Exit Zen
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../../protocols/email.rst:248 • ../../protocols/email.rst:250
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8
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../../protocols/ethernet.rst:393
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Assume now that `Switch9` boots and immediately receives `Switch1` 's `BPDU` on port 1. `Switch9` computes its own `BPDU = <1,1,9,1>` (resp. `BPDU = <1,1,9,2>`) on port 1 (resp. port 2) and port 1 becomes the `Root` port of this switch. The `BPDU` is sent on port 2 of `Switch9` and reaches `Switch4`. `Switch4` compares the priority vectors. It notices that the last computed vector (i.e., `V[2] = <1,2,9,2,2>`) is better than `V[1] = <1,3,1,1,1>`. Thus, `Switch4`'s `BPDU` is recomputed and port 2 becomes the `Root` port of `Switch4`. `Switch4` compares its new `BPDU = <1,2,4,p>` with the last `BPDU` received on each port (except for the `Root` port). Port 1 becomes a `Blocked` port on `Switch4` because the `BPDU=<1,0,1,1>` received on this port is better.
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../../protocols/ipv6.rst:380
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``00`` : if a node does not recognize this header, it can be safely skipped and the processing continues with the subsequent header
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../../protocols/ethernet.rst:368
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To determine the state of its other ports, the switch compares its own `BPDU` with the last `BPDU` received on each port. Note that the comparison is done by using the `BPDUs` and not the `root priority vectors`. If the switch's `BPDU` is better than the last `BPDU` of this port, the port becomes a `Designated` port. Otherwise, the port becomes a `Blocked` port.
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../../protocols/tcp.rst:329
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From a performance point of view, one of the main limitations of the original TCP specification is the 16 bits `window` field in the TCP header. As this field indicates the current size of the receive window in bytes, it limits the TCP receive window at 65535 bytes. This limitation was not a severe problem when TCP was designed since at that time high-speed wide area networks offered a maximum bandwidth of 56 kbps. However, in today's network, this limitation is not acceptable anymore. The table below provides the rough [#faveragebandwidth]_ maximum throughput that can be achieved by a TCP connection with a 64 KBytes window in function of the connection's round-trip-time
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../../glossary.rst:255
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The Multipurpose Internet Mail Extensions (MIME) defined in :rfc:`2045` are a set of extensions to the format of email messages that allow to use non-ASCII characters inside mail messages. A MIME message can be composed of several different parts each having a different format.
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../../principles/transport.rst:579
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An important difference between the connectionless service and the connection-oriented one is that the transport entities in the latter maintain some state during lifetime of the connection. This state is created when a connection is established and is removed when it is released.
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../../principles/sharing.rst:507
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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.
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../../principles/security.rst:1024
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A detailed explanation of the ECC cryptosystems is outside the scope of this e-book. A simple introduction may be found on `Andrea Corbellini's blog <http://andrea.corbellini.name/2015/05/17/elliptic-curve-cryptography-a-gentle-introduction/>`_. There have been deployments of ECC recently because ECC schemes usually require shorter keys than RSA and consume less CPU.
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../../protocols/bgp.rst:415
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`AS1` prefers the path `AS3:AS0` over all other paths
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../../protocols/email.rst:248
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I
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../../protocols/ethernet.rst:395
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During the computation of the spanning tree, switches discard all received data frames, as at that time the network topology is not guaranteed to be loop-free. Once that topology has been stable for some time, the switches again start to use the MAC learning algorithm to forward data frames. Only the `Root` and `Designated` ports are used to forward data frames. Switches discard all the data frames received on their `Blocked` ports and never forward frames on these ports.
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../../protocols/ipv6.rst:381
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``01`` : if a node does not recognize this header, the packet must be discarded
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../../protocols/ethernet.rst:370
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The state of each port is important when considering the transmission of `BPDUs`. The root switch regularly sends its own `BPDU` over all of its (`Designated`) ports. This `BPDU` is received on the `Root` port of all the switches that are directly connected to the `root switch`. Each of these switches computes its own `BPDU` and sends this `BPDU` over all its `Designated` ports. These `BPDUs` are then received on the `Root` port of downstream switches, which then compute their own `BPDU`, etc. When the network topology is stable, switches send their own `BPDU` on all their `Designated` ports, once they receive a `BPDU` on their `Root` port. No `BPDU` is sent on a `Blocked` port. Switches listen for `BPDUs` on their `Blocked` and `Designated` ports, but no `BPDU` should be received over these ports when the topology is stable. The utilization of the ports for both `BPDUs` and data frames is summarized in the table below.
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../../protocols/tcp.rst:332 • ../../protocols/tcp.rst:345
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RTT
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../../glossary.rst:277
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MIME document
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../../principles/network.rst:442
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->R3
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../../principles/reliability.rst:399
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To deal with these types of imperfections, reliable protocols rely on different types of mechanisms. The first problem is transmission errors. Data transmission on a physical link can be affected by the following errors :
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../../principles/sharing.rst:513
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Carrier Sense Multiple Access with Collision Avoidance
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../../protocols/bgp.rst:416
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`AS3` prefers the path `AS4:AS0` over all other paths
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