Exit Zen
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../../protocols/ethernet.rst:370
English
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/ipv6.rst:354
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An IPv6 packet containing an TCP segment
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../../protocols/ethernet.rst:353
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Cost
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../../protocols/tcp.rst:271
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`receiving buffer` : a buffer to store all data received from the remote host that has not yet been delivered to the user. Data may be stored in the `receiving buffer` because either it was not received in sequence or because the user is too slow to process it
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../../glossary.rst:295
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ISP
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../../principles/network.rst:373 • ../../principles/network.rst:422 • ../../principles/network.rst:444
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none
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../../principles/transport.rst:544
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We have already described in the datalink layers mechanisms to deal with data losses and transmission errors. These techniques are also used in the transport layer.
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../../principles/sharing.rst:446
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Furthermore, on the wired networks where CSMA/CD is used, collisions are almost the only cause of transmission errors that affect frames. Transmission errors that only affect a few bits inside a frame seldom occur in these wired networks. For this reason, the designers of CSMA/CD chose to completely remove the acknowledgment frames in the datalink layer. When a host transmits a frame, it verifies whether its transmission has been affected by a collision. If not, given the negligible Bit Error Ratio of the underlying network, it assumes that the frame was received correctly by its destination. Otherwise the frame is retransmitted after some delay.
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../../principles/security.rst:979
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Mallory computes :math:`S_{A}=A^{m} \mod p` and :math:`S_{B}=B^{m} \mod p`
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../../exercises/ipv6.rst:919
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On host ``b``, the problem is different. The packets that it sends towards host ``a`` do not seem to go beyond router ``r3``.
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../../protocols/bgp.rst:377
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Asymmetry of Internet paths
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../../protocols/email.rst:244
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23
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../../protocols/ethernet.rst:373
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Port state
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../../protocols/ipv6.rst:358
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However, the `Next header` has broader usages than simply indicating the transport protocol which is responsible for the packet payload. An IPv6 packet can contain a chain of headers and the last one indicates the transport protocol that is responsible for the packet payload. Supporting a chain of headers is a clever design from an extensibility viewpoint. As we will see, this chain of headers has several usages.
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../../protocols/ethernet.rst:355
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10 Mbps
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../../protocols/tcp.rst:274
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The original TCP specification can be summarized as a transport protocol that provides a byte stream service and uses `go-back-n` with a `selective-repeat` reception strategy.
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../../glossary.rst:297
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An Internet Service Provider, i.e. a network that provides Internet access to its clients.
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../../principles/network.rst:375 • ../../principles/network.rst:377
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2
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../../principles/reliability.rst:339
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These two types of frames can be distinguished by dividing the frame in two parts :
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../../principles/transport.rst:548
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Connectionless transport
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