristic, let us consider the figure below that shows the segments exchanged over a TCP connection when an isolated segment is lost. 619/10000 · 619
153 ../../bibliography.rst:370
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Ylonen, T., `SSH — Secure Login Connections over the Internet <https://www.usenix.org/legacy/publications/library/proceedings/sec96/full_papers/ylonen/index.html>`_, Usenix Security 1996 186/10000 · 186
154 ../../glossary.rst:63
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — SDU (Service Data Unit) 23/10000 · 23
154 ../../principles/dv.rst:301
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Routers `A` and `D` exchange distance vectors with increasing costs until these costs reach :math:`\infty`. This problem may occur in other scenarios than the one depicted in the above figure. In fact, distance vector routing may suffer from count to infinity problems as soon as there is a cycle in the network. Unfortunately, cycles are widely used in networks since they provide the required redundancy to deal with link and router failures. To mitigate the impact of counting to infinity, some distance vector protocols consider that :math:`16=\infty`. Unfortunately, this limits the metrics that network operators can use and the diameter of the networks using distance vectors. 683/10000 · 683
154 ../../principles/transport.rst:885
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Graceful connection release 27/10000 · 27
154 ../../principles/sharing.rst:947
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Possible allocated transmission rates 37/10000 · 37
154 ../../protocols/email.rst:260
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — f 1/10000 · 1
154 ../../protocols/ipv6.rst:520
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — ICMP version 6 14/10000 · 14
154 ../../protocols/wifi.rst:24 • ../../protocols/wifi.rst:25
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — 38/140 6/10000 · 6
154 ../../protocols/tcp.rst:494
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Detecting isolated segment losses 33/10000 · 33